Treatment of children with stage IV favorable histology Wilms tumor: a report from the National Wilms Tumor Study Group.

The purpose of this study was to evaluate the effect of the sequential addition of doxorubicin and cyclophosphamide to the combination of vincristine and actinomycin D on the relapse-free survival of children with stage IV/favorable histology Wilms tumor. We reviewed the clinical courses of all randomized patients from National Wilms Tumor Study (NWTS)-2 and 3 with stage IV/favorable histology (FH) Wilms tumor. We determined the four-year relapse-free survival percentage for patients treated on NWTS-2 with the combination of vincristine (VCR) and actinomycin D (AMD) with (regimen D) or without (regimen C) doxorubicin (DOX), and for patients treated on NWTS-3 with the combination of VCR+AMD+DOX with (regimen J) or without (regimen DD-RT) cyclophosphamide (CTX). All children received whole lung radiation therapy. The four-year relapse-free survival percentage for children with stage IV/FH Wilms tumor treated with regimen C was 53.3%, compared to 57.7% for those treated with regimen D (P = 0.63). The four-year relapse-free survival percentage for children with stage IV/FH Wilms tumor treated with regimen DD-RT was 79.0%, compared to 80.9% for those treated on regimen J (P = 0.79). The four-year relapse-free survival for children with lung metastases only treated with regimen D on NWTS-2 was significantly lower than that of children treated with the related regimen DD-RT on NWTS-3 (P = 0.03). We conclude that the addition of doxorubicin to the combination of vincristine and actinomycin D and pulmonary irradiation did not clearly improve the four-year relapse-free survival percentage of children with stage IV/FH Wilms tumor, although the benefit may have been masked by the greater frequency of death due to toxicity in NWTS-2. There was no evidence that the addition of CTX to the three-drug treatment regimen improved the four-year relapse-free survival percentage of children with stage IV/FH Wilms tumor. The data with only two drugs derived from NWTS-2 suggest that there is a population of children with stage IV/FH Wilms tumor who can be successfully treated without an anthracycline. The goal of future research will be to identify this subgroup at the time of initial diagnosis.