Prognostic factors predicting functional outcomes, recurrence-free survival, and overall survival after radiotherapy for metastatic spinal cord compression in breast cancer patients.

Abstract

To identify significant prognostic factors after irradiation of metastatic spinal cord compression (MSCC) in 335 breast cancer patients. The potential prognostic factors investigated included involved vertebra, other bone metastases, visceral metastases, performance status, pretreatment ambulatory status, time until motor deficits developed before RT, radiation schedule (shorter-course RT [one fraction of 8 Gy/five fractions of 4 Gy] vs. longer-course RT [10 fractions of 3 Gy/15 fractions of 2.5 Gy/20 fractions of 2 Gy), and the response to RT. On multivariate analysis, better functional outcome was associated with slower development of motor deficits (p <0.001) and being ambulatory before RT (p <0.001). The overall recurrence rate of MSCC was greater if other bone metastases were present (p <0.001) and if shorter-course RT was used (p <0.001). In-field recurrences alone were more frequent after shorter-course RT (p = 0.008). Survival was negatively affected by the presence of visceral metastases (p <0.001), deterioration of motor function after RT (p <0.001), reduced performance status (p <0.001), and the rapid development of motor deficits (p = 0.044). Outcomes and survival after RT for MSCC in breast cancer patients are associated with several prognostic factors. Patients with poor expected survival may be treated with shorter-course RT to keep the overall treatment time short. If survival is expected to be relatively favorable, longer-course RT appears preferable, because it is associated with fewer MSCC recurrences.