Dose-volume analysis of radiation nephropathy in children: preliminary report of the risk consortium.

Purpose To characterize kidney function in children and adolescents who had undergone radiation treatment that included parts of the kidney. Methods and Materials Patients receiving radiotherapy during childhood or adolescence were prospectively registered in Germany's Registry for the Evaluation of Side Effects after Radiation in Childhood and Adolescence (RiSK). Detailed information was recorded regarding radiation doses at the organs at risk since 2001 all over Germany. Toxicity evaluation was performed according to standardized Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. Results Up to May 2009, 1086 patients from 62 centers were recruited, including 126 patients (median age, 10.2 years) who underwent radiotherapy to parts of the kidneys. Maximal late toxicity (median follow-up 28.5 months in 74 patients) was characterized as Grade 0 ( n = 65), 1 ( n = 7) or 2 ( n = 2). All patients with late effects had received potentially nephrotoxic chemotherapy. A statistically significant difference between patients with and without Grade 1 toxicity, revealing higher exposed kidney volumes in patients with toxicity, was seen for the kidney volume exposed to 20 Gy (V20; p = 0.031) and 30 Gy (V30; p = 0.003). Conclusions Preliminary data indicate that radiation-induced kidney function impairment is rare in current pediatric multimodal treatment approaches. In the future, RiSK will be able to provide further detailed data regarding dose–volume effect relationships of radiation-associated side effects in pediatric oncology patients.