ESTRO 2023 - Abstract Book

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ESTRO 2023

p=0.011), the presence of at least one infratentorial BM (HR: 1.477, p=0.006) and progression disease at first control (HR: 2.433, p<0.001) negatively affected OS, while female gender (HR: 0.626, p=0.001) had a positive impact.

Conclusion SRS and fractionated stereotactic radiotherapy represent a feasible and effective treatment option for patients with BMs from NSCLC. The SRS dose and concomitant systemic therapy have a major impact on LC. On the other hand, the need for CST before SRS, the infratentorial involvement from BMs, a high tumor burden (>1 BM at the time of treatment or an overall treated volume >3 cc) and a non-responsive lesion to SRS had a negative impact on OS.

PO-1131 Proton and carbon ion therapy for intracranial meningioma after previous brain radiotherapy

G. Riva 1 , L.P. Ciccone 1 , S.P. Bianchi 2 , S. Russo 1 , A. Iannalfi 1 , E. Orlandi 1

1 National Center for Oncological Hadrontherapy, Clinical Department, Pavia, Italy; 2 University of Milan Biccocca and San Gerardo Hospital, Department of Radiation oncology, Monza, Italy Purpose or Objective Meningiomas represent up to 30-40% of primary brain tumors and most of them show high rates of control after conventional therapies. Despite generally favorable outcomes, progression after RT occurs with few options for salvage treatment. Moreover, the onset of meningiomas should be related to radiation exposure for other pathologies, especially in pediatric age. In these cases, re-RT is often difficult due to the limited radiation tolerance of the surrounding organs at risk (OARs). The aim of this study is to evaluate the feasibility and safety of re-RT with PT and CIRT for meningiomas. Materials and Methods We reviewed data from patients who received brain re-RT with PT and CIRT for meningioma from 2013 to 2021 in our institute, after previous brain RT and prospectively followed-up. Endpoints evaluated included local control (LC), distant relapse-free survival (DFS) and progression-free survival (PFS) and were estimated since initiation of radiotherapy using the Kaplan-Meier method; p values were calculated using Fisher’s exact test. Toxicity was reported according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Results Sixty-nine patients treated with PT (n = 48, 70%) or CIRT (n = 21, 30%) for recurrent or RT-induced meningioma were included in this analysis. Table 1 shows the demographic and clinical characteristics of the patients while in table 2 data of particle therapy are reported. Median follow-up was 20 months (range, 3-99). 2-y and 4-y LC was 78.8% and 55.0%, There was no significant difference between recurrent and RT-induced meningiomas in terms of LC (p = 0.71), DFS ( p = 0.71) and PFS (0.49) Acute G3 toxicity was reported in 2 (3%) cases and late G3 toxicity in 2 (3%) patients (optic nerve disorder and new onset of seizure without radiologic diagnosis of radionecrosis). CNS necrosis occurred in 19 (28%) cases: 7, 11, and 1 patients developed G1, G2 and G3 radionecrosis, respectively. No acute and late G4-G5 toxicities were observed.