A comparison of two different radiation schedules for metastatic spinal cord compression considering a new prognostic factor

Background: Patients with metastatic spinal cord compression are often presented for emergency radiotherapy. The optimum radiotherapeutic regimen is still debated, studies comparing different radiation schedules on therapeutic outcome are scarce. This analysis compares the effect of two schedules on motor function considering three relevant prognostic factors (type of primary tumor, pre-treatment ambulatory status, time of developing motor deficits before radiotherapy). Patients and Methods: In this retrospective analysis, two radiation schedules, 30 Gy/10 fractions (n = 78) and 37.5 Gy/15 fractions (n = 75), applied due to motor deficits caused by metastatic spinal cord compression, were compared for post-treatment functional outcome and ambulatory status. Response and ambulatory status were evaluated directly, 3, 6 and 12 months after radiotherapy. For functional outcome a multivariate analysis including radiation schedule and the relevant prognostic factors was performed. Results: Between the two radiation schedules no significant difference was observed for post-treatment ambulatory rates (p values: 0.450-0.888) and for functional outcome (p values: 0.940-0.999). According to the multivariate analysis, the strongest predictors for functional outcome were the time of developing motor deficits before radiotherapy (p < 0.001) and the pre-treatment ambulatory status (p < 0.001), followed by the type of primary tumor (p = 0.058). For the radiation schedule a significant impact on functional outcome was not observed (p = 0.822). Conclusions: The two radiation schedules were comparable for functional outcome. The less time consuming schedule (30 Gy/10 fractions) can be recommended in metastatic spinal cord compression, as life expectancy is markedly reduced in the majority of these patients.