ArticleBMJ open2022
Explaining regional variations in colon cancer survival in Ontario, Canada: a population-based retrospective cohort study.
Article in BMJ open, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
4 citing papers in PubMed.
- Rural-urban disparities in cardiovascular and other competing risk of death among cancer patients.Journal of advanced research · 2026Article
- Concussions and risk of a subsequent traffic crash: retrospective cohort analysis in Ontario, Canada.BMJ open · 2025Article
- Temporal changes in regional variations in cancer survival rates in Osaka, Japan (1997-2015).Scientific reports · 2025Article
- Regional and sociodemographic variation of incident first-episode psychosis in Ontario, Canada.International journal of population data science · 2025Article
Corrections and comments
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Authors and funding
9 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectivesRegional variation in cancer survival is an important health system performance measurement. We evaluated if regional variation in colon cancer survival may be driven by differences in the patient population, their health and healthcare utilisation, and/or cancer care delivery.
designPopulation-based retrospective cohort study using routinely collected linked health administrative data.
settingOntario, Canada.
participantsPatients with colon cancer diagnosed between 1 January 2009 and 31 December 2012. OUTCOME: Cancer-specific survival was compared across the province's 14 health regions. Using accelerated failure time models, we assessed whether regional survival variations were mediated through differences in case mix, including age, sex, comorbidities, stage at diagnosis and colon subsite, potential marginalisation and/or prediagnosis healthcare.
resultsThe study population included 16 895 patients with colon cancer. There was statistically significant regional variation in cancer-specific survival. Three regions had cancer-specific survival that was between 30% (95% CI 1.03 to 1.65) and 39% (95% CI 1.13 to 1.71) longer and one region had cancer-specific survival that was 26% shorter (95% CI 0.58 to 0.93) than the reference region. For three of these regions, case mix explained between 26% and 56% of the survival variation. Further adjustment for rurality explained 22% of the remaining survival variation in one region. Adjustment for continuity of primary care and the diagnostic interval length explained 10% and 11% of the remaining survival variation in two other regions. Socioeconomic marginalisation, recent immigration and colonoscopy history did not explain colon cancer survival variation.
conclusionsCase mix accounted for much of the regional variation in colon cancer survival, indicating that efforts to monitor the quality of cancer care through survival metrics should consider case mix when reporting regional survival differences. Future work should repeat this approach in other settings and other cancer sites considering a broad range of potential mediators.
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