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Time to treatment of esophageal cancer in Ontario: A population-level cross-sectional study

Open AccessPublished:August 19, 2022DOI:https://doi.org/10.1016/j.xjon.2022.08.004

      Abstract

      Objective

      Timely cancer treatment improves survival and anxiety for some sites. Patients with esophageal cancer require specific workup before treatment, which can prolong the time from diagnosis to treatment (treatment interval [TI]). The geographical variation of this interval remains uninvestigated in patients with esophageal cancer.

      Methods

      This retrospective population-level study conducted in Ontario used linked administrative health care databases. Patients treated for esophageal cancer between 2013 and 2018 were included. The TI was time from diagnosis to treatment. Patients were assigned a geographical Local Health Integration Network on the basis of postal code. Covariates included patient, disease, and diagnosing physician characteristics. Quantile regression modeled TI length at the 50th and 90th percentile and identified associated factors.

      Results

      Of 7509 patients, 78% were male and most were aged between 60 and 69 years. The 50th and 90th percentile TI was 36 (interquartile range, 22-55) and 77 days, respectively. The difference between the Local Health Integration Network with the longest and shortest TI at the 50th and 90th percentile was 18 and 25 days, respectively. Older age (P < .0001), greater comorbidity (P = .0005), greater material deprivation (P = .001), rurality (P = .03), histology (P = .02), and treatment group (P < .0001) were associated with a longer median TI. Older age (P = .03), greater comorbidity (P = .003), greater material deprivation (P = .005), rurality (P = .04), and treatment group (P < .0001) were associated with a longer 90th percentile TI.

      Conclusions

      Geographic variability of time to treatment exists across Ontario. Investigation of facility-level differences is warranted. Patient and disease factors are associated with longer wait times. These results might inform future health care policy and resource allocation.

      Graphical abstract

      Key Words

      Abbreviations and Acronyms:

      AC (adenocarcinoma), ADG (Aggregated Diagnosis Group), CIHI (Canadian Institute for Health Information), ED (Emergency Department), ICES (Institute for Clinical Evaluative Sciences), IQR (interquartile range), LHIN (Local Health Integration Network), NACRS (National Ambulatory Care Reporting System), OCR (Ontario Cancer Registry), PCCF (Postal Code Conversion File), SCC (squamous cell carcinoma), TI (treatment interval)
      Figure thumbnail fx2
      Geographical variability exists in the length of the esophageal cancer treatment interval.
      Despite adjusting for numerous confounding variables, geographic variability exists in the time to treatment of esophageal cancer.
      Esophageal cancer management is a complex, multistep process. In Ontario, health regions coordinate the care of their own patients. We found differences in time to first health care encounter and time to treatment between health regions, despite adjusting for numerous covariates. Older, comorbid, and rurally located patients waited longer than others.
      Timely access to cancer treatment has improved survival outcomes for many disease sites,
      • Neal R.D.
      • Tharmanathan P.
      • France B.
      • Din N.U.
      • Cotton S.
      • Fallon-Ferguson J.
      • et al.
      Is increased time to diagnosis and treatment in symptomatic cancer associated with poorer outcomes? Systematic review.
      ,
      • Hanna T.P.
      • King W.D.
      • Thibodeau S.
      • Jalink M.
      • Paulin G.A.
      • Harvey-Jones E.
      • et al.
      Mortality due to cancer treatment delay: systematic review and meta-analysis.
      and reduced anxiety
      • Visser M.R.
      • van Lanschot J.J.
      • van der Velden J.
      • Kloek J.J.
      • Gouma D.J.
      • Sprangers M.A.
      Quality of life in newly diagnosed cancer patients waiting for surgery is seriously impaired.
      and symptom progression while patients await treatment. Patients require time to accommodate staging investigations and specialist visits before treatment begins. Expediting these is crucial in patients with esophageal cancer because of the number of patients who present with locally advanced disease.
      Between 2005 and 2010, Ontario Health Cancer Care Ontario regionalized thoracic cancer management. Only hospitals that maintained adequate surgical volumes for lung and esophageal resection, including the appropriate personnel and equipment, received funding to manage these patients.
      • Sundaresan S.
      • Langer B.
      • Oliver T.
      • Schwartz F.
      • Brouwers M.
      • Stern H.
      Standards for thoracic surgical oncology in a single-payer healthcare system.
      They postulated that having 1 institution centralize the workup and treatment of esophageal cancer in that region might reduce the number of missed appointments, repeat investigations, and therefore reduce the overall time between diagnosis and treatment (treatment interval [TI]).
      • Darling G.E.
      Regionalization in thoracic surgery: the importance of the team.
      Since regionalization, little has been reported on wait times for esophageal cancer treatment in Ontario.
      Few studies have examined subintervals within the TI. One research group
      • Li X.
      • Scarfe A.
      • King K.
      • Fenton D.
      • Butts C.
      • Winget M.
      Timeliness of cancer care from diagnosis to treatment: a comparison between patients with breast, colon, rectal or lung cancer.
      ,
      • Winget M.
      • Turner D.
      • Tonita J.
      • King C.
      • Nugent Z.
      • Alvi R.
      • et al.
      Across-province standardization and comparative analysis of time-to-care intervals for cancer.
      partitioned the TI of patients with breast, lung, colon, or rectal cancer into time from diagnosis to the first oncologist consult, and time from the first oncologist consult to treatment. These subintervals have not yet been investigated for esophageal cancer in Canada.
      A detailed understanding of the esophageal cancer TI might help improve equitable access to necessary investigations and treatments. Knowledge of the subinterval that contributes most to the TI might inform refinements to the patient pathway and resource allocation. In this study, we aimed to describe the lengths of the TI and subintervals, to investigate the geographical variation of the TI across Ontario, and to evaluate factors associated with the length of those intervals in Ontario esophageal cancer patients.

      Methods

      Study Design

      We conducted a population-level cross-sectional study using linked administrative health care databases housed at Institute for Clinical Evaluative Sciences (ICES). ICES is an independent, nonprofit research institute funded by an annual grant from the Ontario Ministry of Health and the Ministry of Long-Term Care. As a prescribed entity under Ontario's privacy legislation, ICES is authorized to collect and use health care data for the purposes of health system analysis, evaluation, and decision support. Secure access to these data is governed by policies and procedures that are approved by the Information and Privacy Commissioner of Ontario. In Canada, health care is delivered under a universal government-funded system. A population of 14.7 million residents makes Ontario the most inhabited Canadian province. This study was approved by the Research Ethics Board of Queen's University (approval number 6030561; approval date: October 5, 2020).

      Data Sources

      Patients were identified in the Ontario Cancer Registry (OCR), a province-wide database that captures >96% of all incident cancers.
      • Robles S.C.
      • Marrett L.D.
      • Clarke E.A.
      • Risch H.A.
      An application of capture-recapture methods to the estimation of completeness of cancer registration.
      The OCR was linked to other health administrative databases to obtain demographic, disease, billing, and outcomes data. We used the Registered Persons Database, National Ambulatory Care Reporting System (NACRS), Discharge Abstract Database, Ontario Health Insurance Plan (OHIP), Same Day Surgery, Postal Code Conversion File (PCCF), Local Health Integration Network (LHIN),
      • Ministry of Health and Long Term Care
      Facts about LHINs.
      Ontario Marginalisation Database, Immigration, Refugees, and Citizenship Canada Permanent Resident Database, Activity Level Reporting, and ICES Physician Database (Table E1). These databases were linked using unique encoded identifiers at ICES.

      Study Population

      Adult patients diagnosed with incident esophageal cancer between 2013 and 2018 who received treatment were included. Cancer site was identified using topography codes; histology was not restricted (Table E2). Patients were excluded if there was no biopsy procedure, if there was no investigation or consultation between diagnosis and treatment, or if treatment was <4 days or 6 months after diagnosis (Figure 1). Less than 4 days was chosen to exclude patients who presented emergently and had expedited treatment and so were unlikely to have followed the Cancer Care Ontario treatment pathway, and has been previously reported.
      • Hanna N.M.
      • Williams E.
      • Kong W.
      • Fundytus A.
      • Booth C.M.
      • Patel S.V.
      • et al.
      Incidence, timing, and outcomes of venous thromboembolism in patients undergoing surgery for esophagogastric cancer: a population-based cohort study.
      Figure thumbnail gr1
      Figure 1Cohort creation. OHIP, Ontario Health Insurance Plan; ICES, Institute for Clinical Evaluative Sciences.

      TIs

      TI length was defined as the number of days from diagnosis to the first treatment. Secondary outcomes were the length of subinterval 1 (time from diagnosis to the first cancer-related event thereafter) and subinterval 2 (time from the first cancer-related event to treatment). The first cancer-related event could be either a specialist visit or an investigation (Table E3).

      Date of Diagnosis

      We first identified the diagnosis date in the OCR, and then used NACRS, Canadian Institute for Health Information (CIHI), and Ontario Health Insurance Plan billing date to identify the date of an endoscopic biopsy within 2 weeks of the OCR date. For those with a biopsy record on the same day as the OCR, this date was assigned the diagnosis date. For the remainder, the earliest biopsy date was used. For those for whom the biopsy date was >2 weeks before or after the corresponding OCR date, we used that OCR date as the diagnosis date.

