Clinical features of Wilms' tumor and treatment results

We retrospectively reviewed 34 children treated for Wilms' tumors at Chang-Gung Memorial Hospital from September 1979 to April 1992. The clinical data were analyzed. Patients were treated with standard multimodal therapy; three patients received preoperative chemotherapy. The survival and relapse-free survival curves were calculated for the overall group and compared with prognostic variables. Patients included 20 boys and 14 girls; the median age at diagnosis was 2 years 1 month. Congenital anomalies, hypertension and gross hematuria were found in 11.8%, 17.9% and 17.9%, respectively. The tumors were on the right side in 19 patients, on the left side in 13, and bilateral in two. Tumor weights ranged from 95 g (following preoperative chemotherapy) to 3500 g. The tumor was histologically favorable in 29 cases (85.3%), anaplastic in two and clear cell sarcoma in three. The clinical stages of these patients were: stage 1, 10; stage II, five; stage III, 15, stage IV, two; and stage V, two. The median follow-up duration was 26 months (range, eight weeks to 12 years 10 months). Eight patients had a poor outcome and four patients died of disease. The probability of survival was 83.6% and the relapse-free survival was 69.4% at five years. Tumor histology and clinical stage were associated with statistically significant differences in outcome. The complications and patterns of relapse are discussed. The annual incidence rate of Wilms' tumor in Taiwan is estimated to be 2.7 per million children under the age of 15 years.