Clinical usefulness of an algorithm for the early diagnosis of spinal metastatic disease.

We have previously reported an algorithm that invokes several imaging modalities in the early detection of metastatic and benign disease of the spine in patients with cancer (J Clin Oncol 4:576, 1986). The development of new lesions (shown by Tc99m bone scans) in cancer patients with normal neurological examinations is further evaluated with plain radiographs, spinal computed tomography (CT), and CT myelography (CT-M). Of 60 patients in the original study, 28% were diagnosed as having only benign disease and the remainder had spinal metastases. Thecal sac impingement was seen in 47% of patients with metastatic disease and disruption of the posterior vertebral cortex was noted in all patients with epidural compression. We now report the 2-year follow-up of 55 of these patients. Without treatment, the 17 patients diagnosed with benign disease have shown no evidence of local failure in the spine and median survival is greater than 27 months. Thirty-eight patients diagnosed with spinal metastases had a median survival time of 16.9 months. Radiation therapy directed by CT-M findings provided pain relief in 78% of patients with back pain and metastatic disease. No patient, including 19 with thecal sac impingement, developed clinical myelopathy. These results demonstrate the usefulness of an imaging algorithm for the early identification and distinction of spinal metastatic disease and benign disease in patients with cancer.