ESTRO 2023 - Abstract Book

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ESTRO 2023

1 Hospital Universitario de Badajoz, Radiation Oncology, Badajoz, Spain; 2 Hospital Universitario Badajoz, Radiation Oncology, Badajoz, Spain; 3 Hospital Universitario Torrecardenas , Radiation Oncology, Almeria, Spain; 4 Hospital Universitario de Badajoz, Radiophysics , Badajoz, Spain Purpose or Objective Brain metastasis are the most frequent tumor of CNS in adult population. It represents between 20% to 40% in oncological patients along their life. Their treatment is one of the challenge to get better overall survival and quality of life. Since RTOG study, radio surgery in only one fraction or multi fraction (HSRS) for metastasis >2cm is the standard of care in patients with limited brain metastasis and good performance status. To analyze the results in terms of overall survival, local or distance recurrence and associated toxicities, this study was realized. Materials and Methods This retrospective study, analyses 53 brain metastasis in 39 patient treated in our hospital between July 2019 and June 2022 with a median age of 61 years (30-87). The metastasis were treated with HSRS scheme of treatment between 3 to 10 fractions, every the other day or in consecutive days when the number of fractions were more than five. The 16% of the metastases were located in cerebellum, 84% supratentorial metastases. The 34,6% of the metastasis included were post-surgical cavities with complete resection and the 65% were intact brain metastasis. The median volume of GTV was 12,94 mL (0,04-130mL). The protocol includes surveillance with MRI in the 4 weeks before radiation treatment, as well as one MRI at 4-6 weeks after the last fraction of radiation therapy, and then, each 3 months during the next two years. To analyses overall survival and time to progression free survival, Kaplan Meier curves was used. Logistic regression multivariate was used to analyze the relationship between GTV volume and side effects, and between overall survival with any dose or side effects, specially edema symptomatic or radiologic during the surveillance. Results At follow up time of 31 months, we have observed an overall survival of 15%. The local failure was 36,5% and the 30,4% of the patients presented distance failure at the moment of the analyses. One patients presented recurrence disease in the radiation field, which was treated with surgery resection. The histology most frequent is NSCLC (61.5%). The 83.3% of the metastases did not have any side effects, 3.7% presented during the followup radio necrosis in MRI, without symptoms associated. Only one patient presented symptomatic edema. Not significant statically relationship was observed between GTV volume (p 0.125) or total dose (p 0.135) and the incidence of edema. Conclusion The treatment of limited brain metastases with multi fraction radiosurgery is a safe option, which reduce the side effects and the risk of neurological impairment in oncological patients with good performance status. The risk of recurrence in other location inside the brain is high, and narrow followup with MRI each 3 months is necessary. In our experience the risk of edema or radionecrosis is low, and in the cases in which were appeared, the treatment with low doses of steroids were enough to control the symptoms. 1 National Center for Oncological Hadrontherapy (CNAO), Clinical Department, Pavia, Italy; 2 University of Milan Bicocca and San Gerardo Hospital, Department of Radiation Oncology, Monza, Italy; 3 University of Milan, Department of Oncology and Hemato-oncology, Milan, Italy; 4 National Center for Oncological Hadrontherapy (CNAO), Clinical Department , Pavia, Italy Purpose or Objective Brain meningiomas (BM) are typically located near critical organs at risk. Protons (PT) have favorable physical and radio biological properties to spare normal brain tissue, decreasing the dose delivered to the non-target tissues. So, PT is considered a promising alternative to photon radiotherapy. Hence, here we present a monocentric report of BM patients (pts) treated with PT focusing on disease control, survival endpoints and toxicity treatments-related analysis. Materials and Methods We reviewed data from 168 pts with a clinical history of BM treated with PT from January 2014 to December 2021 and prospectively followed-up. Reirradiation cases were excluded. PT was delivered conventionally (Figure 1), with a pencil beam-scanning technique. Endpoints evaluated are local control (LC) and progression-free survival (PFS) using Kaplan-Meier method. Radiation induced AEs (RIAEs) were reported according to Common Terminology Criteria for Adverse Events (CTCAE)v5.0. RIAEs were analyzed into different domains: optic ways, other cranial nerves, pituitary, skin and brain.Relationships between late RIAEs>G2 and other parameters were analyzed using Fisher’s exact test. PO-1126 Effectiveness and safety of proton therapy for brain meningiomas: a monocentric experience L.P. Ciccone 1 , G. Riva 1 , S.P. Bianchi 2 , M. Rotondi 3 , S. Russo 4 , A. Iannalfi 1 , E. Orlandi 1