Background: This study was performed to identify new significant prognostic factors in breast cancer patients irradiated for metastatic spinal cord compression (MSCC).
Patients and methods: The data of 504 patients with breast cancer patients with MSCC were retrospectively analyzed with respect to posttreatment motor function, local control of MSCC, and survival. The investigated potential prognostic factors included age, Eastern Cooperative Oncology Group (ECOG) performance score, number of involved vertebrae, other bone metastases, visceral metastases, pretreatment ambulatory status, interval from cancer diagnosis to radiotherapy of MSCC, time developing motor deficits before radiotherapy, and the radiation schedule.
Results: On multivariate analysis, better functional outcome was associated with ambulatory status prior to RT (estimate - 1.29, p < 0.001), no visceral metastases (estimate - 0.52, p = 0.020), and slower development of motor deficits (estimate + 2.47, p < 0.001). Improved local control was significantly associated with no other bone metastases (risk ratio (RR) 4.33, 95% confidence interval (CI) 1.36-14.02, p = 0.013) and no visceral metastases (RR 3.02, 95% CI 1.42-6.40, p = 0.005). Improved survival was significantly associated with involvement of only 1-2 vertebrae (RR 1.27, 95% CI 1.01-1.60, p = 0.044), ambulatory status before radiotherapy (RR 1.75, 95% CI 1.23-2.50, p = 0.002), no other bone metastases (RR 1.93, 95% CI 1.18-3.13, p = 0.009), no visceral metastases (RR 7.60, 95% CI 5.39-10.84, p < 0.001), and time developing motor deficits before radiotherapy (RR 1.55, 95% CI 1.30-1.86, p < 0.001).
Conclusion: Several new independent prognostic factors were identified for treatment outcomes. These prognostic factors should be considered in future trials and may be used to develop prognostic scores for breast cancer patients with MSCC.