A matched-pair analysis comparing 5x4 Gy and 10x3 Gy for metastatic spinal cord compression (MSCC) in patients with favorable survival prognoses

Background: It is currently not possible to get an approval of our ethics committee for a randomized trial cmparing 5x4 Gy and 10x3 Gy for MSCC that includes patients with favorable survival prognoses. Therefore, this matched-pair study following strict matching criteria was perfomed instead. Methods: In this study, 142 receiving 5x4 Gy were retrospectively matched (1:1) to 142 patients receiving 10x3 Gy with respect to ten characteristics. These characteristics included age, gender, performance status, tumor type, involved vertebrae, other bone metastases, visceral metastases, interval between tumor diagnosis and MSCC, pre-RT ambulatory status, and time developing motor deficits. Results: On multivariate analysis, post-RT motor function was associated with performance status (p < 0.001), tumor type (p < 0.001), and time developing motor deficits (p < 0.001). RT was successful in 76% of patients receiving 5x4 Gy and 69% receiving 10x3 Gy (p = 0.14). Pre.RT ambulatory status showed a strong trend with respect to local control (LC) of MSCC in the multivariate analysis (p = 0.058). 1-year LC rates were 87% after 5x4 Gy and 93% after 10x3 Gy (p = 0.16). On multivariate analysis, survival (OS) was associated with performance score (p <0.001), visceral metastases (p < 0.001), and pre-RT ambulatory status (p = 0.004). 1-year OS rates were 68% after 5x4 Gy and 73% after 10x3 Gy (p = 0.64). Conclusions: In patients irradiated for MSCC who had favorable survival prognoses, post-RT motor function, LC and OS were not significantly different after 5x4 Gy and after 10x3 Gy.