The radiation dose-response of non-retroperitoneal soft tissue sarcoma with positive margins: An NCDB analysis.

Objectives: Positive margins can increase the risk of local recurrence of soft tissue sarcomas (STS). Utilizing a national registry, we investigated patterns of care and overall survival (OS) of patients with margin-positive non-retroperitoneal STS who received preoperative radiation therapy, adjuvant radiation therapy, or both.
Methods: Adult patients with non-retroperitoneal STS who underwent resection and RT from 2004 to 2015 were included. Kaplan-Meier, log-rank analysis, and Cox regression analysis were performed.
Results: We identified 5726 patients. Most had a tumor size >5 cm (60%), grade 3 disease (67%), and microscopically positive margins (57%). Compared to ≤50.4 Gy, a dose of 66 to 69.99 Gy was associated with decreased risk of death on multivariate analysis (HR 0.69, 95%; CI, 0.50-0.94). Receipt of a boost was associated with decreased risk of death on univariate analysis (HR 0.54, 95%; CI, 0.29-0.99). In patients with grade 2 to 3 tumors without the gross disease, there was an OS benefit associated with a boost on multivariate analysis (HR 0.39, 95%; CI, 0.16-0.97).
Conclusion: This analysis appears to show an OS benefit of dose escalation to 66 to 69 Gy for margin-positive non-retroperitoneal STS. A Postoperative boost is associated with higher OS in grade 2 to 3 STS without the gross disease.
(© 2019 Wiley Periodicals, Inc.)