Role of the overall treatment time of radiotherapy with 10 × 3 Gy for outcomes in patients with metastatic spinal cord compression

Introduction: Radiotherapy alone still is the most commonly delivered treatment modality for metastatic spinal cord compression (MSCC). MSCC is an emergency situation, which requires treatment as soon as possible. When radiotherapy is performed with the most commonly used approach 10 × 3 Gy (30 Gy in 10 fractions) over 2 weeks, the question has been asked whether an overall treatment time (OTT) of 14–15 days including two weekends without irradiation leads to worse outcomes than OTT of 12 days (beginning of radiotherapy on a Monday resulting in only one weekend break)?. Methods: A total of 412 patients with MSCC were included in this retrospective study. Ninety-two patients receiving 10 × 3 Gy over 12 days were compared to 320 patients with an OTT of 14–15 days. Ten additional factors were investigated. Results: On multivariate analysis, functional outcome was associated with tumour type (P < 0.001), time developing motor deficits (P < 0.001), ambulatory status (P = 0.018) and performance score (P < 0.001); OTT had no significant impact (P = 0.40). On univariate analysis of local control of MSCC (freedom from recurrence in irradiated spinal parts), no factor was significant including OTT (P = 0.66). On multivariate analysis, visceral metastases (P < 0.001), tumour type (P < 0.001), time developing motor deficits (P < 0.001), ambulatory status (P < 0.001) and performance score (P < 0.001) were associated with survival, OTT not even on univariate analysis (P = 0.55). Conclusions: Since an OTT of 14–15 days had no negative impact on outcomes compared to 12 days, compensation in form of an additional radiation fraction or continuation of radiotherapy during weekends is not required, if radiotherapy cannot be started on a Monday.