Population-based study of renal cell carcinoma in children in Germany, 1980-2005: more frequently localized tumors and underlying disorders compared with adult counterparts.

BACKGROUND: Childhood renal cell carcinomas (RCCs) differ histologically and biologically from their adult counterparts. The characteristics of RCC-affected children and their tumors, the influence of treatment, and outcome have so far not been studied in a nonselected, population-based cohort. METHODS: A retrospective analysis was undertaken of RCC patients less than 16 years old reported to the German Childhood Cancer Registry and to the Kiel Paediatric Tumor Registry from 1980 to 2005. RESULTS: Forty-nine RCC in children (24 boys, 25 girls) with a median age of 10.6 years were identified. In about every third child possibly RCC-related underlying disorders (tuberous sclerosis, neuroblastoma, teratoma with chemotherapy, Saethre-Chotzen syndrome, chronic renal failure) or related diseases in their family were found. The pathologic subtypes were papillary in 16 (33%), translocation type in 11 (22%), unclassified in 8 (16%), and rarely clear-cell (n = 3) or others. Thirty-four (69%) patients had localized RCC, 8 (16%) patients regional lymph node metastases, and 4 (8%) patients distant metastases. Event-free survival and overall survival rates at 5 years were 96% for localized RCC, 69% and 75% for regional lymph node-positive, 25% and 33% for distant metastatic RCC, respectively. Two of 4 patients with distant metastases received immunotherapy combined with chemotherapy and surgery, both are alive, 1 of them disease-free for 6.9 years. CONCLUSIONS: Pediatric RCCs are predominantly localized diseases. Children with RCC frequently suffer underlying disorders. Survival rates in localized and regional lymph node-positive cases are favorable. Because of the rarity of RCC in childhood, an international study is necessary.