Long-term Risks of Subsequent Primary Neoplasms Among Survivors of Childhood Cancer

Context Survivors of childhood cancer are at excess risk of developing subsequent primary neoplasms but the long-term risks are uncertain. Objectives To investigate long-term risks of subsequent primary neoplasms in survivors of childhood cancer, to identify the types that contribute most to long-term excess risk, and to identify subgroups of survivors at substantially increased risk of particular subsequent primary neoplasms that may require specific interventions. Design, Setting, and Participants British Childhood Cancer Survivor Study-a population-based cohort of 17 981 5-year survivors of childhood cancer diagnosed with cancer at younger than 15 years between 1940 and 1991 in Great Britain, followed up through December 2006. Main Outcome Measures Standardized incidence ratios (SIRs), absolute excess risks (AERs), and cumulative incidence of subsequent primary neoplasms. Results After a median follow-up time of 24.3 years (mean=25.6 years), 1354 subsequent primary neoplasms were ascertained; the most frequently observed being central nervous system (n=344), nonmelanoma skin cancer (n=278), digestive (n=105), genitourinary (n=100), breast (n=97), and bone (n=94). The overall SIR was 4 times more than expected (SIR, 3.9; 95% confidence interval [CI], 3.6-4.2; AER, 16.8 per 10 000 person-years). The AER at older than 40 years was highest for digestive and genitourinary subsequent primary neoplasms (AER, 5.9 [95% CI, 2.5-9.3]; and AER, 6.0 [95% CI, 2.3-9.6] per 10 000 person-years, respectively); 36% of the total AER was attributable to these 2 subsequent primary neoplasm sites. The cumulative incidence of colorectal cancer for survivors treated with direct abdominopelvic irradiation was 1.4% (95% CI, 0.7%-2.6%) by age 50 years, comparable with the 1.2% risk in individuals with at least 2 first-degree relatives affected by colorectal cancer. Conclusion Among a cohort of British childhood cancer survivors, the greatest excess risk associated with subsequent primary neoplasms at older than 40 years was for digestive and genitourinary neoplasms. JAMA. 2011;305(22):2311-2319 www.jama.com