CMAJ
Cancer risk doubles for younger cancer survivors
Clinical takeaway: Cancer survivors diagnosed at ages 15 to 39 require long-term, risk-based surveillance. Earlier screening for breast and colorectal cancer may be warranted in high-risk groups.
Cancer survival in adolescents and young adults is high, but long-term risks are increasingly recognized. Cancer incidence in adolescents and young adults has been rising, creating an increasing population of survivors at risk for long-term complications. This study examined the risk of new primary cancers among survivors over extended follow-up.
In a population-based cohort of 24,459 patients diagnosed between ages 15 and 39, 6% developed a second primary cancer over a median of 7.4 years of follow-up. The overall risk was about double that of the general population.
Among five-year survivors, the 30-year cumulative incidence of a second cancer was 17.7%, or roughly 1 in 6 patients. Certain groups are at particularly high risk. Survivors of Hodgkin lymphoma, breast cancer, colon cancer, and head and neck cancers had the highest long-term incidence of second cancers, with rates approaching 20% to 30% over 30 years.
Breast, digestive, hematologic, and lung cancers accounted for most second cancers, together representing nearly 60% of cases.
Treatment exposures likely drive much of this risk. Higher rates were seen in patients who received radiotherapy or combined modality treatment, consistent with known late effects.
Second cancers also occur earlier than in the general population. Median age at diagnosis for breast, colorectal, and lung cancers in survivors was 48 to 58 years, well below typical population averages.
“When combined with the relatively high survival rates in this age range, at approximately 86%, there is a growing population of young cancer survivors that will be adversely affected by their cancer diagnosis and its treatment even decades later,” the authors note.
Source: Alam AU. CMAJ. 2026 Apr 13. Subsequent primary neoplasm risk among survivors of cancer in adolescence and young adulthood