      Covariates

      Age and sex were categorized. Comorbidity information was gathered from 6 to 30 months before the diagnosis date and categorized on the basis of the Johns Hopkins Aggregated Diagnosis Groups (ADGs). The ADGs were created using the Johns Hopkins ACG System v10.0.1 (build 879). Rurality was dichotomized into urban/rural using the PCCF. LHINs are geographical health regions within Ontario tasked to fund and distribute health care to residents living within their borders.
      • Ministry of Health and Long Term Care
      Facts about LHINs.
      During the study period, there were 14 LHINs. Each patient was assigned a LHIN depending on their postal code at diagnosis using the PCCF and LHIN databases. Material deprivation is an objective marker of socioeconomic status
      • Matheson F.I.
      • Dunn J.R.
      • Smith K.L.
      • Moineddin R.
      • Glazier R.H.
      Development of the Canadian Marginalization Index: a new tool for the study of inequality.
      ,
      • van Ingen T.
      • Matheson F.I.
      The 2011 and 2016 iterations of the Ontario Marginalization Index: updates, consistency and a cross-sectional study of health outcome associations.
      and is widely used in health services research. We used the Ontario Marginalisation Database to assign each patient a dissemination area via the PCCF using their postal code on the day of diagnosis. Each patient was given a score, and then categorized into quintiles, with quintile 1 being the least deprived. Recent immigration was labeled as yes or no depending on whether the number of years from the date of landing to the diagnosis date was 5 years or less. Histology and tumor location were categorized. Stage was defined using the American Joint Committee on Cancer eighth edition.
      • Amin M.B.
      • Edge S.
      • Greene F.
      • Byrd D.R.
      • Brookland R.K.
      • Washington M.K.
      • et al.
      AJCC Cancer Staging Manual.
      First, we used the OCR to identify the best stage information for each patient. The OCR uses an algorithm that provides the stage from a pathological diagnosis if available. If no such diagnosis exists, the algorithm assigns stage on the basis of radiology results, followed by cancer center patient chart entries. Second, we created a separate stage variable for those with missing OCR stage using individual American Joint Committee on Cancer eighth edition T, N, and M categories from the Activity Level Reporting. Diagnosing physician characteristics included specialty (if there was more than one specialty then “mainspecialty” was used), years in practice, and academic affiliation. We operationalized health care utilization as the use of the emergency department (ED) and/or a hospital admission between diagnosis and treatment.

      Statistical Analyses

      Descriptive statistics were used to describe baseline demographic characteristics. We conducted bivariate analyses of each independent variable against the 50th and 90th percentile of the TI and subintervals using nonparametric tests. We used multivariable quantile regression models, adjusting simultaneously for patient factors, disease factors, treatment group, and LHIN. We used stage in the sensitivity analyses described in the following paragraph. All data processing and analyses were performed at ICES Queen's using the SAS software version 9.4 (SAS Institute Inc).
      We conducted 6 sensitivity analyses on the adjusted quantile regression analysis. The first removed LHIN from the original model to determine if LHIN-based patient characteristic variations had distorted the patient characteristic associations. For the second, third, and fourth, immigration and rurality, separately then combined, were removed from the original model to assess whether those variables influenced the LHIN effects. The fifth removed the treatment group from the original model to assess the independence of the other factors from treatment. Last, we added stage to the original model to assess its effect on those associations.

      Results

      Of 7822 patients diagnosed with esophageal cancer, 7509 patients had a recorded biopsy procedure, and 6042 received at least 1 treatment modality. After exclusions, the final study cohort comprised 5759 patients (Table 1). Most patients were male (77.6%), had a total ADG of between 4 and 6 (32.3%), were not recent immigrants (93.5%), lived in an urban area (84.6%), had adenocarcinoma (AC; 71.6%), and had lower esophagus (39.9%) or gastroesophageal junction (39.8%) tumors. Staging was as follows: I: 5.1%, II: 9.6%, III: 14.8%, IV: 23.9%, and missing: 46.7%. Gastroenterologists diagnosed the most cancers (41.3%). Chemoradiotherapy was the most common first treatment modality (26.8%).
      Table 1Patient, disease, diagnosing physician, health care system, and health care utilization characteristics of Ontario patients with esophageal cancer between 2013 and 2018
      Cohort characteristicNumber of patients (%)
      Age group, y
       18-49296 (5.1)
       50-591105 (19.1)
       60-691923 (33.3)
       70-791596 (27.6)
       ≥80855 (14.8)
      Sex
       Female1293 (22.4)
       Male4482 (77.6)
      Sum of minor AGDs
       0338 (5.9)
       1-21054 (18.2)
       3-41481 (25.7)
       5-61421 (24.6)
       ≥71481 (25.7)
      Sum of major ADGs
       02097 (36.3)
       11799 (31.2)
       21048 (18.2)
       ≥3831 (14.4)
      Total number of ADGs
       0288 (5.0)
       1-31346 (23.3)
       4-61866 (32.3)
       7-91309 (22.7)
       ≥10966 (16.7)
      Recent immigration
       No5401 (93.5)
       Yes374 (6.5)
      Material deprivation
       Least deprived1075 (18.6)
       21155 (20.0)
       31130 (19.6)
       41176 (20.4)
       Most deprived1198 (20.7)
       Unknown41 (0.7)
      Rurality
       Rural884 (15.3)
       Urban4885 (84.6)
       Unknown6 (0.1)
      Calendar year of diagnosis
       2013930 (16.1)
       2014892 (15.5)
       2015957 (16.6)
       2016948 (16.4)
       20171002 (17.4)
       20181046 (18.1)
      Histology
       Adenocarcinoma4133 (71.6)
       Squamous cell carcinoma1195 (20.7)
       Other447 (7.7)
      Tumor site
       Cervical esophagus94 (1.6)
       Upper esophagus192 (3.3)
       Middle esophagus564 (9.8)
       Lower esophagus2305 (39.9)
       Gastroesophageal junction2298 (39.8)
       Other322 (5.6)
      Stage
       I294 (5.1)
       II552 (9.6)
       III852 (14.8)
       IV1382 (23.9)
       Unknown2695 (46.7)
      Diagnosing physician main specialty
       Gastroenterology2384 (41.3)
       General surgery1777 (30.8)
       Thoracic surgery584 (10.1)
       Other554 (9.6)
       Unknown476 (8.2)
      Diagnosing physician years in practice
       1-9247 (4.3)
       10-14835 (14.5)
       15-19592 (10.3)
       20-24512 (8.9)
       25-29452 (7.8)
       ≥30451 (7.8)
       Unknown2686 (46.5)
      Diagnosing physician academic affiliation
       No3462 (60.6)
       Yes1484 (25.7)
       Unknown829 (14.4)
      LHIN of residence at diagnosis
       01345 (6.0)
       02523 (9.1)
       03323 (5.6)
       04832 (14.4)
       05246 (4.3)
       06375 (6.5)
       07374 (6.5)
       08496 (8.6)
       09674 (11.7)
       10307 (5.3)
       11517 (9.0)
       12281 (4.9)
       13353 (6.1)
       14129 (2.2)
      Treatment group
       Endoscopy with or without subsequent treatment543 (9.4)
       Chemotherapy only792 (13.7)
       Radiotherapy only1177 (20.4)
       Surgery with or without subsequent treatment571 (9.9)
       Chemotherapy and radiotherapy1550 (26.8)
       Chemotherapy or radiotherapy then surgery164 (2.8)
       Chemotherapy and radiotherapy then surgery733 (12.7)
       Other245 (4.2)
      ED visits between diagnosis and treatment
       04911 (85.0)
       1661 (11.4)
       >1203 (3.6)
      Hospital admissions between diagnosis and treatment
       04228 (73.2)
       11323 (22.9)
       >1224 (3.9)
      ADG, Aggregate diagnostic group; LHIN, Local Health Integration Network; ED, Emergency Department.

