Outcomes Following Combined Modality Treatment to the Primary Site in Select Patients With Metastatic Soft Tissue Sarcoma

Abstract

Purpose: Select patients with metastatic soft tissue sarcoma (STS) may benefit from more aggressive treatment of their primary tumor. We report on the use of combined modality treatment (CMT) using preoperative radiation therapy (RT) followed by surgery to improve local control.

Methods and materials: We retrospectively reviewed the data of 19 patients with metastatic STS consecutively treated at our institution with CMT between 2018 and 2023. All patients received moderately hypofractionated 40.05 Gy in 15 fractions followed by surgery. Patients were selected for CMT based on factors that were likely to predict longer survival despite having metastatic disease such as oligometastatic disease (≤5 lesions) and favorable response to systemic therapy.

Results: The median size of the primary tumor was 7.6 cm (IQR, 4.4-12.7 cm). Fourteen patients (74%) received systemic therapy immediately before (n = 10) or after (n = 4) CMT. Seven patients (37%) underwent additional metastasis-directed local therapy following CMT to other sites. Pain reduction after CMT was documented in 89% of patients who presented with pain (n = 8 of 9). Median follow-up was 21 months. Two-year local recurrence-free survival, progression-free/distant recurrence-free survival, and overall/cancer-specific survival were 92%, 29%, and 65%, respectively. One patient (5%) had local recurrence. For patients who were not planned to have adjuvant systemic therapy, median systemic therapy-free survival was 15 months. The rate of wound complications within 120 days of surgery was 16%. No planned adjuvant therapy was delayed because of wound complications; all patients commenced systemic therapy within 3 months of surgery. The rate of late RT toxicities was 26%; there were no grade ≥3 late toxicities.

Conclusions: For properly selected patients with metastatic STS with good performance status and long expected survival, a CMT strategy for the primary tumor with moderately hypofractionated preoperative RT offers favorable local control, low toxicity, and pain mitigation without significant effect on systemic therapy resumption.