OBJECTIVES: I. Determine the incidence of spontaneous regression of localized neuroblastoma in infants. II. Determine how many infants with neuroblastoma do not need chemotherapy. III. Evaluate the time course of regression by radiologic criteria and catecholamine metabolites. IV. Determine the reliability of risk estimation by molecular characteristics (N-myc amplification, CD44, del 1p) compared to clinical criteria. V. Evaluate whether reduced therapeutic toxicity results in a decrease in treatment-related deaths. VI. Correlate cytostatic drug levels with chemotherapy side effects.