Subsequent Renal Cancer among Childhood Cancer Survivors: Analysis of Surveillance, Epidemiology, and End Results.

Renal cancer, although still rare among individuals under 45 years of age, is on the rise in the general population. The risk and timing of subsequent renal cancer in survivors of childhood cancer is not well established. Using the SEER registry, we reported the incidence of subsequent malignant renal neoplasms after treatment for primary malignancy diagnosed under 20 years of age. We evaluated clinical characteristics, standardized incidence ratio (SIR), and Kaplan-Meier survival estimates. Fifty-three survivors developed subsequent renal cancer (54 total cases). Of these, 54.7% were female, 88.7% were white, and 13.2% were Hispanic. Mean ages at primary malignancy and subsequent renal cancer were 10.1 and 31.1 years, respectively. Forty-seven cases were second cancers, 6 were third, and 1 was fourth. For survivors of childhood cancer, the overall SIR for renal cancer was 4.52 (95% CI: 3.39-5.89). The 5-year overall survival rate after development of subsequent renal cancer was 73% (95% CI: 58%-83%). Renal cancer occurs 4.5 times more frequently in childhood cancer survivors than in the general population, necessitating long-term care considerations.