S928
Clinical - Mixed sites & palliation
ESTRO 2026
median total dose of 27Gy/3fractions. Clinical, radiological, and survival data were prospectively collected and retrospectively analyzed. Results: Between June 2015 and May 2018, a total of 260 patients were included. Patient and tumor characteristics are summarized in Table 1. Two-year LC, BDF, and OS rates were 87%, 50.4%, and 49.5%, respectively, confirming durable efficacy at long-term follow-up. New BMs developed in 51 patients (50.5%), among whom 20 (19.8%) experienced leptomeningeal dissemination. In patients with LMD, the median, 6- month, 1,2-year OS were 16 months, 95%, 75%, and 20%, respectively. In contrast, patients without LMD had a median, 6-month, 1,2-year OS of 20 months, 93%, 80.6%, and 38.7%, respectively. Tumor volume (p=0.0252), lesion diameter (p=0.0131), and presence of LMD (p=0.0133) were significant predictors of OS. Logistic regression analysis identified infratentorial location (p=0.0480), and meninges not removed during surgery (p=0.0196) as independent risk factors for LMD. Radionecrosis occurred in 36 patients, being grade 2 in 25 (24.7%) and grade 3 in 11 (10.9%) cases. Neurocognitive function remained stable or improved in most patients.
suggest that deformable dose registration tracked to the subsequent BM volumes would be relevant in the planning of metachronous BMs and, in case of a complete response, the prior dose can be considered irrelevant. Keywords: radiosurgery, volumetric, response
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Leptomeningeal spread after surgery plus radiosurgery to surgical bed for large brain metastases. Is it time to move toward preoperative radiosurgery? Pierina Navarria 1 , Mariya Boianova Ilieva 1 , Federico Pessina 2 , Elena Clerici 1 , Giuseppe Minniti 3 , Paola Anselmo 4 , Silvia Chiesa 5 , Isacco Desideri 6 , Luca Raspagliesi 2 , Marco Marzo 1 , Giacomo Reggiori 1 , Enrico Pozzo 1 , Stefano Tomatis 1 , Ciro Franzese 1 , Marta Scorsetti 1 1 radiotherapy and radiosurgery, Humanitas Research Hospital, Rozzano, Italy. 2 Neurosurgery, Humanitas Research Hospital, Rozzano, Italy. 3 radiotherapy, Policlinico Umberto I, Roma, Italy. 4 radiotherapy oncology center, S.Maria Hospital, Terni, Italy. 5 Radiation Therapy, policlinico Gemelli, roma, Italy. 6 Radiation Therapy, Careggi, Firenze, Italy Purpose/Objective: The occurrence of leptomeningeal disease (LMD) following surgical resection and adjuvant stereotactic radiosurgery (SRS) to surgical cavity in patients with large brain metastases (BMs) represents a major clinical concern, often leading to neurological decline and reduced survival. Previous studies have reported LMD rates as high as 28% in this setting. This study aimed to assess incidence of LMD in a large cohort of oligometastatic patients treated in several Italian centers with surgical resection followed by hypofractionated stereotactic radiosurgery (HSRS) to tumor bed. Secondary objectives included local control (LC), distant brain failure (BDF), overall survival (OS), and prognostic factors associated with LMD development. Material/Methods: Eligible patients were adults (>18 years) with a histologically confirmed solid tumor, Karnofsky Performance Status (KPS) >70, and oligometastatic disease. Inclusion criteria comprised a single brain lesion ≥ 2.1 cm in maximum diameter, or <2 cm when associated with mass effect, neurological deficits, or significant edema. Surgery was performed aiming at maximal safe resection. Postoperative HSRS was delivered within one month from surgery, with a
Conclusion: Postoperative HSRS following surgical resection of large brain metastases provides excellent local control with acceptable toxicity. However, leptomeningeal disease remains a major determinant of poor prognosis. The present data support consideration of preoperative HSRS as a potentially safer strategy to reduce the risk of LMD, warranting further prospective
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