ESTRO 2024 - Abstract Book

S834

Clinical - CNS

ESTRO 2024

Luca Nicosia 1 , Andrea Gaetano Allegra 1 , Niccolò Giaj-Levra 1 , Reyhaneh Bayani 2 , Nima Mousavi Darzikolaee 2 , Rosario Mazzola 1 , Edoardo Pastorello 1 , Francesco Ricchetti 1 , Michele Rigo 1 , Ruggero Ruggieri 1 , Davide Gurrera 1 , Riccardo Filippo Borgese 1 , Simona Gaito 3 , Giuseppe Minniti 4 , Pierina Navarria 5 , Marta Scorsetti 5 , Filippo Alongi 1 1 IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Advanced Radiation Oncology Department, Negrar, Italy. 2 Hamadan university of Medical Sciences, Radiation Oncology Department, Hamadan, Iran, Islamic Republic of. 3 School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Division of Clinical Cancer Science, Manchester, United Kingdom. 4 Oncology and Anatomical Pathology, Sapienza University, Department of Radiological Sciences, Rome, Italy. 5 Humanitas University, Department of Biomedical Sciences, Milan, Italy

Purpose/Objective:

Stereotactic radiosurgery (SRS) is an established non-invasive therapy for multiple brain metastases (BMs). Mono isocentric techniques allow the delivery of multiple stereotactic courses, in the event of intracranial failure. Nevertheless, limited data on the effectiveness and toxicity have been reported, as well as details on patterns of failure. Aim of this study is to evaluate effectiveness and safety of multiple HyperArc courses and patterns of progression in patients affected by BMs with intracranial progression.

Material/Methods:

between June 2017 and January 2022, 56 patients were treated for 702 BMs with 197 (range 2-8) HyperArc courses in case of exclusive intracranial progression. Primary tumor was lung in 26 (46.5%), breast in 18 (32%), melanoma in 8 (14%), and other in 4 (7.5%). BM site was: supratentorial in 529 (75%), infratentorial in 160 (23%), brainstem in 13 (2%). The primary end-point was the overall survival (OS), secondary end-points were intracranial progression-free survival (iPFS), toxicity, local control (LC), neurological death (ND), and WBRT-free survival. Site of progression was evaluated against isodoses levels (0, 1, 2, 3, 5, 7, 8, 10, 13, 15, 20, and 24 Gy.).

Results:

The median SRS dose was 25 Gy (range 24-27 Gy). The 1-year OS was 70%, and the median was 20.8 months (17-36). At the univariate analysis (UVA) BED>51.3Gy and non-melanoma histology significantly correlated with OS. The median time to iPFS was 4.9 months, and the 1-year iPFS was 15%. Globally, 538 new BMs occurred after the first HA cycle in patients with extracranial disease controlled. 95% of them occurred within the isodoses range 0-7 Gy as follows: 27.5% (0 Gy), 19.5% (1 Gy), 16.7% (2 Gy), 16% (3 Gy), 12.5% (5 Gy), 2.8% (7 Gy) (p=0.00). Clinical toxicity was represented by headache 4 (7.1%), and radionecrosis 2 (0.28% of treated metastases). One- and 2-year LC was 90% and 79%, respectively. At the UVA BED>70 Gy and non-melanoma histology were significant predictors of higher LC. The 2-year WBRT-free survival was 70%. After a median follow-up of 20 months, 12 patients deceased by ND (median time 17.4 months).

Conclusion: