Incidence, mortality, and cumulative risk of cancer in adolescents and young adults in Switzerland

Cancers in adolescents and young adults (AYAs, aged 15-39 years) have distinct features and distribution of cancer types. This study investigated incidence, mortality, and cumulative risk of AYA cancers in Switzerland. Data on adolescent cancers (15-19 years; Swiss Childhood Cancer Registry) and young adult cancers (20-39 years; National Agency for Cancer Registration) were combined. We calculated age-standardized incidence and mortality rates, and accounted for incomplete regional coverage of cancer registration. We used joinpoint regression to investigate cancer incidence and mortality trends and estimate average annual percent changes. We included 44,048 cancers recorded between 1980 and 2019 and, after adjusting for incomplete coverage, we estimated a total of 69,901 cancers. Cancer incidence increased from 56.6 [95% confidence interval: 55.3, 58.0] per 100,000 person-years in 1980-1989 to 72.2 [71.1, 73.3] in 2010-2019, with a steeper increase for females. The most common cancers were carcinomas, mainly of the breast (9,629 cancers estimated), gastrointestinal tract (5,033) and thyroid (4,785), gonadal and related tumors (11,303), melanomas (9,695), and lymphomas (8,208). There were 9,865 AYA cancer deaths recorded over the study period. The age-standardized mortality rate declined from 13.3 [12.8, 13.7] per 100,000 person-years in 1980-1989 to 6.2 [5.9, 6.5] in 2010-2019, showing similar decreases in both sexes. This first comprehensive, nationwide study of AYA cancers in Switzerland showed increasing incidence and declining mortality, potentially due to changes in lifestyle or improved cancer registration and screening practices. Our results emphasize the need for ongoing surveillance and preventive strategies with a focus on AYAs.