Purpose: To determine whether the 50% dose reduction of all chemotherapeutic agents recommended for babies (less than or equal to 12 months of age) by the Third National Wilms' Tumor Study (NWTS-3) produced acceptable toxicity without sacrificing any survival benefit.
Materials and methods: The 365 babies enrolled in NWTS-3 had tumors of varying histologies and stages. The present analysis was restricted to the 256 infants who had tumors of favorable histology, were free of metastasis at diagnosis, and received treatment according to NWTS-3 guidelines.
Results: Despite the recommended attenuation of drug doses observed in 75% of the chemotherapy courses received, outcomes for these babies were comparable to those obtained in older children given full doses of chemotherapy. Four-year survival rates for 256 babies with stages I (n = 199), II (n = 38), and III (n = 19) favorable-histology tumors were 96%, 95%, and 90%, respectively. The figures for 498 stage I, 342 stage II, and 373 stage III older children with favorable-histology lesions were 92%, 94%, and 91% in that order. There were no deaths from hematologic toxicity or infection among babies who received half-dose chemotherapy. The death rates for their older NWTS-3 counterparts was 1%.
Conclusion: Less aggressive therapies advocated for babies in NWTS-3 provide acceptable levels of morbidity without compromising the excellent results previously reported for low-risk patients of all ages.