Predictors of survival, neurologic death, local failure, and distant failure after gamma knife radiosurgery for melanoma brain metastases

Objective This study sought to assess clinical outcomes in patients receiving gamma knife radiosurgery (GK) for treatment of brain metastases from melanoma and evaluate for potential predictive factors.

Methods We reviewed 188 GK procedures in 129 consecutive patients that were treated for brain metastases from melanoma. The population consisted of 84 males and 45 females with a median age of 57 years. Fifty-five patients (43%) had a single metastasis. Seventy-one patients (55%) received chemotherapy, 58 patients (45%) received biologic agents, and 36 patients (28%) received prior whole brain radiation therapy (WBRT). The median marginal dose was 18.8 Gy (range 12 to 24 Gy).

Results Actuarial survival was 52%, 26%, and 13% at 6, 12, and 24 months, respectively. The median survival time was 6.7 months. Local tumor control was 95%, 81% 53% at 6, 12, and 24 months, respectively. The median time to LBF was 25.2 months. Freedom from distant brain failure was 40%, 29%, and 10% at 6, 12, and 24 months, and the median time to DBF was 4.6 months. At the time of data analysis, 108 patients (84%) had died. Fifty-eight patients (52%) died from neurologic death. The median time to neurologic death from GK treatment was 7.9 months. Multivariate analysis revealed that hemorrhage of metastases prior to GK (P =.02) and LBF (P =.03) were the dominant predictors of neurologic death.

Conclusions GK achieves excellent local control and may improve outcomes as a component of a multidisciplinary treatment strategy. Distant brain failure and neurologic demise remain problematic and prospective trials are necessary.