Estimates of the future burden of cancer attributable to infections in Canada

More than 7000 incident cancers diagnosed in Canada in 2015 were attributable to infections. The future infection-associated cancer burden can be lowered by reducing the prevalence of major cancer-causing infections; hepatitis B virus (HBV), hepatitis C virus (HCV), Helicobacter pylori (H. pylori) and human papillomavirus (HPV). We modeled the future impact of (1) 10%, 25%, and 50% relative reductions in the prevalence of HBV, HCV and H. pylori and (2) different school-based HPV vaccination coverage levels (lower, current, higher) on Canadian cancer incidence by the year 2042. We modeled counterfactual reductions in HBV, HCV and H. pylori prevalence in 2018, assuming a latency period of 15-years, to estimate the impact on cancer incidence starting in 2033. The number of HPV-attributable cancers among vaccinated cohorts was a function of pre-2018 vaccine coverage levels and the 2018 counterfactuals. A 50% counterfactual reduction in the prevalence of HBV, HCV and H. pylori could prevent an estimated 10,585 cancers from 2018 to 2042; a 25% reduction could prevent 5293 cancers and a 10% reduction could prevent 2117 cancers. Assuming continuity of current estimated country-wide HPV vaccine coverage, 3977 anogenital and 1073 head and neck cancers could be prevented from 2018 to 2042, whereas vaccine coverage of 80% in girls and boys could prevent an additional 311 cancers. Almost 16,000 cancers could be prevented in Canada from 2018 to 2042 with a 50% relative reduction in HBV, HCV and H. pylori prevalence and 80% HPV vaccine coverage of girls and boys.