BACKGROUND: Breast cancer is the second most common source of brain metastasis. Stereotactic radiosurgery (SRS) can be an effective treatment for some patients with brain metastasis (BM). Necrosis is a common feature of many brain tumors, including BM; however, the influence of tumor necrosis on treatment efficacy of SRS in women with breast cancer metastatic to the brain is unknown. METHODS: A cohort of 147 women with breast cancer and BM treated consecutively with SRS over 10 years were studied. Of these, 80 (54.4%) had necrosis identified on pretreatment magnetic resonance images and 67 (46.4%) did not. Survival times were computed using the Kaplan-Meier method. Log-rank tests were used to compare groups with respect to survival times, Cox proportional hazards regression models were used to perform univariate and multivariate analyses, and chi-square and Fisher exact tests were used to compare clinicopathologic covariates. RESULTS: Neurological survival (NS) and survival after SRS were decreased in BM patients with necrosis at the time of SRS compared with patients without necrosis by 32% and 27%, respectively (NS median survival, 25 vs 17 months [log-rank test, P = .006]; SRS median survival, 15 vs 11 months [log-rank test, P = .045]). On multivariate analysis, HER2 amplification status and necrosis influenced NS and SRS after adjusting for standard clinical features, including BM number, size, and volume as well as Karnofsky performance status. CONCLUSION: Neuroimaging evidence of necrosis at the time of SRS significantly diminished the efficacy of therapy and was a potent prognostic marker.
BACKGROUND:Breast cancer is the second most common source of brain metastasis. Stereotactic radiosurgery (SRS) can be an effective treatment for some patients with brain metastasis (BM). Necrosis is a common feature of many brain tumors, including BM; however, the influence of tumor necrosis on treatment efficacy of SRS in women with breast cancer metastatic to the brain is unknown. METHODS: A cohort of 147 women with breast cancer and BM treated consecutively with SRS over 10 years were studied. Of these, 80 (54.4%) had necrosis identified on pretreatment magnetic resonance images and 67 (46.4%) did not. Survival times were computed using the Kaplan-Meier method. Log-rank tests were used to compare groups with respect to survival times, Cox proportional hazards regression models were used to perform univariate and multivariate analyses, and chi-square and Fisher exact tests were used to compare clinicopathologic covariates. RESULTS: Neurological survival (NS) and survival after SRS were decreased in BM patients with necrosis at the time of SRS compared with patients without necrosis by 32% and 27%, respectively (NS median survival, 25 vs 17 months [log-rank test, P = .006]; SRS median survival, 15 vs 11 months [log-rank test, P = .045]). On multivariate analysis, HER2 amplification status and necrosis influenced NS and SRS after adjusting for standard clinical features, including BM number, size, and volume as well as Karnofsky performance status. CONCLUSION: Neuroimaging evidence of necrosis at the time of SRS significantly diminished the efficacy of therapy and was a potent prognostic marker.