Excellent local control with preoperative radiation therapy, surgical resection, and intra-operative electron radiation therapy for retroperitoneal sarcoma.

PURPOSE To examine the value of surgical resection combined with preoperative external beam radiation therapy and intraoperative radiation therapy (Surg-RT) for retroperitoneal sarcoma (RPS). METHODS Review of 63 consecutive patients with RPS from 1996 to 2011. RESULTS Thirty-seven patients (59%) underwent Surg-RT and 26 (41%) had surgery alone. 51% of tumors were high grade and 36% of patients had locally recurrent disease. Final margin status was: R0 73%, R1 16%, R2 6%, and unknown 5%. Of those with R0 resections, 67% received Surg-RT. Median follow-up was 45 months. The 5-year local control rate was 89% for Surg-RT patients and 46% for surgery alone patients (P = 0.03). On multivariate analysis, Surg-RT was the only variable associated with a lower risk of LR (HR 0.19; CI 0.05-0.69, P = 0.003). The actuarial 5-year OS was 60% for patients receiving either Surg-RT or surgery alone. CONCLUSIONS The combination of pre-operative radiation, surgical resection, and intraoperative radiation produces excellent local disease control for RPS. Combination therapy was associated with improved local control but not with overall survival.