New Insights into the Epidemiology of Prostate Cancer in Ontario

The epidemiology of prostate cancer (PC) continues to change. We evaluated the changes in incidence, in average age at diagnosis, and in survival from 1992 to 2015 in Ontario. We compared the cumulative incidence of PC-specific and non PC-specific mortality using two algorithms for cause of death: Method 1 assigned deaths from "other cancers" to non PC-specific causes, and Method 2 assigned these cases to PC-specific mortality. There were 188,714 cases diagnosed with PC between 1992 and 2015 in Ontario. The average age at diagnosis declined from 1992 to 2008 by 0.26 year (3.1 months) annually (p < 0.001) and increased by 0.15 year (1.8 months) thereafter (p > 0.05). Between 2010 and 2015, the proportion of patients diagnosed at stage IV increased, and the proportion diagnosed at stage I decreased (p-values for trends <0.001). Overall survival significantly improved over the years. The cumulative incidence of PC-specific mortality at 5 and 10 years was 6.8 and 9.8% using Method 1, and 10.2 and 16.8% using Method 2. We observed trends toward older age and more advanced stage at PC diagnosis in Ontario. Further studies are needed to validate algorithms for estimating PC-specific mortality from administrative databases.