A validated score estimating ambulatory status following radiotherapy of elderly patients for metastatic spinal cord compression

Background: This study was performed to develop a validated score predicting ambulatory status after radiotherapy (RT) alone for metastatic spinal cord compression (MSCC) in elderly patients.Methods: 1,129 elderly patients (≥65 years) were assigned to the test (N = 565) or validation group (N = 564). In the test group, nine pre-treatment factors (age, gender, tumor type, number of involved vertebrae, pre-RT ambulatory status, other bone metastases, visceral metastases, interval cancer diagnosis to RT, time developing motor deficits) and fractionation regimen were investigated. Factors significantly associated with post-RT ambulatory status on multivariate analysis were included in the score. The score for each factor was determined by dividing the post-RT ambulatory rate at 1 month (%) by 10. The total score represented the sum of these scores.Results: In the multivariate analysis of the test group, age, primary tumor type, pre-RT ambulatory status, visceral metastases, and time developing motor deficits were significantly associated with post-RT ambulatory status. Total scores were 19 to 41 points. In the test group, post-RT ambulatory rates were 5% for 19-25 points, 35% for 26-30 points, 80% for 31-34 points, and 98% for 35-41 points (p < 0.001). 6-month survival rates were 11%, 21%, 59% and 76%, respectively. In the validation group, post-RT ambulatory rates were 4%, 33%, 77% and 98%, respectively (p < 0.001).Conclusions: Patients achieving 19-25 points had very poor functional outcomes and survival, and may receive single-fraction RT for pain relief. Selected patients with 26-34 points may benefit from additional surgery. Patients achieving ≥35 points achieved favorable results after RT alone.