The impact of delayed surgery on radiotherapy dose and local control of rhabdomyosarcoma.

To determine if delayed surgery permits the modification of radiotherapy dose while maintaining local control in children with localized, unresectable rhabdomyosarcoma, a prospective study was launched in 1981 to test this objective. Treatment consisted of 16 weeks of preoperative chemotherapy, with or without delayed surgery, and radiotherapy using 35 to 40 Gy (3500 to 4000 rad) for microscopic and 50 to 55 Gy (5000 to 5500 rad) for gross residual tumor, plus 14 months of chemotherapy. Among 22 patients treated, surgery was feasible in 11 of 14 patients with residual tumor after chemotherapy and was performed in eight (avoiding radical surgery in three), leaving microscopic (seven patients) or gross residual (one patient) tumor. Progressive disease or amputation precluded radiotherapy in two patients. After radiotherapy local control was sustained in 12 of 14 patients with microscopic lesions vs none of six patients with gross tumor. Delayed surgery may permit the use of lower-dose radiotherapy and should be considered in the treatment plan for this subset of patients.