Outcomes and predictors of improved survival after gamma knife radiosurgery for metastatic brain tumors originated from breast carcinoma.

Gamma knife radiosurgery (GKRS) has emerged as a possible treatment option for metastasis brain tumor (MBTs) originated from breast cancer. However, the intermediate or long-term outcome of GKRS on MBTs originated from breast carcinoma is not well defined. The outcome of GKRS on MBTs derived from breast carcinoma was reviewed in our institution's case series. We performed a retrospective review (2000-2013) of 50 patients with MBTs originated from breast cancer who received GKRS. Out of 50 patients, 11 patients had recurrent tumors after microsurgical resection and the other 39 patients received GKRS alone. The study population was followed clinically and radiographically after GKRS treatment. GKRS on MBTs metastasized from breast cancer showed significant variations in tumor growth control (decreased in 14 (31.9 %) patients, arrested growth in 17 (38.6 %) patients, and progressed tumor in 13 (29.5 %) patients). The overall median survival in this case series was 33 months. In our case series, overall survival rate after 5 years was 20 %, whereas progression-free survival rate after 5 years was 30 %. The prognostic factors for improving survival in the patients with MBTs from breast cancer were recursive partitioning analysis (RPA) class I (p = 0.014), age ≤65 years (p = 0.025), controlled primary tumor (p = 0.04), and single number of MBTs (p = 0.022). Recent follow-up revealed that GKRS offers good overall survival period in both new and recurrent patients with MBTs originated from breast carcinoma. Thus, GKRS is a therapeutic option for new and recurrent patients with MBTs derived from breast cancer.