A non-randomized prospective trial in which radiotherapy (RT) alone played the major role in the treatment of metastatic spinal cord compression (MSCC) is reported. Diagnosis was formulated on myelography and/or myelography plus computed thomography (CT). Of 51 cases treated, 48 are evaluable. The therapy consisted of radiation alone (42 cases) or decompressive laminectomy followed by radiotherapy (6 cases). Surgery was performed when the site of the primary tumor was unknown. The group of patients who received radiotherapy alone (42 of 48 evaluable cases) are analysed in this report. Medium to high doses of steroids were administered to all patients depending on the gravity of the case. Patients with chemo- or hormone-responsive primary tumors also received chemotherapy and/or hormone therapy. Pain relief, assessed by comparing use of narcotics and minor analgesics before and after treatment, was achieved in 54% cases (confidence limits, CL = 38-69%). In 36% (CL = 22-51%) of patients back pain diminished to the point when only milder analgesics were necessary (partial remission). Motor performance, based on patients' ability to walk, improved in 48% cases (CL = 31-65%). The 19 patients who were ambulatory before RT, did not deteriorate after treatment. Sphincter function, evaluated by patient's need for indwelling catheter, improved in 3 of 7 automatic dysfunction cases. It was found that early diagnosis was more important than primary tumor type for predicting a good was found that early diagnosis was more important than primary tumor type for predicting a good prognosis. In fact, all ambulating patients responded to treatment independent of the radiosensitivity of the tumor histology.(ABSTRACT TRUNCATED AT 250 WORDS)