Renal carcinoma following therapy for cancer in childhood: A report from the Childhood Cancer Survivor Study.

Abstract

9528 Background: Limited data exists describing the incidence of and risk factors for subsequent renal carcinoma among long-term survivors of childhood cancer. Methods: The study included 14,351 five-year survivors of childhood cancer diagnosed between 1970 and 1986 who participated in the Childhood Cancer Survivor Study. Chemotherapy and radiotherapy exposures were abstracted from medical records; total dose of radiation to the renal beds was estimated by a radiation physicist. Standardized incidence ratios (SIRs) were calculated using age-, sex-, and calendar-specific incidence data from the Surveillance, Epidemiology and End Results (SEER) program. Cumulative incidence was calculated treating death as a competing risk. Poisson regression analyses were used to assess associations between diagnosis and treatment characteristics and the risk of subsequent renal carcinoma while adjusting for changes in risk due to age. Results: Twenty-six survivors were diagnosed with a renal carcinoma at a median follow-up of 19.3 years (range: 1 month to 34.3 years) from study entry at 5 years post diagnosis. Eight patients received ≥5Gy radiotherapy to a renal bed, 16 received chemotherapy, seven of whom seven received both radiotherapy ≥5Gy and chemotherapy. Cumulative incidence of renal carcinoma at 20 years was 0.16% (95% CI 0.12-0.20). The SIR was 8.1 (95% CI 5.3-11.8) comparing survivors to the general population. Highest risk for renal carcinoma was observed among survivors of neuroblastoma (SIR 87.1, 95% CI 38.4-175.2), non-Hodgkin lymphoma (SIR 9.3, 95% CI 1.9-27.4), and bone tumors (SIR 7.0, 95% CI 1.4-20.4). In multivariable analyses, the risk of subsequent renal carcinoma was elevated among survivors exposed to platinum-based chemotherapy (Rate Ratio 3.1, 95% CI 0.9-10.6) or renal bed radiotherapy ≥5Gy (RR 3.6, 95% CI 1.5-8.4). Conclusions: While cumulative incidence is low, survivors of childhood cancer are at an eight-fold increased risk for subsequent renal carcinoma compared to the general population. In addition to a primary diagnosis of neuroblastoma, radiotherapy directed to the renal bed increased the risk for renal carcinoma.