Preoperative Versus Postoperative Radiotherapy in Soft-Tissue Sarcoma: Multi-Institutional Analysis of 821 Patients

Abstract

To assess the impact of radiotherapy (RT) sequencing with surgery on overall survival (OS), cause-specific survival (CSS), local failure, and distant failure in soft-tissue sarcoma (STS). A retrospective analysis was conducted using the National Oncology Database, a proprietary database of aggregated tumor registries owned by IMPAC Medical Systems (Sunnyvale, CA). Patients with STS of all major anatomic sites who received definitive surgery and either preoperative (preop) or postoperative (postop) RT were included. Patients were also required to have known stage and grade. Prognostic factors for survival were identified using multivariate techniques. Survival was calculated using the Kaplan-Meier method, and compared for statistical significance (p < 0.05) using the log-rank test. A total of 821 patients met inclusion criteria. The median follow-up time was 63 months. Age, stage, histology, gender, tumor size, and RT sequence were independent predictors for OS (p < 0.05). Preop RT was associated with significantly improved OS and CSS compared with postop RT (hazard ratio [HR] = 0.72, 95% confidence interval [CI] 0.56-0.91, p < 0.01, and HR = 0.64, 95% CI 0.46-0.88, p < 0.01, respectively). The 5-year CSS was 79% and 74%, in favor of preop RT (log-rank, p < 0.05). Preop RT was also significantly associated with a reduced risk for local and distant relapse compared with postop RT. Preoperative RT is associated with a reduced cancer-specific mortality compared with postoperative RT in STS. The results of this study may serve as motivation to conduct future prospective studies with larger patient numbers.