Hypofractionated Radiation Therapy for Unresectable or Metastatic Sarcoma Lesions

Purpose: Given the relative radioresistance of sarcomas and their often large size, conventional palliative radiation therapy (RT) often offers limited tumor control and symptom relief. We report on our use of hypofractionated RT (HFRT) as a strategy to promote durable local disease control and optimize palliation. Methods and Materials: We retrospectively reviewed 73 consecutive patients with sarcoma who received >10 fractions of HFRT from 2017 to 2020. Clinical scenarios included: (1) palliative or symptomatic intent (34%), (2) an unresectable primary (27%), (3) oligometastatic disease (16%), and (4) oligoprogressive disease (23%). Results: The HFRT target was a primary tumor in 64% of patients with a median dose of 45 Gy in 15 fractions (59% ≥45 Gy). The 1-year disease-specific survival was 59%, which was more favorable for patients receiving HFRT for oligometastatic (1-year 100%) or oligoprogressive (1-year 73%) disease (P = .001). The 1-year local control (LC) of targeted lesions was 73%. A metastatic target (1-year 95% vs 60% primary; P = .02; hazard ratio, 0.27; P = .04) and soft tissue origin (1-year 78% vs 61% bone; P = .01; hazard ratio, 0.33; P = .02) were associated with better LC. The rate of distant failure was high with a 6-month distant metastasis-free survival of only 43%. For patients not planned for adjuvant systemic therapy (n = 53), the median systemic therapy break was 9 months and notably longer in oligometastatic (13 months), oligoprogressive (12 months) or unresectable (13 months) disease. HFRT provided palliative relief in 95% of cases with symptoms. Overall, 49% of patients developed acute grade 1 to 2 RT toxicities (no grade 3-5). No late grade 2 to 5 toxicities were observed. Conclusions: HFRT is an effective treatment strategy for patients with unresectable or metastatic sarcoma to provide durable LC, symptom relief, and systemic therapy breaks with limited toxic effects.