Evaluation of functional outcome and local control after radiotherapy for metastatic spinal cord compression in patients with prostate cancer

Purpose: Patients with prostate cancer with metastatic spinal cord compression have better survival prognosis than other patients with MSCC and may live long enough to develop a local recurrence of MSCC. This study investigates prognostic factors and radiation schedules for functional outcome and local control of MSCC after radiotherapy in patients with prostate cancer. Materials and Methods: A total of 281 patients irradiated between January 1992 and December 2003 were included. Potential prognostic factors were investigated including age, performance status, number of involved vertebra, pretreatment ambulatory status, time of developing motor deficits before RT and radiation schedule - short course RT (1×8/5×4 Gy) vs long course RT (10×3/15×2.5/20×2 Gy). Results: Overall response to RT was 86% (33% improvement of motor function, 53% no further progression). Of the nonambulatory patients 33% regained the ability to walk. On multivariate analysis functional outcome was significantly affected by the time of developing motor deficits before RT (more than 14 days better than 8 to 14 days and 1 to 7 days, p <0.001) and number of involved vertebrae (1 to 2 better than 3 or more, p = 0.013), but not by the radiation schedule (p = 0.859). The 2-year local control of MSCC was 84% depending on the radiation schedule (better after long course RT, p = 0.001). Conclusions: Functional outcome after RT was significantly influenced by the time of developing motor deficits before RT and number of involved vertebra. Local control was significantly better after application of long course RT. Patients with a poor expected survival could be treated with short course RT, because a short treatment time means less discomfort for the patient. For patients with good survival prognosis, long course RT should be applied to achieve better local control.