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Malignant Melanoma is the third most common cause of brain metastases behind lung and breast cancer. Between 10% and 40% of patients are diagnosed with brain metastases during the course of their disease. The median survival in these patients is 4–5 months, with intracranial disease progression being the direct cause of death in 20%–54%. The median overall survival (OS) ranged between 8–10 months even in patients who received local treatments. The main treatment modalities are surgery, whole-brain radiotherapy (WBRT) and stereotactic radiotherapy (SRS). WBRT is associated with increased neurotoxicity and decreased quality of life. Stereotactic radiosurgery (SRS) is an increasingly used treatment with good effect. There is additional benefit gained when combined with immune checkpoint inhibitors. We present a retrospective review of patients with malignant melanoma metastasis to brain treated at our institution with SRS.

Patients who received SRS for malignant melanoma metastasis between August 2013 and November 2016 were identified. We obtained patient data including age, gender, toxicities and tumour characteristics including BRAF status. Image fusion and treatment planning were done on iPlan radiotherapy planning software. Follow-up imaging was reviewed to document treatment response. OS was calculated from the day SRS was completed to the date of last follow-up or death. The Kaplan-Meier method was used to estimate survival times for individual patients.

Twenty-nine patients were identified, fifteen female and fourteen male. The median age was 54 years. Six Patients had prior WBRT. Sixty-one metastasis were treated, with fifty-one treated in a single fraction, four treated with three fractions and six treated with five fractions. Eleven patients had BRAF mutation, twelve were wild type and six were unknown. Ten patients received concurrent systemic treatment. The median single fraction dose used was 20 Gray (range 16 – 24 Gy). The most common toxicity documented was effect on memory, hair loss and fatigue. The median OS was 8.1 months (95% CI: 0.4 – 15.8 months). Eight patients (28%) died within 3 months of their treatment. Three patients (10%) were alive more than 4 years post completion of SRS. The OS in BRAF mutated patients was 11.5 months (95% CI: 3 – 20 months). In those who received concurrent systemic treatment the OS was 23.8 months (95% CI: 0 – 69.7 months) compared to 4.4 months (95% CI: 0 - 12.7 months) in those who did not receive concurrent systemic treatment.

Stereotactic radiosurgery for brain metastases from Melanoma has been shown to prolong OS when compared to WBRT when used a stand-alone treatment modality or in combination with immunotherapy. Whilst our retrospective analysis has showed that SRS is an effective treatment option and results in comparable OS rates as per reported literature, further multicentre randomized control trials are required to further evaluate the effectiveness of SRS in this patient cohort.