Second malignant neoplasms following childhood cancer: a study of a recent cohort (1987-2004) from the childhood cancer registry of the Rhône-Alpes region (ARCERRA) in France.

Studies of second malignant neoplasms (SMNs) in childhood are generally conducted in old cohorts. The aim of this study was to determine the actual incidence of all SMNs in a recent cohort. The authors studied a cohort of 2907 children included in the population-based Childhood Cancer Registry of the Rhône-Alpes Region for a first cancer diagnosed between 1987 and 2004. Total follow-up was 22,722 person-years, with a median follow-up of 9.8 years (range, 00.0-22.8 years). Fifty-four SMNs were reported in 52 patients. Overall median latency was 5.9 years. Cumulative incidence rates were 2.2% at 10 years and 3.9% at 15, with an overall standardized incidence ratio (SIR) of 13.9 (95% confidence interval [CI], 10.4-18.3) and absolute excess risk of 2.2. The SMNs were 12 thyroid carcinomas (SIR 57.1); 9 bone tumors (SIR 32.0); 8 leukemias (SIR 11.9); 5 lymphomas, all related to Epstein-Barr virus following allograft, (SIR 6.7); 5 CNS tumors (SIR 10.5); 4 soft tissue sarcomas (SIR 17.4); 4 carcinomas (no breast cancer); and 7 other cancers. Twelve SMNs appeared after total body irradiation, 16 after focal radiotherapy, and 8 leukemias after chemotherapy. The risk of secondary cancer was highest after retinoblastomas (SIR 41.8), Hodgkin lymphomas (SIR 20.8), leukemias (SIR 18.4), soft tissue sarcomas, CNS tumors, and bone tumors. These recent cohort findings show, on one hand, a high incidence of SMNs but do not capture breast cancers because of the relatively short follow-up and, on the other hand, a different distribution of first and second cancers.