ESTRO 2023 - Abstract Book

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ESTRO 2023

53% of RN were symptomatic; 83% of the RN in the MF-SRS group and 46% of the RN in the SF-SRS group. Univariate analysis showed that receiving SF-SRS (OR 3.5, 1.4-9) or prior WBRT (OR 5.2, 1.1-24.1) were predictors of developing RN. We found no relationship between histology or dose received and RN (p=0.8). Patients with RN had higher V10 mean and V12 mean, but without significant differences: V10 10cc vs 8cc and V12 7cc vs 6cc. After a median follow-up of 4 years, the median OS was 2.5 years (1-5) and the median RN free survival was 2.8 years (1.8 5.4). The estimated RN free survival in the MF-SRS group at 1, 3 and 5 years was 94% (8-98), 91% (78-96) and 76% (34-93) and in the SF-SRS group was 78% (68-85), 64% (49-76) and 42% (20-63) respectively (p=0.02).

Conclusion RN is related to lesion size, SF-SRS and previous WBRT.

The lesion diameter with the highest sensitivity and specificity to develop RN was 15mm. Approximately, half of RN were symptomatic, related to having received MF-SRS.

PO-1111 Robotic stereotactic radiotherapy for ≥ 10 brain metastases treated with single treatment planning.

M. Torrisi 1,2 , C. Chissotti 1,2 , C.L. Deantoni 1 , A. Fodor 1 , F. Ferrario 1,2 , L. Giannini 1,2 , M. Midulla 1,2 , S. Broggi 3 , R. Tummineri 1 , I. Dell'Oca 1 , R. Castriconi 3 , F. Zerbetto 1 , C. Fiorino 3 , S. Arcangeli 4,2 , N.G. Di Muzio 1,5 1 IRCCS San Raffaele Research Institute, Department of Radiation Oncology, Milan, Italy; 2 Università degli studi Milano Bicocca, School of Radiation Oncology, Milan, Italy; 3 IRCCS San Raffaele Research Institute, Medical Physics, Milan, Italy; 4 ASST Monza, Department of Radiation Oncology, Monza, Italy; 5 Università Vita Salute San Raffaele, School of Medicine and Surgery, Milan, Italy Purpose or Objective Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) are effective treatments for patients with multiple brain metastases. Here we report our experience with single treatment planning SRS/SRT delivered with CyberKnife® (Accuray, Sunnyvale, CA) in pts with more than 10 brain metastases. Materials and Methods From 06/2018 to 08/2022 a total of 524 brain metastases in 24 pts (four of them treated twice) were treated with a single treatment plan SRS (10 pts) or SRT (6 pts with 3 fractions and 12 pts with 5 fractions) in our institution. Patient’s median