Is cancer increasing in young adults in Spain? Incidence trends from the Spanish Network of Cancer Registries (REDECAN)

This collaborative study within the Spanish Network of Cancer Registries (REDECAN) aimed to examine cancer incidence trends in young adults in Spain. A total of 153,599 new cancer cases (58% in women) were diagnosed during the study period. Trends were heterogeneous, with more increases observed in women. Incidence rose for kidney (APC=2.5%), thyroid (4.0%), and Hodgkin lymphoma (1.1%) in men and for pancreas (2.0%), Hodgkin (2.1%) and non-Hodgkin (1.7%) lymphoma in women. Several digestive system (stomach, colon, rectum), breast and cervical cancers increased significantly among the youngest adults (<40 years old). In contrast, incidence declined for larynx, lung, urinary bladder, and liver cancers in both sexes (APCs ranging between -3.1% to -8.7%), and for lip, oral cavity, and pharynx cancers in men. In young adults, incidence of smoking-associated cancers has decreased substantially, whereas some obesity-associated cancers have increased among adults 20-39 years old. These findings underscore the need for stronger cancer prevention measures and a better understanding of the rising incidence of some cancers in young adults.