Local Control Outcomes Using Stereotactic Body Radiation Therapy or Surgical Resection for Metastatic Sarcoma

Purpose: Traditional management of metastatic sarcoma primarily relies on systemic therapy, with surgery often used for tumor control. We analyzed the rates of recurrence, overall survival, and treatment complications in patients undergoing either surgical resection or stereotactic body radiation therapy (SBRT) for metastatic sarcoma of the bone and/or soft tissue.

Methods and materials: The records of patients with metastatic sarcoma between 2009 and 2020 were reviewed. Local recurrence (LR) was defined as tumor growth or recurrence at the tumor site. Cumulative LR incidence was analyzed accounting for the competing risk of death, and groups were compared using the Gray test. Overall survival (OS) was assessed using the Kaplan-Meier method and log-rank test. Hazard ratios were determined using the Cox proportional hazards model.

Results: A total of 525 metastatic lesions in 217 patients were analyzed. The mean age of patients was 57 years (range, 4-88 years). The lung was the predominant site treated (50%), followed by intra-abdominal (13%) and soft tissue (11%). Two-year cumulative incidences of LR for surgery and SBRT were 14.8% (95% confidence interval [CI], 11.6%-18.5%) and 1.7% (95% CI, 0.1%-8.2%), respectively (P = .003). Local recurrence occurred in 72 (16.5%) of 437 tumors treated with surgery and 2 (2.3%) of 88 tumors treated with SBRT. The adjusted hazard ratio for LR of lesions treated surgically was 11.5 (P = .026) when controlling for tumor size and tumor site. Median OS was 29.8 months (95% CI, 25.6-40.9 months). There were 47 surgical complications among a total of 275 procedures (18%). Of 58 radiation treatment courses, radiation-related toxic effects were reported during the treatment of 7 lesions (12%), and none were higher than grade 2.

Conclusions: We observed excellent local control among patients selected for treatment with SBRT for metastatic sarcoma, with no evidence of an increase in LR after SBRT compared with surgical management. Further investigation is necessary to better define the most appropriate local control strategies for metastatic sarcoma.