Stability of spinal bone metastases in breast cancer after radiotherapy: a retrospective analysis of 157 cases.

PURPOSE: This retrospective analysis was performed to evaluate osteolytic bone lesions of breast cancer in the thoracic and lumbar spine after radiotherapy (RT) in terms of stability using a validated scoring system. METHODS: The stability of 157 osteolytic metastases, treated from January 2000 to January 2012, in 115 patients with breast cancer was evaluated retrospectively using the Taneichi score. Predictive factors for stability were analyzed and survival rates were calculated. RESULTS: Eighty-five (54%) lesions were classified as unstable prior to RT. After 3 and 6 months, 109 (70%) and 124 (79%) lesions, respectively, were classified as stable. Thirty fractures were detected prior to RT, and after RT seven cases (4.5%) with pathologic fractures were found within 6 months. None of the examined predictive factors showed significant correlation with stability 6 months after RT. After a median follow-up of 16.7 months, Kaplan-Meier estimates revealed an overall survival of 83% after 5 years. CONCLUSION: The majority of patients showed an improved or unchanged stability of the involved vertebral bodies after 6 months. The patients showed only minor cancer-related morbidity during follow-up and reached comparably high survival rates.