RADT-14. ROLE OF CHEMOTHERAPY AFTER RADIATION THERAPY FOR GYNECOLOGIC METASTASES TO THE BRAIN

Abstract

Abstract BACKGROUND Brain metastasis from gynecologic malignancy is rare, and the optimal treatment is undetermined. METHODS Retrospective data was collected at a single institution from 2001-2021 on 66 patients with brain metastasis from gynecologic malignancy who underwent brain radiation therapy (RT). Kaplan-Meier survival analyses, long-rank tests, and a multivariate proportional hazards model were performed. RESULTS Median overall survival (OS) and intracranial progression-free survival (PFS) were 4.3 and 3.6 months, respectively. 25 (38%) patients started chemotherapy after RT in a median 32.5 days (IQR 12-53). Compared to those who did not start chemotherapy after RT, those who did had a longer median OS (9.8 vs 2.6 months, p < 0.01) and PFS (5.0 vs 2.5 months, p = 0.01). On univariate analysis, factors associated with worse survival included >10 brain metastases (p = 0.09), leptomeningeal involvement (p < 0.01), presence of extracranial disease (p = 0.01), no receipt of surgery (p = 0.05), receipt of whole brain RT (p < 0.01), and no receipt of chemotherapy after RT (p < 0.01). On multivariate analysis including above factors and age-adjusted Charlson Comorbidity Index, only receipt of chemotherapy after RT was significantly associated with improved survival (HR 0.32, CI 0.16-0.64). The most common chemotherapy was platinum-based agents in 10 (40%) patients, with no difference in survival (p = 0.74) between those treated with platinum-based versus other agents. More patients who started chemotherapy after RT compared to those who didn’t had ovarian cancer (56 vs 22%, p = 0.02), underwent surgery (52 vs 29%, p = 0.07), and underwent stereotactic radiosurgery (SRS) (64 vs 27%, p < 0.01). For patients who did vs did not receive chemotherapy after SRS, median OS was 11.3 vs 4.3 months (p = 0.01), and after WBRT 4.5 vs 2.2 months (p = 0.10). CONCLUSION Patients treated with chemotherapy after SRS in this population may have improved outcomes, though prognosis remains poor.