Case-control analysis of cumulative absolute risk of colorectal cancer in survivors after abdominopelvic radiotherapy for childhood cancer

Childhood cancer survivors are at risk of developing subsequent colorectal cancer (CRC), but the absolute risks by treatment modality are uncertain. Case-control analysis in a European cohort of childhood cancer survivors found that abdominopelvic radiotherapy (ART) for childhood cancer was associated with elevated risk of CRC (OR 3.1; 95% CI 1.4-6.6). After ART for childhood cancer, the cumulative absolute risk (CAR) of CRC at age forty years was 0.27% among males and 0.29% among females, the CAR at age fifty years was 1.08% among males and 1.03% among females, and the CAR at age sixty years was 3.7% among males and 3.0% among females. The authors conclude that by age forty years survivors of childhood cancer treated with ART already have a similar risk of CRC as the general population by age fifty years (the age of beginning of CRC screening in many countries).