LAttice Radiation Therapy for Large Lesions: Reggio Emilia Single-arm Phase II Trial

This study evaluates the activity and toxicity of Lattice Radiation Therapy (LRT) in patients with large, unresectable non-brain neoplastic lesions requiring palliative treatment. Eligible patients will 5 fractions LRT, delivered in every other day, to 20 Gy with a simultaneous boost to a minimum median dose of 50 Gy. No concomitant antineoplastic drugs will be allowed. Patients will be followed at 14, 30, 60, and 90 days after treatment, then every 3 months up to 1 year. Tumor response will be assessed using objective response rate (ORR) per RECIST 1.1, with CT scans at 3, 6, 9, and 12 months. Secondary endpoints include local control, toxicity (CTCAE v.5.0), and patient-reported outcomes (PROMs) to assess their quality of life (EORTC QLQ-C15-PAL and PRO-CTCAE). Exploratory objectives will assess the immunomodulatory effects of LRT through immune cell characterization and quantification of immune-related circulating factors before and after treatment.