Stereotactic radiosurgical treatment of cerebral metastases arising from breast cancer

Objective: This study was undertaken to evaluate the outcome of patients undergoing stercotactic radiosurgery (SRS) as primary or salvage treatment of brain metastases arising from breast cancer. Materials and Methods: Between July 2000 and September 2005, the medical records of 49 breast cancer patients who underwent SRS for 84 brain metastases were reviewed retrospectively. Thirty-four patients received SRS as primary brain metastasis treatment and 15 patients received SRS as salvage treatment of brain metastasis recurrence following prior whole-brain radiation therapy. The Kaplan-Meier method, univariate comparisons with log-rank test, and multivariate analysis were performed. Results: Median follow-up was 12 months (range, 5-50 months) and median survival was 19 months for all patients. The 1- and 2-year overall survival (OS) rates were 60%, 56%, and 55%, 23% for initial SRS alone and SRS salvage groups, respectively (P = 0.99). A multivariate analysis showed that a high KPS score (KPS >= 90 vs. <90; P = 0.02), a higher SIR value (SIR >= 6 vs. < 6; P = 0.001), postmenopausal status (P = 0.003), and positive estrogen receptor status (P = 0.04) were predictive of better survival. The land 2-year local control rates were 79%, 49%, and 77%, 46% for SRS alone and SRS salvage group, respectively. Conclusion: SRS can be used as primary treatment of brain metasTases or salvage of recurrences after whole-brain radiation therapy to achieve good local control on the order of close to 80% at I year. The median survival of brain metastasis patients with breast cancer of 19 months appears favorable compared with the general brain metastasis population.