External beam and intraoperative electron irradiation for locally advanced soft tissue sarcomas

Intraoperative irradiation with electrons was used in conjunction with external beam irradiation and maximal surgical resection in 20 patients with locally advanced soft tissue sarcomas or desmoids. This manuscript presents results with regard to tolerance of treatment and its impact on tumor control and survival.

Ten patients presented with previously untreated primary sarcomas and 10 at the time of local recurrence (two had recurrent desmoid tumors). Tumor location was retroperitoneal in 19 and in the low anterior neck in one. A partial or gross total resection was performed prior to the external beam or intraoperative component of irradiation in every patient, but all had positive resection margins. Patients received 4500-6000 cGy of fractionated, external beam irradiation and an IORT dose of 1000-2000 cGy. Chemotherapy was given only at the time of disease progression.

Fourteen of 20 patients (70%) were alive; 11 (55%) were free of disease (4/10 primary, 7/10 recurrent), but 1 required hemipelvectomy for salvage. Progression within the intraoperative irradiation field was documented in only 1 patient (5%) and within the external beam field in 3/20 (15%). Blood born distant metastasis occurred in 5 patients (25%) and peritoneal seeding in 1 (5%). The distant failure incidence by grade was 1/8 (13%) for Grades 1, 2 and 5/12 (42%) for Grades 3, 4. Only 1 patient (5%) developed a > or = severe neuropathy, and small bowel obstruction requiring exploration also occurred in a single patient.

In view of acceptable tolerance and the high current rate of local tumor control, in spite of incomplete surgical resections, further evaluation of intraoperative irradiation as a component of treatment is indicated for locally advanced primary and recurrent soft tissue sarcomas.