Toxic deaths in the Second National Wilms' Tumor Study.

There were 122 deaths among 803 children registered, randomized, and followed in the second National Wilms' Tumor Study; 17 occurred in children apparently free of disease and were attributable to causes other than tumor progression. Seven deaths were attributed to infection during periods of drug-induced leukopenia; four were due to liver failure; and one each was attributable to radiation pneumonopathy, intestinal obstruction, renal failure, myocardial disease, and encephalopathy. The cause of one death was unexplained. Of particular concern were four (of 47) infants under one year of age with group I or II disease who had toxic deaths. Subsequent to these experiences the doses of all chemotherapeutic agents were reduced by 50% for infants under one year of age. No deaths from toxicity were observed thereafter in infants. An analysis of the therapeutic effect of this dose reduction showed three of 47 relapsed on full dose and five of 54 on half dose. The difference is not statistically significant. This report is a further demonstration of the potentially serious vulnerability of infants to standard doses of anticancer drugs even when they are calculated on a per kilogram basis.