RDTA-10 OVARIAN CLEAR CELL CARCINOMA BRAIN METASTASES: CASE SERIES AND SYSTEMATIC REVIEW

Abstract Ovarian clear cell carcinoma (OCCC) is an aggressive histology which is often resistant to conventional chemotherapy. Brain metastases (BM) from OCCC are exceedingly rare, with no prior documented outcomes of stereotactic radiosurgery (SRS) for OCCC BM. A retrospective review was performed of cases of histopathologically-confirmed OCCC treated with SRS at our institution between 2003 and 2024, identifying 2 cases with a total of 10 BM. Age at OCCC diagnosis was 53 and 73 years, with both patients developing BM within 2 years. Both patients additionally presented with extracranial metastases, with sites including the peritoneum and lungs, and received chemotherapy prior to SRS. Median BM volume and diameter at baseline were 0.16 cm3 and 7.9 mm, respectively. Patients underwent SRS to a median prescribed dose of either 25 or 24 Gy, with both treatments delivered to an isodose line of 72%. A single fraction was used for 60% of BM, while the remaining 40% of lesions were treated with 5 fractions. Overall survival from time of SRS was 3.75 and 4.0 months. Treated lesions had a median size reduction of 38.1% at 3-month follow-up, with none of these lesions demonstrating local progression during the follow-up period. Additionally, we performed a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to contextualize our results. Eight articles containing a total of 9 patients reported specific outcomes for OCCC BM. Surgical resection was the most common treatment, followed by whole-brain radiotherapy, with a median OS of 2.5 months (range: 1-7 months). Only 1 study was published in a neurosurgical journal. Our results suggest SRS may be effective for management of OCCC BM, with favorable local control and overall survival. Our systematic review highlights variability in treatment outcomes, as well as existing gaps in neurosurgical investigation of this histology.