BACKGROUND.
Although multiple spinal epidural metastases (MEMs) commonly occur in cancer patients, their clinical significance remains uncertain. The authors attempted to ascertain the incidence of MEMs and their association with the completeness of spinal imaging by magnetic resonance (MR) scanning versus myelography to determine how often they are missed because of incomplete spinal imaging and to assess their prognostic and treatment implications.
METHODS. A review of 337 epidural spinal cord compression (ESCC) cases seen at
the Mayo Clinic between 1985 and 1993 was conducted.
RESULTS.
ESCC patients undergoing myelography only were significantly more likely to undergo complete spinal imaging (CSI)than patients undergoing either MR scan only or both imaging modalities (P Ο½ 0.0001). MEMs were detected in 32% of patients undergoing CSI and 18% of patients with incomplete spinal imaging (P Ο 0.02). Failure to image the cervical spine in patients with symptomatic thoracic or lumbar epidural lesions would have missed secondary epidural lesions in only 1% of patients; however, this figure increased to 21% for failure to image either the thoracic or lumbosacral spine when symptomatic disease was located elsewhere. Radiation oncologists included secondary epidural deposits in treatment ports in 93% of MEM cases. In a multivariate model, the presence of MEMs was an independent prognostic factor for poorer survival.
CONCLUSION.
The incidence of MEMs in patients with ESCC is approximately 30%, and their presence frequently alters treatment plans. It appears safe to forgo cervical spine MR scanning in patients with radiographically verified thoracic or lumbar ESCC; however, careful imaging of the thoracic and lumbar spine should be considered in all ESCC patients to detect MEMs.