Outcomes of Children With Favorable Histology Wilms Tumor and Peritoneal Implants Treated in National Wilms Tumor Studies-4 and -5

Purpose: There are no published reports on the optimal management and survival rates of children with Wilms tumor (WT) and peritoneal implants (PIs). Methods and Materials: Among favorable histology WT patients enrolled in the National Wilms Tumor Study (NWTS)-4 and NWTS-5, 57 children had PIs at the time of nephrectomy. The median age was 3 years 5 months (range, 3 months to 14 years). The majority of children (42 of 57 [74%)] had Stage III tumors; 15 had Stage IV disease. All patients received multimodality therapy. Of 56 children who underwent primary surgery, 48 (84%) had gross total resection of all tumors. All patients received 3-drug chemotherapy with vincristine, dactinomycin, and doxorubicin. Whole-abdomen radiotherapy (RT) was used in 47 patients (82%), and in 50 patients (88%) the RT dose was 10.5 Gy. Results: After a median follow-up of 7.5 years, the overall abdominal and systemic tumor control rates were 97% and 93%, respectively. A comparative analysis between children with PIs and those without PIs showed no significant differences in the clinical characteristics between the two groups. The 5-year event-free survival rates with and without PIs were 90% (95% confidence interval, 78-96%) and 83% (95% confidence interval, 81-85%) respectively (p = 0.20). Conclusions: Multimodality therapy with surgery, whole-abdomen RT, and three-drug chemotherapy delivered according to the NWTS-4 and -5 protocols resulted in excellent abdominal and systemic tumor control rates. All children should be monitored in long-term surveillance programs for the early detection and management of therapy-related toxicities.