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Ovarian cancer is the fifth most common cancer in women. Brain metastases (BM) occur in <2% of metastatic epithelial ovarian cancer (EOC) cases .The incidence of BM is increasing due to improvements in the primary therapeutic options and prolongation of survival. Whole brain radiotherapy (WBRT) and Stereotactic Radiosurgery (SRS) are used in conjunction with surgical resection of BM in addition to systemic chemotherapy and supportive care. Whilst the prognosis for patients with BM is overall poor, SRS has been shown to be an effective treatment option. We report on the treatment outcomes of patients with ovarian cancer BM treated with SRS at our institution.

Medical records were reviewed on patients who were referred for SRS for BM secondary to EOC between January 2015 and December 2020. We obtained patient data, tumour characteristics including histology, size, number, location of BM and presence of extra-cranial metastases. Treatment planning was done on iPlan software. SRS dosimetry on each patient was obtained and follow-up neuro-imaging that was done to evaluate treatment response was reviewed. The Kaplan-Meier method was used to estimate survival times for individual patients from the day SRS was completed to the date of last follow up or death. 

A total of 18 patients were referred. Two patients received WBRT and were excluded. Sixteen patients were included in the study all of whom had a papillary serous adenocarcinoma. Nine patients had extra-cranial metastases at the time of referral. The median age was 60 years (range 42 to 73). A total number of 19 metastases were treated. Nine were in-situ and 10 post-operative.  The median GTV in cc for the in-situ lesions was 7.0 cc and that of the post-operative cavity was 7.7 cc. Seven metastases were treated with a single fraction, 7 with 3 fractions and 5 with 5 fractions.The median single fraction dose used was 18 Gray (range 16 to 24 Gy).The median 3 fraction dose was 27 Gy (range 24 to 27 Gy). The median normal tissue V12 for the single fraction treatment was 4.2 cc.  The median normal tissue V18 and V24 for the three fraction treatments was 15.2 cc and 9.8 cc respectively. The most common toxicities documented were effect on memory and fatigue. Five patients had intracranial disease recurrence with metastases elsewhere in the brain. Progression free survival (PFS) was 6.9 months. Thirteen patients (81%) out of the 16 died. An estimated 47% (95% CI: 22% to 72%) and 39% (95% CI: 14% to 65%) were surviving at 1 and 2 years respectively. Median overall survival (OS) was 10.6 months.

The outcome of patients with brain metastases from EOC remains very poor. Our retrospective analysis has showed that SRS is an effective treatment option and results in comparable OS rates as per reported literature. Future studies should focus on the effective integration of SRS into a multimodal treatment approach to obtain better treatment outcomes for patients