Initial treatment of melanoma brain metastases using gamma knife radiosurgery: an evaluation of efficacy and toxicity.

BACKGROUND: Melanoma is the primary malignancy that is most likely to metastasize to the brain. Because such an event carries an almost uniformly poor prognosis, the current study reviewed outcomes and identified associated prognostic indicators for 51 consecutive patients receiving gamma knife (GK) radiosurgery in the initial treatment of 188 intracranial melanoma metastases.

METHODS: Data were collected retrospectively from a single-center GK radiosurgery database and from primary patient medical records and radiographs.

RESULTS: At presentation, 71% of patients had multiple intracranial metastases, and extracranial metastases were present in 66% of patients. Thirty-two patients (63%) were initially treated with GK radiosurgery alone, whereas the remainder received GK radiosurgery in combination with surgery and/or whole-brain radiotherapy (WBRT). Overall median survival from time of GK radiosurgery was 26 weeks. Subgroup analysis revealed a median survival of 77 weeks for patients presenting with a single lesion, compared with 20 weeks for patients presenting with multiple lesions (P = 0.003). Patients in recursive partitioning analysis (RPA) Class I survived a median of 57 weeks, compared with a median survival of 20 weeks for patients in RPA Class II or III (P = 0.002). Although long-term imaging follow-up revealed that a majority of patients experienced distant brain metastases, multivariate analysis showed that distant metastases occurred significantly sooner in patients with extracranial metastases (P = 0.0004). Addition of initial WBRT had no significant effect on the time to development of new brain metastases (P = 0.13). Local control (crude) was observed in 81% of lesions initially treated with GK. Patients experienced improved or stable symptoms for a median of 37 weeks post-GK radiosurgery.

CONCLUSIONS: Survival analyses supported the use of GK radiosurgery in the initial treatment of patients with melanoma brain metastases, with best results occurring in patients presenting with a single lesion.