Malignant Peripheral Nerve Sheath Tumors: A Single Institution's Experience Using Combined Surgery and Radiation Therapy

Purpose: The purpose of this study is to investigate local control (LC), survival outcomes, and associated prognostic factors for patients with malignant peripheral nerve sheath tumors (MPNSTs) treated with combined surgery and radiation therapy (RT). Methods: We reviewed the medical records of 71 consecutive patients treated with surgery and RT for localized MPNST between 1965 and 2012. Preoperative RT was used to treat 23 patients (32%) to a median dose of 50 Gy (range, 50 to 60 Gy), whereas 48 (68%) received postoperative RT to a median dose of 64 Gy (range, 45 to 70 Gy). Results: Median follow-up for living patients was 118 months (range, 21 to 512 mo). The 5-year LC, distant metastatic free survival, and disease-specific survival rates were 84%, 62%, and 66%, respectively. To identify predictors of outcome, several multivariate models were constructed: (1) positive/uncertain surgical margin status was the only factor adversely associated local relapse at 5 years (28% vs. 5% for negative margins; P=0.02; hazard ratios 5.92; 95% confidence interval, 1.3-27.4). (2) No factors were significantly associated with distant metastatic free survival. Of the 35 patients (49%) who sustained disease relapse, only 3 were ultimately salvaged. Only 2 patients had grade 2 late toxicities (necrosis, fibrosis) based on Common Terminology Criteria for Adverse Events version 4.03 criteria, and 1 patient had grade 1 edema. Conclusions: Combination therapy with surgery and RT provides favorable LC. Distant recurrences, however, continue to be challenging with limited salvage success at the time of relapse.