ESTRO 2023 - Abstract Book

S907

Digital Posters

ESTRO 2023

toxicity have been reported. Aim of this study was to evaluate effectiveness and safety of multiple HyperArc courses in patients affected by brain metastases (BM) with intracranial progression. Materials and Methods Between June 2017 and January 2022, 56 patients were treated to 702 BM using HyperArc. Patients were treated with HyperArc in case of further intracranial progression. Globally, 198 HA courses were administered (range 2-8). Primary tumor was lung 26 (46.5%), breast (32%), melanoma 8 (14%), and other 4 (7.5%). The median GTV volume was 0.1 cc (range 0.08 21.1 cc). BM site was: supratentorial 529 (75%), infratentorial 160 (23%), brainstem 13 (2%). The primary end-point was the overall survival (OS), secondary en-points were intracranial progression-free survival (iPFS), toxicity, local control (LC), neurological death (ND), and WBRT-free survival. Results The median OS was 20.8 months (17-36). The 1-year OS was 70%. At the univariate analysis (UVA) BED>51.3Gy and non melanoma histology were significantly correlated with OS. The median time to iPFS was 4.9 months, and the 1-year iPFS was 15%. Extracranial progression after HA was significantly correlated with iPFS and the UVA. 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 predictor of higher LC. Salvage WBRT was administered in 13 patients (23.2%), and the 2-year WBRT-free survival was 70%. At the last follow-up 12 patients deceased by ND (median time 17.4 months). Conclusion Intracranical relapse can be safely and efficaciously treated with repeated HyperArc, with a possible survival improvement. Neurological death is a relatively rare event in this population. Systemic treatment and extracranial disease should be considered in the decisional workflow. A future study is planned aiming to evaluate neurocognitive function.

PO-1135 Stereotactic radiotherapy for brain metastasis in patients with non-small cell lung cancer

S. Nagaraja 1 , B. Hültenschmidt 1 , S. Nadji 1 , N. Frank 1 , K. Lindel 1

1 Municipal Hospital Karlsruhe, Clinic for Radiation Oncology and Radiotherapy, Karlsruhe, Germany

Purpose or Objective Stereotactic radiotherapy or radiosurgery (SRT) is being increasingly used either as adjuvant treatment after tumor resection (p.o. SRT) or as definitive therapy (def. SRT) for brain metastasis in patients with non-small cell lung cancer (NSCLC), to optimise the local tumour control and avoid the side effects associated with whole brain radiotherapy (WBRT). In the present study we compare the results of the two above mentioned approaches. Materials and Methods The treatment and follow-up data of 60 patients (34 P. def. vs. 26 p.o. SRT) who were treated at our institute between August 2014 and December 2021 was analyzed. The patient, tumor and treatment characteristics are represented in the table 1. The median age in each group was 62.1 (p.o. SRT) and 68.4 (def. SRT) years with a Karnofsky performance score of 80 and 70%, respectively. Solitary brain metastasis was most common in p.o. SRT group in comparison to 2-3 metastasis in def. SRT group.

Results