      Length of TI and Subintervals

      The median TI length was 36 days (interquartile range [IQR], 22-55 days) and the 90th percentile was 77 days (Figure 2). The subinterval 1 median length was 2 days (IQR, −3 to 10 days; 90th percentile, 20 days); the subinterval 2 median length was 34 days (IQR, 20-51 days; 90th percentile, 73 days).
      Figure thumbnail gr2
      Figure 2Box and whisker plot depicting the distribution of the Ontario esophageal cancer treatment interval between 2013 and 2018. Upper whisker = maximum observation excluding outliers; lower whisker = minimum observation excluding outliers; upper box bar = 75th percentile; lower box bar = 25th percentile; middle box bar = 50th percentile; dots = outliers (observations outside 1.5 times interquartile range).
      Geographical differences were seen (Figures 3 and 4, Table 2). The difference between the LHINs with the longest and shortest TI at the 50th and 90th percentile was 18 and 25 days, respectively. Except LHIN 14, all exhibited similar distributions of width and skew, suggesting similar variability within each LHIN. Both subinterval lengths differed across LHINs (P < .0001).
      Figure thumbnail gr3
      Figure 3Box and whisker plot showing the comparison of the esophageal cancer treatment interval length distribution among LHINs in Ontario between 2013 and 2018. Upper whisker = maximum observation excluding outliers; lower whisker = minimum observation excluding outliers; upper box bar = 75th percentile; lower box bar = 25th percentile; middle box bar = 50th percentile; dots = outliers (observations outside 1.5 times interquartile range). LHIN, Local Health Integration Network.
      Figure thumbnail gr4
      Figure 4Different distributions of the esophageal cancer treatment interval length among Local Health Integration Networks in Ontario between 2013 and 2018. Upper whisker = maximum observation excluding outliers; lower whisker = minimum observation excluding outliers; upper box bar = 75th percentile; lower box bar = 25th percentile; middle box bar = 50th percentile; dots = outliers (observations outside 1.5 times interquartile range).
      Table 2Lengths of the treatment interval, subinterval 1, and subinterval 2 at the 50th and 90th percentile according to category of associated factors in Ontario patients with esophageal cancer between 2013 and 2018
      VariableTreatment intervalSubinterval 1
      Subinterval 1 = diagnosis to first health care encounter.
      Subinterval 2
      Subinterval 2 = first health care encounter to treatment start.
      50th (IQR)90th50th (IQR)90th50th (IQR)90th
      Whole cohort36 (22-55)772 (−3 to 10)2034 (20-51)73
      LHINP < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       0133 (21-49)711 (−3 to 8)1832 (17-48)65
       0240 (23-57)824 (−2 to 12)2235 (20-54)79
       0340 (27-59)814 (−3 to 10)2038 (25-56)77
       0430 (19-48)712 (−5 to 9)2030 (17-47)65
       0539 (26-55)792 (−4 to 8)1937 (23-56)76
       0644 (27-63)931 (−2 to 9)2138 (24-59)89
       0737 (22-55)801 (−6 to 8)2037 (22-55)79
       0830 (16-49)683 (−2 to 11)2028 (14-44)65
       0937 (22-56)713 (−4 to 11)1934 (21-50)71
       1046 (29-63)827 (−1 to 15)2438 (22-55)75
       1142 (27-58)833 (−2 to 11)1939 (24-55)77
       1228 (17-41)691 (−3 to 10)2126 (14-40)70
       1335 (20-53)721 (−3 to 9)1834 (20-50)66
       1441 (26-60)882 (−4 to 8)1738 (26-53)77
      Age group, yP = .01P < .0001P = 1.00P = .002P < .0001P < .0001
       18-4930 (15-45)671 (−2 to 7)1428 (14-44)64
       50-5935 (21-54)733 (−3 to 9)1933 (19-49)69
       60-6936 (22-54)752 (−4 to 10)1935 (21-50)71
       70-7938 (23-57)803 (−4 to 11)2136 (22-54)76
       ≥8036 (20-58)843 (−2 to 11)2132 (16-53)78
      SexP = .30P = .37P = .07P = .37P = 1.00P = .25
       Female37 (22-55)753 (−3 to 11)2034 (19-50)70
       Male36 (22-55)782 (−3 to 10)1934 (20-51)75
      Sum of minor ADGsP < .0001P < .0001P = .0005P < .0001P < .0001P < .0001
       032 (17-49)670 (−3 to 7)1331 (17-48)63
       1-235 (21-51)712 (−3 to 9)1733 (20-49)65
       3-435 (22-53)752 (−2 to 10)1833 (19-48)70
       5-638 (23-57)803 (−3 to 11)2035 (21-54)76
       ≥739 (23-58)853 (−4 to 12)2435 (21-54)79
      Sum of major ADGsP = .009P < .0001P = .55P = .0006P = .11P < .0001
       035 (21-50)692 (−2 to 9)1633 (20-48)67
       136 (21-56)762 (−3 to 10)2034 (20-52)73
       238 (23-59)823 (−3 to 12)2235 (20-55)78
       ≥339 (22-62)872 (−4 to 13)2435 (20-56)79
      Total ADGsP < .0001P < .0001P = .05P < .0001P = .0015P < .0001
       033 (18-49)650 (−2 to 7)1333 (19-47)63
       1-334 (20-50)712 (−3 to 9)1632 (19-48)65
       4-637 (22-55)773 (−2 to 10)1934 (20-50)73
       7-937 (23-56)783 (−3 to 12)2135 (20-53)76
       ≥1040 (23-62)912 (−5 to 13)2536 (20-57)81
      Recent immigrationP = .64P = .25P = .14P = .35P = .08P = .28
       No36 (22-55)772 (−3 to 10)2034 (20-51)73
       Yes37 (21-56)831 (−5 to 9)1937 (20-54)79
      Material deprivationP = .49P = .88P = .73P = .69P = .09P = .06
       Least deprived36 (22-54)803 (−3 to 11)2034 (20-50)73
       236 (22-53)762 (−3 to 10)2133 (19-49)68
       336 (22-55)762 (−3 to 10)1935 (20-52)73
       436 (22-54)762 (−3 to 9)1933 (21-50)74
       Most deprived37 (22-58)802 (−3 to 11)2036 (20-55)76
      RuralityP = .46P = .16P = 1.00P = 1.00P = .16P = .13
       Rural37 (23-58)833 (−3 to 11)2035 (21-54)79
       Urban36 (21-54)762 (−3 to 10)2034 (20-50)71
      Year of diagnosisP = .56P = .98P = .31P = .55P = .48P = .82
       201336 (21-57)794 (−2 to 11)2134 (19-51)73
       201435 (21-53)762 (−3 to 9)1734 (20-50)73
       201536 (22-55)762 (−3 to 9)2034 (20-50)77
       201635 (20-55)782 (−4 to 11)2133 (20-51)74
       201738 (23-56)782 (−3 to 11)2035 (20-53)74
       201837 (22-54)772 (−3 to 10)1933 (21-49)71
      HistologyP = .02P = .11P < .0001P = .01P = .27P = .18
       Adenocarcinoma37 (22-56)793 (−2 to 11)2134 (20-51)75
       Squamous cell carcinoma35 (22-52)731 (−4 to 9)1834 (20-50)70
       Other29 (16-51)690 (−7 to 7)1532 (18-49)68
      Tumor siteP = .16P = .0006P < .0001P = .05P = .83P = .46
       Cervical esophagus34 (19-47)630 (−7 to 4)1634 (19-49)66
       Upper esophagus35 (23-52)812 (−3 to 10)1734 (21-49)77
       Middle esophagus37 (21-56)722 (−5 to 10)1934 (20-51)70
       Lower esophagus36 (22-55)753 (−2 to 10)1934 (20-50)72
       Gastroesophageal junction36 (22-56)812 (−3 to 11)2134 (20-52)76
       Other32 (19-53)760 (−8 to 9)1932 (18-53)75
      StageP < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       I48 (35-66)1017 (0-15)2742 (27-61)85
       II43 (29-60)795 (0-13)2137 (25-55)75
       III42 (27-57)754 (0-9)1837 (24-54)72
       IV28 (17-44)631 (−5 to 8)1428 (17-44)63
       Unknown36 (21-56)802 (−4 to 11)2334 (19-52)77
      SpecialtyP < .0001P = .07P < .0001P < .0001P < .0001P < .0001
       Gastroenterology37 (22-56)794 (0-12)2133 (18-50)73
       General surgery38 (24-56)774 (−1 to 11)1934 (21-50)70
       Thoracic surgery33 (18-49)77−7 (−19 to 0)841 (26-60)84
       Other29 (17-49)712 (−2 to 9)1928 (16-45)65
      Years in PracticeP = .14P = .0004P = .03P = .03P = .03P = .002
       1-937 (24-58)813 (−2 to 9)1936 (21-52)77
       10-1435 (22-51)702 (−4 to 9)1934 (21-49)68
       15-1938 (23-57)753 (−2 to 10)1835 (21-52)71
       20-2437 (23-56)824 (−3 to 12)2133 (21-51)73
       25-2935 (20-53)773 (−2 to 12)2131 (18-47)70
       ≥3037 (22-56)762 (−1 to 13)2234 (18-48)70
       Unknown36 (21-56)792 (−4 to 10)1934 (20-53)76
      Academic affiliationP = .08P = .26P < .0001P = .47P = .22P = .02
       No37 (22-55)773 (−1 to 11)2034 (20-50)70
       Yes35 (20-55)780 (−9 to 8)1935 (20-52)77
      Treatment group
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      P < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       A23 (14-36)505 (0-13)2116 (7-30)48
       B39 (24-60)870 (−7 to 8)1739 (26-57)79
       C29 (16-49)730 (−7 to 7)1529 (17-48)71
       D58 (38-82)1117 (−4 to 18)3150 (34-77)101
       E36 (22-55)742 (−3 to 9)1834 (21-50)67
       F40 (26-54)633 (−1 to 10)2035 (21-48)65
       G40 (28-52)645 (0-11)1835 (26-48)59
       H39 (26-50)638 (0-15)3528 (14-42)60
      ED visitsP < .0001P < .0001P = .10P = 1.0000P < .0001P < .0001
       035 (21-52)732 (−3 to 10)2033 (19-48)69
       145 (26-67)912 (−3 to 9)2042 (24-62)91
       >154 (31-76)991 (−5 to 7)1948 (31-72)98
      Hospital admissionsP = .004P < .0001P < .0001P < .0001P < .0001P < .0001
       036 (22-54)764 (−3 to 12)2133 (20-49)70
       135 (20-56)791 (−3 to 6)1435 (20-54)76
       >148 (29-73)1060 (−5 to 3)1348 (32-71)109
      50th, 50th percentile; IQR, interquartile range; 90th, 90th percentile; LHIN, Local Health Integration Network; ADG, Aggregate Diagnostic Group; ED, Emergency Department.
      Subinterval 1 = diagnosis to first health care encounter.
      Subinterval 2 = first health care encounter to treatment start.
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      Differences remained between LHINs after adjusting for confounding. The biggest change was seen in LHIN 12, which had a 5-day longer median TI (−11 to −6 days longer than the referent group). The remainder demonstrated change of 3 days or less in median TI, suggesting minimal confounding by other covariates in those LHINs.

      Bivariate Analysis of Associated Factors

      Younger patients (18-49 years) had shorter median TIs than older patients (70-79 years); 30 days (IQR, 15-45) versus 38 days (IQR, 23-57 days; P = .01). Those with a total ADG score of ≥10 waited a median of 40 days (IQR, 23-62 days) versus 33 days (IQR, 18-49 days) for those with no comorbidity. The median TI did not differ statistically on the basis of sex (P = .30), immigration (P = .64), rurality (P = .46), nor deprivation (P = .49).
      Those with histology other than AC or squamous cell carcinoma (SCC) had a shorter median TI (29 days; IQR, 16-51 days) than those with AC (37 days; IQR, 22-56 days) or SCC (35 days; IQR, 22-52 days). Cancer stage was inversely proportional to the median and 90th percentile of the TI length; stage I, 48 days (IQR, 35-66 days) versus stage IV, 28 days (IQR, 17-44 days; P < .0001).
      Patients diagnosed by a thoracic surgeon had a shorter median TI; 33 days (IQR, 18-49 days) compared with those diagnosed by a general surgeon; 38 days (IQR, 24-56 days) or gastroenterologist; 37 days (IQR, 22-56 days). However, those diagnosed by a physician in the “other” category had the shortest median (29 days) and the 90th percentile (71 days) TI. There was no statistical difference in median TI regarding the number of years the diagnosing physician had been in practice (P = .13), however there was a difference at the 90th percentile (P = .0004; 10-14 years, 70 days vs 20-24 years, 82 days). Academic affiliation was not associated with the median (P = .08) or 90th percentile (P = .26) TI length. The median and 90th percentile TI was longer in patients who had one or more ED visits or hospital admissions between diagnosis and treatment; >1 ED visit, 54 days (IQR, 31-76 days) versus 0 ED visits, 35 days (IQR, 21-52 days); >1 admission, 48 days (IQR, 29-73 days) versus 0 admissions, 36 days (IQR, 22-54 days).

      Adjusted Regression Analysis of Associated Factors

      In the adjusted models (Table 3), age, comorbidity, deprivation, rurality, histology, and LHIN were associated with statistical differences in the median TI length. There was a 9-day difference in the age variable between those with the longest (≥80 years old) and shortest TI (18-49 years old). The remainder of the variables that showed statistical adjusted differences had differences of <5 days.
      Table 3Unadjusted and adjusted differences of the treatment interval at the 50th and 90th percentile according to category in Ontario patients with esophageal cancer between 2013 and 2018
      Variable50th Percentile90th Percentile
      Unadjusted difference (95% CI)Adjusted difference (95% CI)Unadjusted difference (95% CI)Adjusted difference (95% CI)
      Adjusted intercept38 (35-42)55 (45-65)
      AgeP = .03P < .0001P < .0001P = .03
       Unadjusted intercept37 (35-38)75 (72-78)
       18-49−3 (−7 to 1)−7 (−10 to −4)−10 (−19 to −1)−6 (−14 to 2)
       50-59−1 (−3 to 1)−2 (−3 to 0)1 (−5 to 7)2 (−2 to 6)
       60-69ReferentReferentReferentReferent
       70-793 (0-6)2 (1-4)7 (2-12)4 (0-7)
       ≥800 (−3 to 3)2 (0-5)11 (5-17)6 (0-12)
      SexP = .31P = .69P = .35P = .96
       Unadjusted intercept38 (36-40)77 (73-81)
       FemaleReferentReferentReferentReferent
       Male−1 (−3 to 1)0 (−1 to 2)2 (−2 to 6)0 (−4 to 4)
      Sum of minor ADGsP < .0001P = .0005P < .0001P = .39
       Unadjusted intercept35 (34-36)71 (67-75)
       0-2ReferentReferentReferentReferent
       3-40 (−2 to 2)0 (−2 to 2)4 (−2 to 10)2 (−2 to 6)
       5-65 (3-7)3 (1-5)9 (3-15)3 (−1 to 8)
       ≥75 (3-7)3 (1-6)15 (9-21)4 (−1 to 9)
      Sum of major ADGsP = .02P = .70P < .0001P = .003
       Unadjusted intercept36 (35-40)71 (68-74)
       0ReferentReferentReferentReferent
       11 (−1 to 3)1 (−1 to 2)7 (3-11)4 (0-8)
       22 (−1 to 5)1 (−1 to 4)12 (6-18)8 (3-13)
       ≥34 (1-7)1 (−1 to 3)17 (11-24)11 (4-17)
      Material deprivationP = .33P = .001P = .78P = .005
       Unadjusted intercept36 (34-38)80 (75-85)
       1ReferentReferentReferentReferent
       20 (−2 to 2)1 (−1 to 4)−4 (−12 to 4)−3 (−8 to 2)
       31 (−1 to 3)3 (1-6)−2 (−9 to 5)1 (−4 to 6)
       41 (−1 to 3)3 (1-5)−2 (−8 to 4)2 (−4 to 7)
       53 (−0 to 6)4 (2-7)0 (−7 to 7)5 (0-11)
      RuralityP = .45P = .04P = .15P = .04
       Unadjusted intercept37 (36-38)78 (75-80)
       UrbanReferentReferentReferentReferent
       Rural1 (−2 to 4)2 (0 to 4)5 (−2 to 12)6 (0-11)
      Recent immigrationP = .62P = .15P = .27P = .78
       Unadjusted intercept37 (36-38)78 (76-80)
       NoReferentReferentReferentReferent
       Yes1 (−3 to 4)2 (−1 to 5)5 (−4 to 14)1 (−6 to 8)
      HistologyP = .007P = .02P = .15P = .23
       Unadjusted intercept38 (37-39)80 (78-82)
       AdenocarcinomaReferentReferentReferentReferent
       Squamous cell carcinoma−1 (−3 to 1)−1 (−3 to 2)−5 (−10 to 0)−4 (−9 to 1)
       Other−6 (−10 to −2)−5 (−8 to −2)−3 (−11 to 5)−2 (−8 to 5)
      Tumor locationP = .19P = .22P = .0007P = .10
       Unadjusted intercept37 (36-38)83 (80-86)
       Cervical esophagus−3 (−11 to 5)−3 (−9 to 3)−12 (−26 to 2)−9 (−23 to 4)
       Upper esophagus−2 (−5 to 1)0 (−4 to 4)−8 (−21 to 5)−3 (−15 to 18)
       Middle esophagus0 (−3 to 3)1 (−2 to 4)−10 (−17 to 3)−1 (−9 to 6)
       Lower esophagus0 (−2 to 2)−1 (−2 to 1)−8 (−12 to −4)−4 (−8 to 0)
       Gastroesophageal junctionReferentReferentReferentReferent
       Other−5 (−9 to −1)−3 (−6 to 0)−0 (−12 to 12)4 (−6 to 13)
      LHINP < .0001P < .0001P = .0002P < .0001
       Unadjusted Intercept39 (36-41)78 (72-84)
       01−6 (−10 to −2)−6 (−10 to −2)−4 (−14 to 6)−9 (−17 to 1)
       020 (−3 to 4)−2 (−5 to 1)4 (−6 to 14)−2 (−11 to 6)
       033 (0-7)3 (−1 to 7)3 (−5 to 11)−1 (−8 to 6)
       04−7 (−10 to −3)−8 (−11 to −5)−7 (−15 to 1)−12 (−18 to −7)
       050 (−4 to 5)−2 (−7 to 2)0 (−18 to 18)−1 (−10 to 9)
       065 (1-9)4 (0-8)14 (2-26)7 (−1 to 16)
       07−1 (−4 to 3)−2 (−6 to 1)3 (−8 to 14)−3 (−11 to 4)
       08−4 (−8 to 0)−4 (−7 to −1)−1 (−11 to 9)−3 (−10 to 4)
       09ReferentReferentReferentReferent
       107 (3-11)6 (1-11)2 (−8 to 16)−2 (−10 to 5)
       113 (−1 to 7)2 (0 to 5)5 (−2 to 12)−1 (−9 to 7)
       12−11 (−14 to −7)−6 (−9 to −2)−7 (−19 to 5)−2 (−12 to 8)
       13−5 (−8 to −2)−8 (−12 to −5)−7 (−16 to 2)−12 (−18 to −6)
       141 (−5 to 7)1 (−5 to 3)11 (−4 to 26)−9 (−19 to 1)
      Treatment group
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      P < .0001P < .0001P < .0001P < .0001
       Unadjusted Intercept41 (39-43)64 (60-68)
       A−17 (−20 to −14)−16 (−19 to −14)−9 (−18 to −1)−16 (−22 to −10)
       B0 (−3 to 3)0 (−3 to 3)27 (20-34)21 (14-27)
       C−10 (−13 to −7)−11 (−13 to −8)13 (7-19)6 (0-13)
       D15 (12-18)15 (12-18)45 (35-55)37 (29-44)
       E−4 (−7 to −2)−3 (−5 to −1)10 (5-15)8 (4-12)
       F−1 (−6 to 4)−2 (−7 to 3)−3 (−13 to 7)0 (−9 to 9)
       GReferentReferentReferentReferent
       H−2 (−6 to 2)−2 (−5 to 2)0 (−8 to 8)−4 (−10 to 2)
      CI, Confidence interval; ADG, Aggregate Diagnostic Group; LHIN, Local Health Integration Network.
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      At the 90th percentile, age, comorbidity, material deprivation, rurality, LHIN, and treatment group were associated with differences in the TI length. Those who underwent endoscopic resection (alone or initially) waited 53 days less for treatment compared with those who underwent surgery (alone or initially). Patients aged ≥80 years waited 12 days longer for treatment than those aged 18-49 years old. Those with 3 or more comorbidities waited 11 days longer than those without any comorbidities. Patients living in the most materially deprived areas waited 6 days longer than those in the least deprived areas, and those in rural locations waited 6 days longer than their urban counterparts. Rurality and material deprivation variables became significant in the adjusted analysis at both percentiles.

