50-year Trends in Cancer Incidence and Mortality among Adolescents and Young Adults in British Columbia, Canada

Introduction: Adolescents and young adults (AYAs) with cancer constitute a distinct population with unique biological and survivorship challenges. Long-term, population-based analyses of incidence and mortality trends in AYAs remain limited. Methods: We conducted a retrospective, longitudinal population-based cohort study using data from the Childhood, Adolescent, and Young Adult Cancer Survivor program in British Columbia, Canada, from 1971 to 2020. We analyzed age-standardized incidence rates (ASIR) for the 16 cancer types with the highest incidence and age-standardized mortality rates (ASMR) for the 8 cancer types with the highest mortality, overall and by sex. Trends were evaluated using annual percentage change (APC) and average APC from joinpoint regression analyses. Results: The cohort included 43,588 patients with a first cancer diagnosis and 6825 deaths. From 1971 to 2020, cancer incidence rose overall (AAPC 0.1; 95% confidence interval [CI]: −1.0, 1.3), with a brief decline in the mid-1990s. Significant increases in ASIR were observed for thyroid (APC 1983–2020 : 3.0, 95% CI: 2.4, 3.6) and gastrointestinal cancers (APC 1988–2020 : 1.9, 95% CI: 1.3, 2.6). Female AYAs showed rising trends in Hodgkin and non-Hodgkin lymphoma, while testicular cancer incidence increased among males. Male AYAs had higher all-cause mortality (51.6%). Cancer mortality declined beginning in the early 1990s; however, gastrointestinal cancer mortality increased in males (APC 1990–2020 : 1.7, 95% CI: 0.3, 3.1). Conclusions: Cancer incidence among AYAs has risen over five decades, particularly for thyroid and gastrointestinal cancers, with concerning increases in gastrointestinal cancer mortality among males. These findings emphasize the need for targeted prevention, screening, and intervention strategies.