Dix DB, Fernandez CV, Chi YY, et al. - Given a link between tumor-specific combined loss of heterozygosity of chromosomes 1p and 16q (LOH1p/16q) and adverse outcomes reported in patients with favorable histology Wilms tumor in the National Wilms Tumor Study 5 (NWTS-5), researchers investigated if improved event-free survival (EFS) for these patients could be achieved by augmenting therapy, in the AREN0533/AREN0532 studies. Regimen DD4A (vincristine, dactinomycin and doxorubicin) but no radiation therapy was administered to patients with stage I/II disease. Regimen M (vincristine, dactinomycin, and doxorubicin alternating with cyclophosphamide and etoposide) and radiation therapy were administered in patients with stage III/IV disease. The 4-year EFS was estimated to be 87.3% and 90.2% for patients with stage I/II and stage III/IV disease with LOH1p/16, respectively. An improved EFS was achieved with augmentation of therapy in patients with favorable histology Wilms tumor and LOH1p/16q vs the historical NWTS-5 comparison group. An expected toxicity profile was evident.