      Sensitivity Analyses

      At the 50th percentile, only the exclusion of LHIN and immigration affected other variables, resulting in rurality no longer being significant compared with the original model (Table E4). At the 90th percentile, in 4 of the 6 sensitivity analyses, deprivation and rurality became insignificant, whereas number of minor comorbidities and disease histology and site became significant. The addition of stage resulted in age and rurality no longer being significant but did not affect other variables (Table E5).

      Discussion

      The key finding of this study was an absolute difference of 18 and 25 days between the LHINs with the longest and shortest median and 90th percentiles, respectively. Furthermore, we identified those who are older, more comorbid, and diagnosed by a physician other than a thoracic surgeon to be vulnerable patient populations that might be more at risk of a prolonged TI.
      In contrast to our results, in one Ontario study
      • Habbous S.
      • Yermakhanova O.
      • Forster K.
      • Holloway C.M.B.
      • Darling G.
      Variation in diagnosis, treatment, and outcome of esophageal cancer in a regionalized care system in Ontario, Canada.
      it was reported that the median time to treatment was 46 days (IQR, 29-66 days) in 79% of their patients. Our cohorts were created differently, which might explain the difference. We labeled the day of diagnosis as the date of endoscopic biopsy if one was available (>80%), and the date of diagnosis in the OCR otherwise, whereas those authors used the OCR date as the day of diagnosis for all. In an older study
      • Bardell T.
      • Belliveau P.
      • Kong W.
      • Mackillop W.J.
      Waiting times for cancer surgery in Ontario: 1984-2000.
      a median wait time from esophageal cancer diagnosis to surgery of 32 days, was reported, but that study's cohort was restricted only to patients who underwent surgery, and the study period was 1984 to 2000, which preceded the provincial regionalization of thoracic cancer services. In contrast, our cohort included patients who had treatment modalities other than surgery. This difference might explain why our median TI was shorter, because the patients in our study who underwent surgery first had a longer TI than those who had another treatment before surgery. A more recent study from the United States
      • Raman V.
      • Jawitz O.K.
      • Voigt S.L.
      • Yang C.J.
      • Wang H.
      • Harpoon D.
      • et al.
      Effect of time to surgery on outcomes in stage I esophageal adenocarcinoma.
      calculated a median time to surgery of 54 days in patients with cT1N0M0 esophageal carcinoma who underwent surgery from 2004 to 2015. This also corroborates our findings that patients with an early-stage cancer, or patients having surgery as their first treatment modality, have a longer TI than others.
      We found variability across LHINs in all time intervals, at the 50th and 90th percentile. The goal of regionalization was to provide optimal patient care for those who require specialist services, regardless of their location in the province.
      • Darling G.E.
      Regionalization in thoracic surgery: the importance of the team.
      An Ontario study from 2013
      • Sundaresan S.
      • McLeod R.
      • Irish J.
      • Burns J.
      • Hunter A.
      • Meertens E.
      • et al.
      Early results after regionalization of thoracic surgical practice in a single-payer system.
      demonstrated that median wait times for lung cancer treatment did not shorten over the period from 2007 to 2011, but there was a reduction in 30-day mortality after pneumonectomy. All LHINs have a thoracic center located within their borders except one. One LHIN contains 3 thoracic centers. Neither of these 2 LHINs had the shortest or longest TI, suggesting the difference is explained by factors other than regionalization. Our sensitivity analyses (Tables E4 and E5) showed persistent LHIN differences at the 50th and 90th percentiles, suggesting there might be systemic inefficiencies meriting further study. Table E6 shows the distribution of patient factors within each LHIN.
      At the 50th percentile, older, more comorbid, nonurban, and patients living in the most deprived areas waited up to 9 days, 3 days, 2 days, and 4 days longer than their counterparts, respectively. These differences were greater at the 90th percentile (12 days, 11 days, 6 days, and 5 days, respectively). Despite being statistically significant, these differences might not be clinically meaningful on survival
      • DE Rosa M.
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      but they likely affect patient anxiety levels
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      Quality of life in newly diagnosed cancer patients waiting for surgery is seriously impaired.
      and symptom progression. These associations are consistent with previously published literature on other cancer sites. Gillis and colleagues
      • Gillis A.
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      A patient-centred approach toward surgical wait times for colon cancer: a population-based analysis.
      reported that older patients, those living in rural areas, and those with a lower income had a longer wait time to colorectal cancer surgery in Ontario than others. Kulkarni and colleagues
      • Kulkarni G.S.
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      Longer wait times increase overall mortality in patients with bladder cancer.
      also reported that older age and more severe comorbidity burden were associated with a longer wait time for urology cancer treatment. Bardell and colleagues
      • Bardell T.
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      • Mackillop W.J.
      Waiting times for cancer surgery in Ontario: 1984-2000.
      also reported that increasing age, decreasing household income, and female sex were predictors of longer wait times between diagnosis and surgery for a cohort comprised of 12 different cancers, but did not stratify their analysis on the basis of cancer type. Possible reasons for differences according to patient characteristics have been postulated. Elderly patients might have more missed or rescheduled appointments, which might contribute to a longer TI.
      • Macleod U.
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      Those living in rural locations might struggle to keep appointments that require a long travel distance.
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      Risk factors for delayed presentation and referral of symptomatic cancer: evidence for common cancers.
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      Patients living in an area of higher material deprivation, which we used as a surrogate for individual-level socioeconomic status, might miss appointments because of difficulty getting time off work or paying for transport to their appointments.
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      Risk factors for delay in symptomatic presentation: a survey of cancer patients.
      Many previous studies have restricted their cohorts to patients with AC or SCC.
      • Raman V.
      • Jawitz O.K.
      • Voigt S.L.
      • Yang C.J.
      • Wang H.
      • Harpoon D.
      • et al.
      Effect of time to surgery on outcomes in stage I esophageal adenocarcinoma.
      ,
      • Grotenhuis B.A.
      • van Hagen P.
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      Delay in diagnostic workup and treatment of esophageal cancer.
      • Kötz B.S.
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      Do delays between diagnosis and surgery in resectable oesophageal cancer affect survival? A study based on West Midlands cancer registration data.
      • Visser E.
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      • Ruurda J.P.
      Impact of diagnosis-to-treatment waiting time on survival in esophageal cancer patients – a population-based study in The Netherlands.
      • Wang J.
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      • Wei W.
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      • et al.
      The symptom-to-treatment delay and stage at the time of treatment in cancer of esophagus.
      It is unclear why histological subtypes other than AC or SCC would have a shorter TI. Rare diagnoses are more likely to be brought to the multidisciplinary team for discussion and this might expedite pretreatment investigations and specialist visits. Patients with a stage IV cancer had a TI that was 20 days shorter than those with a stage I cancer. At the 90th percentile, this difference increased to 38 days. Previous studies conducted in Ontario have shown the same phenomenon in other cancer sites.
      • Plotogea A.
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      Factors associated with wait times across the breast cancer treatment pathway in Ontario.
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      Breast cancer diagnosis and treatment wait times in specialized diagnostic units compared with usual care: a population-based study.
      • Siemens D.R.
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      A population-based study of the waiting times for prostatectomy in Ontario.
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      Addressing wait times for endometrial cancer surgery in Ontario.
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      • Seow H.
      The wait time creep: changes in the surgical wait time for women with uterine cancer in Ontario, Canada, during 2000-2009.
      Large population studies from the United States have also shown the same effect in a range of different solid organ cancers.
      • Bilimoria K.Y.
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      • et al.
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      ,
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      Possible explanations exist. First, patients with a later stage are more likely to have symptoms from their disease than those with early-stage cancers. At the system level, symptomatic patients might have their investigations and specialist visits expedited because of the concerning symptom severity. Second, there might be a lower sense of urgency with lower-stage cancers, and in a resource-constrained health care system, those with a higher stage will likely take priority for investigations and treatment. Third, possible treatment options vary between stage I and stage IV. Most stage IV patients will undergo palliative treatment that does not include surgery.
      • Akhtar-Danesh N.
      • Shakeel S.
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      Trends in survival based on treatment modality for esophageal cancer: a population-based study.
      Our results have shown that patients who are receiving radiotherapy alone have a much shorter TI length than those who undergo surgery.
      Patients diagnosed by a thoracic surgeon had a shorter TI than those diagnosed by a gastroenterologist or a general surgeon. Those latter patients will be referred to a thoracic surgeon for a consultation; patients diagnosed by a thoracic surgeon might have that consultation at the same time as the diagnosis, thereby skipping a step on the clinical pathway and shortening the interval.
      Patients who had one or more ED visits or hospital admissions between diagnosis and treatment had a longer median TI than those who had neither. These patients might have been too sick to undergo their cancer treatment and require treatment of the illness that prompted the ED visit or admission first.

