A 20-year prospective study of Wilms tumor and other kidney tumors: a report from Hong Kong pediatric hematology and oncology study group.

BACKGROUND Renal tumors are one of the most common tumors in children. We aim at evaluating the characteristics and the outcome of Wilms tumor and other malignant kidney tumors in Hong Kong. PROCEDURE Between January 1990 to December 2010, 68 patients under the age of 18 with malignant renal tumors were diagnosed and received treatment in Hong Kong. Clinical records were updated regularly. Prognostic factors and survival rate were evaluated. RESULTS Fifty-four patients were diagnosed with Wilms tumor. The annual incidence was estimated to be 2.29 per million. The mean age was 38 months. Median follow-up was 9.2 years. The event-free survival and overall survival rate at 10 years were 85.2% and 92.6%, respectively. A pair of siblings with familial extrarenal Wilms tumor was included. Pulmonary metastasis did exhibit a significant difference in survival rate. Eight cases of clear cell sarcoma of the kidneys were reported and the survival rate was 100%. CONCLUSIONS The clinical characteristics and outcome of the patients diagnosed Wilms tumor were comparable with other developed countries. Relatively high proportion and excellent outcome were found in clear cell sarcoma of the kidneys.