Outcomes and prognostic factors for surgically treated patients with breast cancer spine metastases

PURPOSE: The aim of this study is to provide some useful insights into the treatments, outcomes, and prognostic factors of patients with breast cancer spine metastases (BCSM). METHODS: We report a retrospective case series analyzing 87 patients with BCSM who underwent surgical interventions. Independent prognostic factors for SMFS and OS were extracted using univariate and multivariate analyses, the Kaplan–Meier method and the Cox proportional hazards model. RESULTS: The mean time between primary diagnoses and spinal metastases was 46.8 (median 41, range 0–147 months) months. The analysis showed that lymph node metastasis (p = 0.043, HR 10.498, 95%CI 1.074–102.588) and estrogen receptor (ER) status (p = 0.004, HR 0.368, 95%CI 0.189–0.721) can significantly affect SMFS. Furthermore, visceral metastasis (p = 0.042, HR 2.383, 95%CI 1.032–5.501), multiple metastases (p = 0.035, HR 2.538, 95%CI 1.066–6.048) and post-op chemotherapy (p = 0.003, HR 0.312, 95%CI 0.144–0.675) have significant effects on OS. Lastly, patients identified as Luminal A subtype have longer OS. CONCLUSIONS: Lymph node metastases and ER status are independent risk factors in predicting BCSM. Moreover, visceral metastasis, multiple metastases of the spine and post-op chemotherapy are independent prognostic factors. Luminal subtypes have higher rate, but late onset of spine metastases and prolonged survival.