      Strengths and Limitations

      To our knowledge, this is the first Ontario-wide population-level study to include such an extensive number of risk factors for a prolonged TI including the assessment of its geographical variation. Previous Ontario studies were either performed on a heterogenous cohort of cancer patients
      • Bardell T.
      • Belliveau P.
      • Kong W.
      • Mackillop W.J.
      Waiting times for cancer surgery in Ontario: 1984-2000.
      or did not assess differences in TI length according to geography.
      • Habbous S.
      • Yermakhanova O.
      • Forster K.
      • Holloway C.M.B.
      • Darling G.
      Variation in diagnosis, treatment, and outcome of esophageal cancer in a regionalized care system in Ontario, Canada.
      By partitioning the TI into 2 distinct subintervals, we also identified other potentially modifiable risk factors that were not present on analysis of the overall TI. We used routinely collected health administrative data that allowed us to study the entire esophageal cancer population in Ontario during our time frame. Mandatory submissions from all hospitals in the province to CIHI and NACRS decreases the likelihood of institutions being over-represented. Our definition of the diagnosis date is more refined than in previous studies that used the cancer registry date as the diagnosis date. We used the date of endoscopic biopsy to create a TI definition that was as accurate as possible, and is in line with national efforts to standardize time intervals.
      • Winget M.
      • Turner D.
      • Tonita J.
      • King C.
      • Nugent Z.
      • Alvi R.
      • et al.
      Across-province standardization and comparative analysis of time-to-care intervals for cancer.
      Last, our results are generalizable to other countries because we have found specific patient groups more at risk of longer intervals that transcend geography. Although the magnitude of differences might be specific to Ontario, the wait time variation is unlikely to be on clinical grounds and is generalizable to regions with similar health care models.
      Stage was only 54% complete despite capturing data from several databases. A recent study using the same databases
      • Habbous S.
      • Yermakhanova O.
      • Forster K.
      • Holloway C.M.B.
      • Darling G.
      Variation in diagnosis, treatment, and outcome of esophageal cancer in a regionalized care system in Ontario, Canada.
      had similar completeness. The sensitivity analysis that included stage showed that stage had no effect on the association of the other variables at the 50th percentile. The unknown group had a longer TI than stage IV patients, but shorter than the others (stage I-III) and are likely to be stage IV patients, receive nonsurgical treatment,
      • Habbous S.
      • Yermakhanova O.
      • Forster K.
      • Holloway C.M.B.
      • Darling G.
      Variation in diagnosis, treatment, and outcome of esophageal cancer in a regionalized care system in Ontario, Canada.
      and were equal across all LHINs. There was uncontrolled confounding by using administrative databases. Patient factors not included that might have affected the TI length include a patient's social situation (eg, access to reliable public transportation).

      Conclusions

      To our knowledge, this population-level study is the first to investigate the esophageal cancer TI length across different LHINs and examine numerous factors. We identified geographical variation despite adjusting for several factors. Patients who are older, more comorbid, or in rural areas are at greater risk for protracted wait times. Future research will be aimed at investigating an association between wait times and survival in our study population.

      Conflict of Interest Statement

      The authors reported no conflicts of interest.
      The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
      Parts of this material are on the basis of data and information compiled and provided by CIHI, Ontario Health, and Immigration, Refugees and Citizenship Canada current to May 2017. The analyses, conclusions, opinions, statements, results, and views expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred.

