Radiotherapy omitted in the treatment of selected children under 3 years of age with stage III favorable histology Wilms tumor.

Abstract

Current treatment of stage III favorable histology (FH) Wilms tumor is surgery, radiotherapy to residual disease, and "triple" chemotherapy (vincristine, dactinomycin, and doxorubicin) for 12 months. This study tests the hypothesis that some stage III patients, especially very young children with minimal residual abdominal disease, might be successfully treated without radiotherapy, thereby avoiding the adverse late effects associated with radiotherapy. From 1984, radiotherapy was omitted from the treatment of 8 carefully selected children who were younger than 3 years of age at diagnosis with stage III Wilms tumor by virtue of microscopic residual disease after surgery and whose lymph nodes were not involved by tumors. They were followed with bimonthly abdominal ultrasound examinations to assess local control. Follow-up is now from 2 to 12 years (median 6 years) and 7 of the 8 children are alive and well with no abdominal recurrence. One child relapsed in the lungs and despite further treatment died of progressive disease. The disease-free survival (DFS) and overall survival (OS) are therefore both 87.5%. The DFS and OS in this admittedly small sample are consistent with the survival rates for stage III FH Wilms tumor in the first United Kingdom Children's Cancer Study Group (UKCCSG), North American (NWTS), and European (SIOP) Wilms Tumor studies, Larger numbers of patients are needed to determine whether or not this treatment approach is generally applicable, but we conclude that some children in this stage III "substage" may be treated successfully without radiotherapy.