LMAP-08 MULTI-INSTITUTIONAL CLINICAL OUTCOMES FOLLOWING STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES FROM GYNECOLOGIC MALIGNANCIES

Brain metastases (BM) are rare in patients with gynecologic (GYN) malignancies. We identified and analyzed all patients who completed a course of stereotactic radiosurgery (SRS) between 1/2015 and 12/2020 across two institutions. Demographic and clinical parameters were collected. Intracranial progression (ICP) was defined as any concern on post-SRS imaging for recurrence determined by multidisciplinary consensus. Clinical parameter distributions were compared across GYN and non-GYN patients utilizing chi-squared tests and t-tests. Overall survival (OS) and freedom from intracranial progression (FFICP) were estimated via the Kaplan Meier method. From a cohort of 1383 patients who completed SRS for BMs, 2.4% (n=33) had a BM from a GYN malignancy. Subsites included endometrial (n=19), ovarian (n=11), vulvar (n=2), cervical (n=1). There was no difference in age between GYN and non-GYN patients (mean 67.1 years vs. 63.0 years, p=0.06). GYN patients with BMs compared to non-GYN patients were more likely to have resection of BMs (48.5% vs. 25.6%, p=0.003), larger planned target volumes of all BMs (mean 23.6cc vs mean 15.2cc, p=0.02), and pre-SRS chemotherapy (72.7% vs. 49.6%, p=0.009). GYN patients were less likely to have whole brain radiation therapy prior to SRS (0 vs. 10.5%, p=0.049). GYN patients had worse OS compared to non-GYN patients (median 6.6 months (95% CI 3.3-12.4) vs. 10.0 months (95% CI 9.1-11.2), (HR 1.62 (95% CI 1.11-2.36), p=0.011)). Median FFICP for GYN patients was 9.5 months (95% CI 4.0-not reached) and for non-GYN patients was 8.7 months (95% CI 7.7-9.5). There was no difference in FFICP for GYN patients compared to non-GYN patients (HR 0.84 (95% CI 0.5-1.5), p=0.55). When comparing patients with BMs from endometrial cancer versus ovarian cancer, there was no difference in OS (p=0.13) or FFICP (p=0.58). These data may help guide treatment decisions and post-therapy surveillance in patients with BMs of GYN origin.