Stage II neuroblastoma--does adjuvant irradiation contribute to cure?

Twenty-one children with Stage II neuroblastoma diagnosed between 1973 and 1983 were analyzed retrospectively. Median age at diagnosis was eleven months (1 week to 153 months). Primary tumor was above the diaphragm in 67% and below the diaphragm in 33%. All patients underwent surgical resection and pathologic diagnosis was neuroblastoma in 76% and ganglioneuroblastoma in 24%. Regional lymph nodes were positive in three of eleven patients sampled. Sixty-seven percent had gross residual disease, and thirty-three percent had microscopic residual disease. Seventeen patients received postoperative irradiation and none has relapsed (median follow-up 57 months). Four patients received surgery alone (median follow-up 24 months); one local relapse occurred in this group and was subsequently treated with irradiation. All patients are alive and disease free, with a median length of follow-up of 55 months. Radiation dosage was 1000-1800 rad in patients less than 12 months of age, and 1800-3000 rad in those greater than 12 months of age at diagnosis. The high disease-free survival rate in both groups of patients, but especially in the group receiving adjuvant irradiation, emphasizes the need for a controlled, prospective study to determine which Stage II neuroblastoma patients, if any, would be benefitted by postoperative irradiation.