Outcome after radiotherapy alone for metastatic spinal cord compression in patients with oligometastases

Purpose To investigate outcome and prognosis of metastatic spinal cord compression (MSCC) patients with oligometastatic disease treated with radiotherapy alone. Patients and Methods Oligometastatic disease was defined as involvement of three or fewer vertebrae and lack of other bone or visceral metastases. Five hundred twenty-one patients with oligometastatic disease and MSCC were evaluated for functional outcome, ambulatory status, local control of MSCC, and survival. Furthermore, seven potential prognostic factors were investigated. Results Motor function improved in 40% (n = 207), remained stable in 54% (n = 279), and deteriorated in 7% (n = 35) of patients. Fifty-eight (54%) of 107 nonambulatory patients became ambulatory, and 388 (94%) of 414 ambulatory patients remained ambulatory. Improved functional outcome was significantly associated with tumor type and slower development of motor deficits (>14 days). Local control at 1, 2, and 3 years was 92%, 88%, and 78%, respectively. Improved local control was significantly associated with long-course radiotherapy. Survival at 1, 2, and 3 years was 71%, 58%, and 50%, respectively. Better survival was significantly associated with tumor type, ambulatory status, slower development of motor deficits, and long-course radiotherapy. Patients who developed motor deficits slowly (onset >14 days before initiating treatment) were further analyzed. In this subgroup, the best results were observed for myeloma/lymphoma and breast cancer patients. No patient had progression of motor deficits. One hundred percent (myeloma/lymphoma) and 99% (breast cancer) of patients were ambulatory after radiotherapy. One-year local control was 100% and 98%, 1-year survival was 94% and 89%. Conclusion Given the limitations of a retrospective review, improved outcome of patients with oligometastatic MSCC was associated with myeloma/lymphoma and breast cancer, slower development of motor deficits, and a more prolonged course of radiation.