Lattice SFRT in a geriatric patient with an initially inoperable leg bulky sarcoma: case report and literature review.

BACKGROUND: 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. CASE PRESENTATION: 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. CONCLUSION: 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.