Stage of diagnosis and survival for prostate cancer among immigrant men in Ontario, Canada

Introduction — We previously identified specific immigrant groups (West African and Caribbean) with increased incidence of prostate cancer in Ontario, Canada. In this population-level retrospective cohort study, we used administrative databases to compare stage of diagnosis, 5-year overall survival and prostate cancer-specific survival for immigrants versus long-term residents of Ontario.

Methods — We linked several provincial-level databases available at ICES, an independent, non-profit research institute. We included all male Ontario residents 20–105 years of age who had an incident prostate cancer diagnosis date between March 31, 2008 and March 31, 2017, stratified into immigrants vs. long-term residents. We used multivariable logistic regression to determine the odds of early (stage I-II) vs. late (III-IV) stage of diagnosis, adjusting for age, co-morbidities, neighbourhood income and continuity of care. We produced Kaplan-Meier curves for 5-year overall survival and for 5-year prostate cancer-specific survival.

Results — Compared to long-term residents, men from West Africa (adjusted odds ratio 1.66 [95% CI 1.16–2.38], East Africa (AOR 1.54 [95% CI 1.02–2.33]) and the Caribbean (AOR 1.22 [95% CI 1.01–1.47]) had a diagnostic stage advantage, and men from South Asia were most likely to be diagnosed at a late stage. In both unadjusted and adjusted analyses, overall and prostate cancer-specific survival were higher for immigrants than long-term residents. The highest five-year overall survival was seen for men from Sub-Saharan Africa and the Caribbean, and the lowest was seen for South Asian men, where 11.7% died within five years of diagnosis.

Conclusion — Immigrant men in Ontario with prostate cancer are more likely to be diagnosed at an early stage and to survive for 5 years than long-term residents. Among immigrant men, men from the Caribbean and Sub-Saharan Africa have the greatest stage and survival advantage and South Asian men the least. Differences in awareness, diagnostic suspicion, genetic predisposition, and social factors may play a role in these findings.