Role of Spatially Fractionated Radiotherapy (LATTICE) Treatment in Inoperable Bulky Soft-Tissue Sarcomas
Katarina Majerčáková, Natalia Tejedor Aguilar, J. Isern, Helena Vivancos Bargalló, Antonio Vila Capel, Miriam Mancera Soto, G. Gómez de Segura Melcón, Jady Vivian Rojas Cordero, José Antonio González-López, Sílvia Bagué, Diana Hernández Jover, Saba Rabi Mitre, Ana Maestre Peiró, Ana Sebio, Gemma Sancho
Abstract
Background: The clinical outcome of inoperable sarcoma patients treated with LATTICE (LRT) is limited and therefore the objective of our study was to report treatment response, overall survival (OS), local-recurrence free survival (LRFS) and toxicity. Methods: This retrospective observational study includes 15 histologically proven inoperable non-extremity sarcoma patients with no treatment options or no response to systemic therapy, treated at our institution between 2020 and 2024. The patients were treated with a combination of LRT and normo- or hypo-fractionated external beam radiotherapy. Treatment response was evaluated by RECIST1.1 criteria, toxicity by CTCAE 5.0 and OS and LRFS by Kaplan–Meier curves. Results: The median follow-up (F-UP) since the beginning of the treatment was 10 months (range 4–32). Nine patients were male and six female. Their mean age was 60 years. The median gross tumor volume (GTV) was 1058 cm3 (range 142–6103 cm3). The median number of spheres was 9 (4–30). All patients with symptoms reported symptoms’ relief. Based on RECIST1.1 criteria, 10 patients (67%) had stable local disease at 1–2 months F-UP on computed tomography (CT). Surgical resection was feasible in five patients. Three of them are alive without disease and two died due to metastatic progression. From 10 (67%) non operated patients, 5 patients died (50%) due to disease. The remaining five patients (50%) are alive, three with stable disease at 21, 22, and 32 months of F-UP and two with disease progression who are currently receiving palliative chemotherapy treatment. Reported G2 toxicity was as follows: gastrointestinal (2), asthenia (1). Two patients had G3 toxicity: esophagitis (1) and inguinal dermatitis (1). No acute or chronic G4–G5 toxicity was observed. Conclusions: LRT is a feasible and well-tolerated radiation technique for inoperable bulky soft-tissue sarcomas. Further studies are needed to establish protocols to determine which patients could benefit from palliative or preoperative treatment.