Hybrid fractionation and Lattice boost provide pain relief and necrosis in inoperable pleomorphic liposarcomaHybrid Radiation Approach Shows Promise for Inoperable Soft Tissue Sarcoma

Management of inoperable bulky soft tissue sarcomas mostly in geriatric patients presents a significant clinical challenge due to high and hypoxia-induced radioresistance, proximity to dose-limiting Organs at Risk (OARs), and the need to minimize systemic toxicity. Spatially Fractionated Radiation Therapy (SFRT), specifically 3D Lattice Radiation Therapy (LRT), offers a novel approach to safely escalate dose within the tumor volume. 85-year-old female presenting a massive (20.7 x 9.8 cm), inoperable high-grade pleomorphic liposarcoma (FNCLCC Grade 3) of the right thigh. A hybrid fractionation approach was employed, consisting of conventional Volumetric Modulated Arc Therapy (VMAT) (40 Gy in 20 fractions) to the Clinical Target Volume (CTV), concurrently integrated with a weekly Lattice boost of 10 Gy, for 3 times, targeting 4 specific series of spatial vertices (Sup1, Sup2, Inf1, Inf2) using a strip-field technique. Remarkably, physical examination during the fourth week revealed a dramatic reduction in tumor consistency and pain relief. The tailored hybrid treatment was exceptionally well tolerated with no severe acute skin toxicity. The 4-month follow-up MRI showed stable external dimensions with internal coagulative necrosis, allowing adjuvant surgery. This case highlights the feasibility, safety, and tolerability of a response-adapted weekly hybrid LRT approach for bulky extremity sarcomas especially in frail populations. We also provide a brief review of the emerging literature on SFRT/LRT in bulky sarcomas and frail patients.