Intraoperative electron beam radiation therapy for retroperitoneal soft tissue sarcoma.

From December 1981 to December 1989, 20 patients with primary or recurrent retroperitoneal sarcoma received 4000 to 5000 cGy of external beam radiation therapy (EBRT) in conjunction with surgical resection and intraoperative radiation therapy (IORT). Seventeen of 20 patients underwent complete (14 patients) or partial (3 patients) resection. Three patients had shown evidence of metastases after EBRT by the time of surgery. The 4-year actuarial local control and disease-free survival rates of the 17 patients undergoing resection were 81% and 64%, respectively. Twelve patients received IORT at the time of resection for microscopic disease (10 patients) or gross residual sarcoma (2 patients). Of the ten patients receiving IORT for microscopic tumor, one patient has died of local failure and peritoneal sarcomatosis and two patients have died of distant metastases only. The remaining seven patients are disease-free. One patient treated for gross residual sarcoma has experienced a local failure 1 year after IORT and is without disease 7 years after salvage chemotherapy. The other patient treated for gross residual sarcoma has died of local failure. Five patients did not receive IORT at the time of resection because of the extensive size of the tumor bed. Three of these patients are disease-free with one patient alive with lung metastases and one patient dying of hepatic metastases. Aggressive radiation and surgical procedures appear to provide satisfactory resectability and local control with acceptable tolerance.