Background: The proportion of metastatic renal cancer (mRC) patients with intracranial involvement is 8%, and 2% develop brain secondaries exclusively [1]. Although renal cancer is generally regarded as relatively radioresistant, studies have shown patients treated with stereotactic radiosurgery (SRS) demonstrate a local progression free survival (PFS) rate of 79-84% at 1 year and median overall survival (OS) of 9.6 – 13.9 months [2,3]. We evaluate the outcomes of patients with mRC who have received SRS to intracranial metastases at two tertiary centres in the North West of England. Methods: Patients who received SRS from January 2017 to July 2019 at Royal Preston Hospital, and from May 2016 to March 2021 at the Christie were retrospectively identified from the database of the respective hospitals. Clinical records were used to obtain demographics, therapies received and follow up data. Results: A total of 41 patients were identified. 31 patients (76%) were male and the average age at treatment was 59.6 years. 5 patients received treatment on >1 occasion, but only the first episode was considered for analysis. 80.4% had a performance status of 0-1 and most patients had clear cell histology. 19 patients (46.3%) had lesions treated bilaterally. The median follow up time was 11 months. Prescribed doses ranged between 18Gy to 30Gy in 1-5 fractions. 11 patients (26.8%) progressed during the follow up period, with a median time to progression of 5 months. The longest time to progression was 17 months, in a patient who received Nivolumab following SRS. 28 patients (68.3%) died during the follow up period with a median time to death of 9.1 months. Median OS was 11 months, with 19 out of the 28 patients (67.9%) dying within the first year. The 1 year survival rate was 52.6% and 2 year survival rate was 16.2%. A range of systemic agents were used pre and post SRS including immunotherapy. 6 patients (23%) commenced immunotherapy following SRS (nivolumab +/- ipilimumab), with OS ranging from 6 – 49 months (average 25.5 months). Conclusions: We found that outcomes in this cohort of patients treated with SRS were comparable to previous findings. A subgroup who commenced Nivolumab following SRS demonstrated an average survival of over 2 years.

References [1] Bianchi M et al. Distribution of metastatic sites in renal cell carcinoma: a population-based analysis. Ann Oncol 2012;23:973–80. [2] Lesueur P et al. Radiosurgery or hypofractionated stereotactic radiotherapy for brain metastases from radioresistant primaries (melanoma and renal cancer). Radiat Oncol 2018;13:138. [3] Ippen FM et al. Stereotactic Radiosurgery for Renal Cancer Brain Metastasis: Prognostic Factors and the Role of Whole-Brain Radiation and Surgical Resection. J Oncol 2015;2015:1–13.