Radiation therapy in metastatic spinal cord compression. A prospective analysis of 105 consecutive patients. One hundred thirty consecutive patients with metastatic spinal cord compression (MSCC) were entered in a therapeutic protocol in which radiation therapy (RT) played the main role. When MSCC is diagnosed by clinical-radiologic methods such as myelography with or without computed tomography (CT) or magnetic resonance imaging (MRI), steroids are given and RT treatment started within 24 hours. When diagnostic doubts exist or stabilization is necessary, surgery precedes RT. Chemohormonal potentially responsive tumors are also treated with chemotherapy or hormonal therapy. Twelve patients (9.2%) underwent surgery plus RT, and 118 (90.8%) received RT alone. Thirteen (11%) early death patients were not evaluable. The 105 evaluable cases that received RT alone were analyzed. Median follow-up was 15 months (range, 4 to 38 months). Response among patients with back pain was 80%. In cases with motor dysfunction, 48.6% improved, and in 33 of 105 patients (31.4%) without motor disability there was no deterioration. Forty percent of patients with autonomic dysfunction responded to RT. Median survival time was 7 months with a 36% probability of survival for 1 year. The median duration of improvement was 8 months. The most important prognostic factor was early diagnosis. Radiosensitivity of tumor was only important in paraparetic patients in predicting response to RT. Complete myelographic block significantly diminished response to RT. Vertebral collapse did not influence response or survival. 