      Appendix E1

      Table E1Health administrative databases used in this study to obtain demographic, disease, billing, and outcomes data
      DatabaseDescription
      Ontario Cancer RegistryCancer information, including site, histology, and diagnosis date
      Registered Persons DatabasePatient demographic data including age, sex, vital status, and dates of last health care encounter
      Ontario Health Insurance Plan DatabasePhysician billing database for inpatient and outpatient services, including diagnoses, services provided, and dates
      Discharge Abstract DatabaseMandatory submissions from hospitals to the Canadian Institute for Health Information; includes information on hospital admission such as dates and diagnoses
      Same Day Surgery DatabaseStores information such as date and service for same-day procedures
      National Ambulatory Care Reporting DatabaseReceives mandatory submissions from institutions for visits made to hospital and community ambulatory care centers
      PCCFConverts a patient's postal code into a dissemination area to ascribe certain characteristics to each patient such as rurality and median household income
      Activity Level ReportingStores information on chemotherapy and radiotherapy dates and services, at regional centers and outreach clinics
      LHINStores information including population and number and type of hospitals within each LHIN
      Ontario MarginalisationThis database comprises separate elements (eg, material deprivation) and is used in conjunction with PCCF to assign patients a score
      IRCC Permanent Resident DatabaseThis includes information on people who applied to land in Ontario such as country of citizenship and date of landing
      ICES Physician DatabaseDemographic information on Ontario physicians including age, specialty, location of work, and year of graduation
      PCCF, Postal Code Conversion File; LHIN, Local Health Integration Network; IRCC, Immigration, Refugees, and Citizenship Canada; ICES, Institute for Clinical Evaluative Sciences.
      Table E2ICD-O-3 codes for morphology and topography
      DescriptionCode
      Adenocarcinoma8140-8141, 8143-8145, 8190-8231, 8260-8263, 8310, 8401, 8480-8490, 8550-8551, 8570-8574, 8576
      Squamous cell carcinoma8050-8078, 8083-8084
      Other80001-80003, 80103, 80203, 80223, 80303, 80313, 81482, 81490, 84903, 85603
      C15.0Cervical esophagus
      C15.1Thoracic esophagus
      C15.2Abdominal esophagus
      C15.3Upper third of esophagus
      C15.4Middle third of esophagus
      C15.5Lower third of esophagus
      C15.8Overlapping lesion of esophagus
      C15.9Esophagus, NOS
      C16.0Cardia, NOS
      • Gastric cardia
      • Cardioesophageal junction
      • Esophagogastric junction
      Gastroesophageal junction
      NOS, Not otherwise specified.
      Table E3Codes for diagnosis, consultations, investigations, and treatment
      EventCodeData source
      Biopsy2NA71, 2NC70BNCCI
      Z515, Z399, +E702OHIP fee
      150OHIP diagnosis code
      Consultations
      SurgeryA643-A646, C643-C646, W645, W646OHIP
      Medical oncologyA441-A448, A845, C441-C446, C845, W445, W446, W842-W847
      Radiation oncologyA340-A348, A745, C341-C346, C745
      Investigations
      CT (C/A/P)X125, X406, X407/X126, X409, X410/X231, X232, X233OHIP
      CT (head)X188, X400, X401, X402, +E874
      PETJ710
      EUSS236, E800
      PFTsJ301, J303, J304, J305, J306, J308, J310, J311, J324, J327, J340
      Treatment
      Endoscopic resectionS093, Z527, +E674/E675OHIP
      ChemotherapyG281, G339, G345, G359, G381, G382
      Radiotherapy519, 530-542, 548, 549, 575, 592, 594, 596, 597ALR
      SurgeryX310-X313OHIP
      1NA87-1NA92CCI
      S089, S090OHIP
      CCI, Canadian Classification of Health Information; OHIP, Ontario Health Insurance Plan; CT, computed tomography; C/A/P, chest, abdomen, pelvis; PET, positron emission tomography; EUS, endoscopic ultrasound; PFT, pulmonary function test; ALR, Activity Level Reporting.
      Table E4Comparison of original model with SA
      Original modelSA.1
      SA.1 = removal of LHIN.
      SA.2
      SA.2 = removal of immigration.
      SA.3
      SA.3 = removal of rurality.
      SA.4
      SA.4 = removal of immigration and rurality.
      SA.5
      SA.5 = removal of treatment group.
      SA.6
      SA.6 = addition of stage.
      Adjusted intercept38 (35-42)37 (34-40)38 (34-42)38 (35-42)38 (34-42)35 (31-39)41 (37-46)
      AgeP < .0001P < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       18-49−7 (−10 to −4)−6 (−10 to 13)−7 (−10 to 5)−7 (−10 to −5)−7 (−10 to −5)−5 (−8 to −2)−6 (−9 to −3)
       50-59−1 (−4 to 0)−2 (−4 to 0)−2 (−4 to 0)−2 (−4 to 0)−2 (−4 to 1)−2 (−4 to 0)−1 (−3 to 1)
       60-69ReferentReferentReferentReferentReferentReferentReferent
       70-792 (1-4)3 (1-4)2 (0-4)2 (1-4)3 (1-4)2 (0-4)2 (0-3)
       ≥802 (0-5)3 (1-6)2 (−1 to 4)2 (0-5)2 (−1 to 5)−1 (−4 to 2)3 (0-5)
      SexP = .70P = .81P = .79P = .80P = .82P = .91P = .39
       FemaleReferentReferentReferentReferentReferentReferentReferent
       Male0 (−1 to 2)0 (−2 to 2)0 (−2 to 2)0 (−1 to 2)0 (1−2)1 (−2 to 2)2 (−1 to 2)
      Sum of minor ADGsP = .0005P = .0005P = .004P = .0002P = .001P = .0006P = .0007
       0-2ReferentReferentReferentReferentReferentReferentReferent
       3-40 (−2 to 2)−1 (−3 to 2)0 (−2 to 2)0 (−2 to 2)0 (−2 to 2)0 (−2 to 2)0 (−2 to 2)
       5-63 (1-5)3 (1-5)3 (1-5)3 (1-5)3 (1-5)3 (1-5)3 (2-6)
       ≥74 (1-6)3 (1-6)3 (1-6)3 (1-5)3 (1-5)3 (1-6)3 (1-5)
      Sum of major ADGsP = .70P = .97P = .58P = .57P = .34P = .30P = .62
       0ReferentReferentReferentReferentReferentReferentReferent
       101 (−1 to 2)0 (−2 to 2)1 (−1 to 3)0 (−2 to 2)0 (−2 to 2)1 (−1 to 2)1 (−1 to 2)
       21 (−1 to 4)0 (−2 to 3)1 (−1 to 4)1 (−1 to 4)2 (0-4)2 (0-4)1 (−1 to 3)
       ≥31 (−1 to 3)1 (−2 to 3)1 (−1 to 4)1 (−1 to 3)2 (−1 to 4)2 (−1 to 5)1 (−2 to 3)
      Material deprivationP = .001P = .003P = .002P = .003P = .0008P = .009P = .002
       1ReferentReferentReferentReferentReferentReferentReferent
       21 (−1 to 4)2 (−1 to 4)1 (−1 to 3)1 (−1 to 4)1 (−1 to 4)0 (−2 to 3)1 (−2 to 3)
       33 (1-6)3 (1-5)3 (1-6)4 (1-6)4 (1-6)2 (−1 to 4)3 (1-5)
       43 (1-5)3 (1-5)3 (1-5)3 (1-5)3 (1-5)2 (0-5)2 (0-5)
       54 (2-7)4 (2-6)4 (2-6)4 (2-6)4 (2-6)4 (2-6)4 (2-6)
      RuralityP = .04P = .09P = .10P = .05P = .02
       UrbanReferentReferentReferentReferentReferent
       Rural2 (0-4)2 (0-4)2 (0-4)2 (0-4)2 (0-4)
      Recent immigrationP = .15P = .12P = .23P = .66P = .50
       NoReferentReferentReferentReferentReferent
       Yes2 (−1 to 5)2 (−1 to 5)2 (−1 to 5)1 (−2 to 4)1 (−2 to 4)
      HistologyP = .02P = .0001P = .02P = .01P = .02P = .0006P = .02
       AdenocarcinomaReferentReferentReferentReferentReferentReferentReferent
       Squamous cell carcinoma−1 (−3 to 2)−1 (−3 to 1)−1 (−3 to 2)−1 (−3 to 1)−1 (−3 to 1)−2 (−4 to 1)−1 (−3 to 1)
       Other−5 (−8 to −2)−6 (−8 to −3)−5 (−8 to −1)−5 (−8 to −2)−5 (−8 to −1)−6 (−10 to −3)−4 (−7 to −1)
      Tumor siteP = .22P = .55P = .28P = .30P = .23P = .10P = .48
       Cervical esophagus−3 (−9 to 3)−1 (−8 to 6)−3 (−8 to 3)−2 (−8 to 4)−3 (−8 to 3)−3 (−9 to 3)−5 (−11 to 1)
       Upper esophagus0 (−4 to 4)1 (−3 to 6)1 (−3 to 4)0 (−3 to 4)1 (−3 to 4)−2 (−7 to 3)−1 (−4 to 3)
       Middle esophagus1 (−2 to 4)0 (−2 to 4)1 (−2 to 4)1 (−2 to 4)1 (−2 to 4)1 (−2 to 4)1 (−2 to 4)
       Lower esophagus−1 (−2 to 1)1 (−1 to 2)−1 (−2 to 1)−0 (−2 to 1)−1 (−2 to 1)−1 (−3 to 1)−0 (−2 to 1)
       Gastroesophageal junctionReferentReferentReferentReferentReferentReferentReferent
       Other−3 (−6 to 0)−2 (−5 to 1)−3 (−6 to 1)−3 (−6 to 0)−3 (−6 to 1)−4 (−8 to −1)−2 (−5 to 1)
      LHINP < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       01−6 (−10 to −2)−6 (−10 to −3)−6 (−10 to −3)−6 (−10 to −3)−5 (−9 to −2)−6 (−9 to −2)
       02−2 (−5 to 1)−1 (−5 to 2)−1 (−4 to 2)−1 (−5 to 2)1 (−2 to 4)−4 (−7 to −1)
       033 (−1 to 7)3 (−1 to 8)4 (−1 to 7)3 (−1 to 7)5 (1-9)1 (−3 to 5)
       04−8 (−11 to −5)−8 (−11 to −5)−8 (−11 to 5)−8 (−11 to −5)−5 (−8 to −2)−8 (−10 to −5)
       05−2 (−7 to 2)−2 (−7 to 2.0)−2 (−7 to 2)−2 (−7 to 2)1 (−3 to 5)−2 (−6 to 3)
       064 (0-8)4 (0-8)4 (1-8)4 (1-8)8 (4-12)4 (0-8)
       07−2 (−6 to 1)−2 (−6 to 1)−2 (−6 to 1)−2 (−5 to 1)1 (−2 to 5)−4 (−7 to −0)
       08−4 (−7 to −1)−4 (−7 to 0)−4 (−8 to −1)−4 (−7 to −1)−3 (−7 to 1)−4 (−8 to −1)
       09ReferentReferentReferentReferentReferentReferent
       106 (1-11)6 (0-10)6 (1-11)6 (1-11)8 (4-13)5 (1-8)
       113 (0-5)3 (−1 to 6)3 (0-6)3 (0-6)5 (2-9)1 (−2 to 4)
       12−6 (−9 to −2)−6 (−9 to −2)−5 (−8 to −2)−5 (−9 to −2)−10 (−13 to −6)−6 (−10 to −3)
       13−8 (−12 to −5)−8 (−12 to −5)−8 (−11 to −4)−8 (−11 to −4)−4 (−8 to −1)−8 (−11 to −5)
       141 (−5 to 3)−1 (−6 to 4)−1 (−6 to 4)−1 (−6 to 4)3 (−3 to 9)−2 (−7 to 4)
      Treatment group
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      P < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       A−16 (−19 to 14)−18 (−20 to 15)−16 (−18 to 14)−16 (−19 to 13)−16 (−18 to −13)−12 (−15 to −10)
       B0 (−3 to 3)1 (−2 to 4)0 (−3 to 3)0 (−3 to 3)0 (−3 to 3)6 (3-9)
