Risk of second malignancies in long-term survivors of childhood cancer

IntroductionChildhood cancer survivors are known to be at increased risk for second malignancies.Patients and methodsThe risk of second malignancies was assessed in 1368 5-year survivors of childhood cancer treated in the Emma Children’s Hospital AMC in Amsterdam. The median follow-up time was 16.8 years.ResultsSixty two malignancies were observed against 5.4 expected, yielding a standardised incidence ratio (SIR) of 11.2 (95% confidence interval: 8.53–14.4; absolute excess risk: 3.2 per 1000 person-years). New observations were the strongly increased risks of meningiomas (SIR = 40) and basal cell carcinomas (SIR = 9). Patients whose treatment involved radiotherapy had a 2-fold increased second cancer risk compared to patients with chemotherapy alone.DiscussionThe relative risk of second malignancies does not decrease till at least 30 years of follow-up. With aging of the survivor cohort this results in a strong increase of the AER, due to the rising background risk of cancer with age.