Breast cancer (BC) risk among 3-year survivors of a first pediatric cancer (FC)

Abstract

8531 Background: Long-term survival of patients treated for a pediatric cancer is dramatically improved. Nevertheless, in this context, the risk for occurrence of subsequent cancer, and particularly of breast cancer knowing that child's breast is very radiosensitive, is a significant data for the monitoring of the survivors. Methods: Data on chemotherapy and radiotherapy were collected for each of the 1,817 3-year female, survivors from a FC diagnosed before age 17, treated in eight French and English centers. Individual estimation of radiation dose to each breast was performed for the 1,261 patients treated by external radiotherapy, delivered in 24 fractions (mean); mean dose to breasts was 5.06 Gy (range 0.0–78.6). Results: Within a 16-year mean follow-up, sixteen BC occurred leading to a cumulative probability of 2.9% [95%CI: 0.98–4.9] 30 years after the FC and of 5.5% [95%CI: 2.1 to 8.9 %] at age 40. The annual excess incidence rose as age increased whereas the Standardized Incidence Ratio (SIR) decre...