CMET-03. MANAGEMENT OF MULTIPLE BRAIN METASTASES BY STAGED SRS FOCUSING ON UTMOST RISK LESIONS

Abstract

Abstract BACKGROUND Patients with multiple large brain metastases (LBMs) are subject to cause intracranial hypertension, which remains a clinical difficulty so far. The present study is to investigate whether staged stereotactic radiosurgery (SRS) is a feasible solution to improve clinical symptoms and life quality in palliative management. METHODS Patients with brain metastases treated between 1 January 2016 and 30 March 2019 were retrospectively studied. The patients inclusion criteria included were: 1) metastatic lesions ≥ 3; 2) tumor lesions with a supratentorial invasion ≥ 3 cm or a subtentorial invasion ≥ 2 cm; 3) with neurological impairment or with a high risk for intracranial hypertension. The first stage of SRS dose regimens for utmost risk supratentorial lesions were 20-24Gy within 2-fractions (fx); whereas 24Gy/3-fx for subtentorial lesions. For the 2nd stage, the rest metastatic lesions with relatively lower risk were treated with 16-18Gy/1-fx one week after that. RESULTS A total of 30 patients were enrolled included in this study. The neurological symptoms were significantly relieved following 1st stage of SRS, with a median period of 3 days (2–14 days). 13 out of 30 patients were randomly selected for MR imaging two weeks after SRS. It suggested that 84.6% (11/13) of the patients were observed with a clear reduction of tumor volume. The median reduced diameter was 0.38 (0.17–0.83) cm and a median volume reduction was 3.22 (0.01–9.08) mm3. According to RANO-BM, the objective remission rate of utmost risk lesions was 100%, whereas the less critical lesions was 95.16% (59/62). One patient (3.33%) was identified with acute adverse reaction (> grade 3). CONCLUSIONS Staged SRS with a priority for utmost risk lesions was indicated to be an effective approach for multiple large brain metastases. Further prospective study is highly warranted.