       C−11 (−13 to −8)−11 (−14 to −9)−11 (−13 to −8)−11 (−14 to −9)−11 (−14 to −9)−5 (−8 to −2)
       D15 (12-18)14 (11-17)15 (11-19)14 (11-18)15 (11-19)17 (13-20)
       E−3 (−5 to −1)−4 (−6 to −2)−3 (−5 to −1)−3 (−5 to −1)−3 (−5 to −2)1 (−1 to 3)
       F−2 (−7 to 3)0 (−5 to 6)−2 (−7 to 3)−2 (−7 to 3)−2 (−6 to 2)1 (−5 to 6)
       GReferentReferentReferentReferentReferentReferent
       H−2 (−5 to 2)−3 (−7 to 0)−2 (−6 to 2)−2 (−6 to 1)−2 (−6 to 1)0 (−4 to 4)
      StageP < .0001
       I3 (−1 to 6)
       IIReferent
       III−1 (−4 to 1)
       IV−12 (−15 to −10)
       Unknown−8 (−10 to −5)
      All values are difference (95% CI) in treatment interval length at the 50th percentile. SA, Sensitivity analyses; ADG, Aggregate Diagnosis Group; LHIN, Local Health Integration Network.
      SA.1 = removal of LHIN.
      SA.2 = removal of immigration.
      SA.3 = removal of rurality.
      § SA.4 = removal of immigration and rurality.
      SA.5 = removal of treatment group.
      SA.6 = addition of stage.
      # Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      Table E5Comparison of original model with SA
      Original modelSA.1
      SA.1 = removal of LHIN.
      SA.2
      SA.2 = removal of immigration.
      SA.3
      SA.3 = removal of rurality.
      SA.4
      SA.4 = removal of immigration and rurality.
      SA.5
      SA.5 = removal of treatment group.
      SA.6
      SA.6 = addition of stage.
      Adjusted intercept55 (45-65)61 (54-67)63 (54-72)64 (56-73)63 (55-72)68 (57-78)66 (57-75)
      Age group, yP = .03P = .09P = .05P = .01P = .03P = .0006P = .10
       18-49−6 (−14 to 2)−7 (−16 to 1)−6 (−13 to 2)−6 (−15 to 2)−6 (−14 to 3)−9 (−17 to −1)−4 (−12 to 4)
       50-592 (−2 to 6)1 (−3 to 5)2 (−2 to 6)2 (−2 to 6)2 (−3 to 6)3 (−2 to 8)2 (−2 to 6)
       60-69ReferentReferentReferentReferentReferentReferentReferent
       70-794 (0-7)3 (−1 to 7)4 (0-8)5 (1-9)5 (1-9)7 (2-11)4 (1-8)
       ≥806 (0-12)5 (−1 to 12)6 (0-13)7 (1-13)7 (1-13)7 (1-13)4 (−2 to 10)
      SexP = 1.0P = .44P = .93P = .81P = 1.0P = .42P = .70
       FemaleReferentReferentReferentReferentReferentReferentReferent
       Male0 (−4 to 4)−2 (−5 to 2)0 (−4 to 4)−1 (−4 to 3)0 (−4 to 3)0 (−4 to 3)−1 (−4 to 3)
      Sum of minor ADGsP = .39P = .05P = .35P = .32P = .40P = .05P = .32
       0-2ReferentReferentReferentReferentReferentReferentReferent
       3-42 (−2 to 6)4 (−1 to 8)2 (−2 to 7)2 (−2 to 7)2 (−3 to 6)2 (−3 to 6)2 (−3 to 6)
       5-63 (−1 to 8)5 (0-9)3 (−1 to 8)3 (−1 to 7)3 (−1 to 7)4 (−1 to 9)3 (−1 to 7)
       ≥74 (−1 to 9)7 (2-12)4 (−1 to 10)4 (−1 to 9)4 (−1 to 9)8 (2-15)5 (0-10)
      Sum of Major ADGsP = .003P = .01P = .002P = .002P = .005P = .03P = .003
       0ReferentReferentReferentReferentReferentReferentReferent
       14 (0-8)3 (−1 to 6)4 (0-8)3 (−1 to 7)3 (−1 to 7)3 (−1 to 7)3 (0-7)
       28 (3-13)8 (2-14)8 (3-13)7 (2-12)7 (2-13)8 (2-15)8 (3-13)
       ≥311 (4-17)9 (3-15)10 (4-17)11 (5-17)10 (4-17)8 (0-16)9 (3-14)
      Material deprivationP = .005P = .01P = .003P = .02P = .02P = .20P = .04
       1ReferentReferentReferentReferentReferentReferentReferent
       2−3 (−8 to 2)−2 (−7 to 3)−3 (−8 to 2)−2 (−8 to 3)−2 (−7 to 3)0 (−6 to 7)−3 (−7 to 2)
       32 (−4 to 7)2 (−3 to 7)2 (−3 to 6)1 (−4 to 6)2 (−3 to 6)2 (−4 to 7)−1 (−5 to 4)
       41 (−4 to 6)3 (−2 to 9)1 (−4 to 6)2 (−4 to 7)2 (−3 to 7)2 (−5 to 8)1 (−5 to 6)
       56 (0-11)5 (0-9)6 (1-10)5 (1-10)6 (1-10)6 (0-12)5 (0-9)
      RuralityP = .04P = .15P = .04P = .14P = .05
       UrbanReferentReferentReferentReferentReferent
       Rural6 (0-11)3 (−1 to 7)6 (0-12)5 (−2 to 13)5 (0-11)
      Recent immigrationP = .78P = .45P = .61P = .39P = .91
       NoReferentReferentReferentReferentReferent
       Yes1 (−6 to 8)2 (−4 to 8)2 (−6 to 10)4 (−5 to 12)0 (−6 to 7)
      HistologyP = .23P = .82P = .21P = .16P = .26P = .02P = .21
       AdenocarcinomaReferentReferentReferentReferentReferentReferentReferent
       Squamous cell carcinoma−4 (−9 to 1)−1 (−6 to 3)−4 (−9 to 0)−4 (9 to 0)−34 (−8 to 1)−8 (−13 to −2)−3 (−7 to 1)
       Other−2 (−8 to 5)−1 (8 to 5)−2 (−8 to 4)−2 (−8 to 5)−1 (−8 to 5)−5 (−12 to 2)−3 (−10 to 4)
      Tumor siteP = .10P = .08P = .21P = .05P = .10P = .008P = .08
       Cervical esophagus−10 (−23 to 4)−10 (−23 to 3)−10 (−24 to 5)−9 (−23 to 5)−11 (−24 to 3)−10 (−26 to 6)−5 (−17 to 7)
       Upper esophagus−3 (−15 to 18)−4 (−22 to 13)−3 (−16 to 10)−5 (−17 to 8)−4 (−17 to 8)−3 (−20 to 14)−5 (−18 to 8)
       Middle esophagus−1 (−9 to 6)−2 (−8 to 4)−1 (−8 to 6)−1 (−7 to 5)−1 (−8 to 6)−7 (−13 to 0)−3 (−9 to 3)
       Lower esophagus−4 (−8 to 0)−5 (−8 to −1)−4 (−7 to 0)−4 (−7 to −1)−4 (−7 to −1)−7 (−11 to −3)−4 (−7 to −1)
       Gastroesophageal junctionReferentReferentReferentReferentReferentReferentReferent
       Other4 (−6 to 13)2 (−9 to 12)4 (−6 to 14)4 (−6 to 14)4 (−6 to 14)4 (−7 to 15)4 (−7 to 14)
      LHINP < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       01−9 (−17 to 1)−10 (−18 to 0)−10 (−18 to −1)−9 (−17 to −1)−5 (−14 to 3)−9 (−17 to −1)
       02−2 (−11 to 6)−3 (−11 to 5)−2 (−10 to 6)−2 (−9 to 5)5 (−4 to 14)−2 (−9 to 6)
       03−1 (−8 to 6)−1 (9 to 7)−1 (−9 to 7)−1 (−8 to 6)6 (−2 to 14)1 (−5 to 8)
       04−12 (−18 to −7)−12 (−19 to −6)−13 (−19 to −7)−12 (−18 to −6)−7 (−13 to 0)−12 (−17 to −6)
       05−1 (−10 to 9)−0 (−10 to 10)−1 (−11 to 9)0 (−9 to 9)2 (−10 to 13)1 (−8 to 11)
       067 (−1 to 16)7 (−2 to 16)7 (−2 to 15)7 (−2 to 16)14 (2-26)5 (−4 to 13)
       07−4 (−11 to 4)−4 (−11 to 4)−4 (−12 to 3)−3 (−13 to 6)2 (−8 to 12)−5 (−13 to 3)
       08−3 (−10 to 4)−2 (−10 to 6)−4 (−13 to 4)−2 (−10 to 6)−1 (−11 to 9)−3 (−11 to 4)
       09ReferentReferentReferentReferentReferentReferent
       10−2 (−10 to 5)−3 (−10 to 5)−2 (−9 to 5)−1 (−9 to 7)4 (−5 to 13)−1 (−7 to 5)
       11−1 (−9 to 7)−1 (−9 to 6)−2 (−9 to 6)−1 (−8 to 7)8 (−1 to 17)−0 (−7 to 6)
       12−1 (−12 to 8)−2 (−13 to 9)−2 (−11 to 9)−1 (−12 to 10)−8 (−21 to 6)−4 (−14 to 6)
       13−12 (−18 to −6)−12 (−19 to −5)−12 (−18 to −5)−11 (−18 to −4)−7 (−15 to 1)−11 (−18 to −5)
       14−9 (−19 to 1)−9 (−21 to 3)−6 (−18 to 5)−56 (−16 to 4)3 (−7 to 13)−8 (−17 to 1)
      Treatment group
      Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      P < .0001P < .0001P < .0001P < .0001P < .0001P < .0001
       A−16 (−22 to −10)−15 (−21 to −8)−15 (−21 to −10)−16 (−22 to −9)−15 (−21 to −9)−11 (−18 to −5)
       B21 (14-27)19 (13-26)21 (15-27)20 (13-27)20 (13-27)27 (21-33)
       C6 (0-13)5 (0-11)7 (1-12)6 (0-12)7 (0-13)11 (5-17)
       D37 (29-44)38 (30-46)37 (29-45)38 (30-46)38 (30-47)34 (27-42)
       E8 (4-12)7 (3-12)8 (4-12)8 (4-12)8 (4-12)11 (6-15)
       F0 (−9 to 9)−3 (−12 to 6)0 (−8 to 9)−0 (−9 to 9)0 (−9 to 9)−2 (−8 to 5)
       GReferentReferentReferentReferentReferentReferent
       H−4 (−10 to 2)−4 (−10 to 2)−3 (−9 to 2)−3 (−9 to 3)−4 (−11 to 3)−4 (−10 to 3)
      StageP < .0001
       I13 (4-22)
       IIReferent
       III−4 (−8 to 1)
       IV−16 (−21 to −11)
       Unknown−1 (−5 to 3)
      All values are difference (95% CI) in treatment interval length at the 90th percentile. SA, Sensitivity analyses; ADG, Aggregate Diagnosis Group; LHIN, Local Health Integration Network.
      SA.1 = removal of LHIN.
      SA.2 = removal of immigration.
      SA.3 = removal of rurality.
      § SA.4 = removal of immigration and rurality.
      SA.5 = removal of treatment group.
      SA.6 = addition of stage.
      # Treatment group: A = endoscopy with or without subsequent treatment; B = chemotherapy only; C = radiotherapy only; D = surgery with or without subsequent treatment; E = chemotherapy and radiotherapy; F = chemotherapy or radiotherapy then surgery; G = chemotherapy and radiotherapy then surgery; and H = other.
      Table E6LHIN of residence at diagnosis
      1234567891011121314TotalP value
      Total3455233238322463753744966743075172813531295775
      Age, y.04
       18-49201921401828322426112114166296
       50-597388651514764728214161946174321105
       60-6911518610427278138120142218104180100114521923
       70-79881577824570100941551848914363106241596
       ≥80497355124334556931054279434315855
      Sex.02
       Female76107741786292101135147551025870361293
       Male269416249654184283273361527252415223283934482
      Minor ADGs<.0001
       0183422482018172444192417258338
       1-253988216728505975109671016280231054
       3-49515181215579786105182801286996391481
       5-697120791885011382139151821377977271421
       ≥782120592149197130153188591275475321481
      Major ADGs.21
       01252041362967914712915821911220398140512097
       1101157100253741211101582259715495111431799
       26991541495467729812654805365161048
       ≥3507133134394063821044480353719831
      Material deprivation<.0001
       145999117825991118483371483223201075
       26611569161339355129132731096146131155
       364907314757905710713059957267221130
       461103471627462559518257806195421176
       51051144217557309479147768252115301198
      Immigration and rurality removed because of small cell numbers. ADG, Aggregate Diagnosis Group.

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