Childhood cancer survivors who are obese and less physically active face a significantly higher risk of developing subsequent cancers later in life, according to new research from Lenat Joffe, Northwell, New York, USA, and colleagues.
The large-scale cohort study analysed data from 22716 five-year survivors of childhood cancer, originally diagnosed before age 21 between 1970 and 1999. Participants were enrolled in the long-running Childhood Cancer Survivor Study (CCSS) across pediatric tertiary hospitals in the US and Canada, with follow-up continuing through 2019.
Researchers evaluated the relationship between time-varying body mass index (BMI), physical activity levels, and the development of secondary cancers. Over the study period, 2,554 subsequent neoplasms were reported among 2,156 survivors, with the median age at secondary cancer diagnosis being 37.
Findings showed that survivors with obesity faced a higher incidence of solid organ, central nervous system (CNS), and skin cancers compared to those with a healthy BMI. Conversely, maintaining regular physical activity proved to be protective. Survivors who engaged in 15–21 hours of activity per week had a markedly lower 30-year cumulative incidence of new cancers (10.9%) compared to those reporting no activity (18.6%).
The study noted particularly strong links between lifestyle factors and the risk of meningiomas and thyroid cancers, though no significant associations were found with breast, colorectal, or hematologic cancers.
Researchers concluded that healthy weight management and regular physical activity may help mitigate long-term cancer risk in this vulnerable population. They recommend incorporating lifestyle interventions into survivorship care and cancer prevention strategies.
Reference
Joffe L et al. Body mass index, physical activity, and subsequent neoplasm risk among childhood cancer survivors. JAMA Oncol. 2025;11;(8):835-45.
