Comparison of Perioperative Radiation Therapy and Surgery Versus Surgery Alone in 204 Patients With Primary Retroperitoneal Sarcoma A Retrospective 2-Institution Study

Objective: To compare outcomes of patients with retroperitoneal or pelvic sarcoma treated with perioperative radiation therapy (RT) versus those treated without perioperative RT. Background: RT for retroperitoneal or pelvic sarcoma is controversial, and few studies have compared outcomes with and without RT. Methods: Prospectively maintained databases were reviewed to retrospectively compare patients with primary retroperitoneal or pelvic sarcoma treated during 2003-2011. Multivariate Cox regression models were used to assess associations with the primary endpoints: local recurrence-free survival (LRFS) and disease-specific survival. Results: At 1 institution, 172 patients were treated with surgery alone, whereas at another institution 32 patients were treated with surgery and perioperative proton beam RT or intensity-modulated RT with or without intra-operative RT. The groups were similar in age, tumor size, grade, and margin status (all P > 0.08). The RT group had a higher percentage of pelvic tumors (P = 0.03) and a different distribution of histologies (P = 0.04). Perioperative morbidity was higher in the RT group (44% vs 16% of patients; P = 0.004). After a median follow-up of 39 months, 5-year LRFS was 91% (95% confidence interval, 79%-100%) in the RT group and 65% (57%-74%) in the surgery-only group (P = 0.02). On multivariate analysis, RT was associated with better LRFS (hazard ratio, 0.26; P = 0.03). Five-year disease-specific survival was 93% (95% confidence interval, 82%-100%) in the RT group and 85% (78%-92%) in the surgery-only group (P = 0.3). Conclusions: The addition of advanced-modality RT to surgery for primary retroperitoneal or pelvic sarcoma was associated with improved LRFS, although this did not translate into significantly better disease-specific survival. This treatment strategy warrants further investigation in a randomized trial.