Spinal Metastases From Gastrointestinal Malignancies

Abstract

Among 965,000 new patients with cancer occurring yearly in the United States, bone metastases will eventually develop in 30 to 70% (1). The most common site of metastases is the spine occurring in 50 to 70% of those with bone metastases (1). In adults, malignant bone tumors arise most frequently from extraosseous epithelial primaries, whereas children usually have primaries from within bone (2). Primaries most commonly associated with bone metastases are breast, prostate, lung, kidney, and thyroid carcinoma (1,3). Pain occurs in some, but not all, bone metastases as 33 to 50% of patients with skeletal metastases do not have pain (4). The experience of pain is not particular to gender or primary tumor-related, nor is it predictable based on radiological appearance. The primary site of malignancy remains unidentified in 10% of patients with skeletal and spinal metastases. In most series of bone and spinal metastases, gastrointestinal primaries make up a similar percentage of those with unknown primaries (3). The distribution of metastases within the spine follows the same pattern regardless of the primary site with few exceptions (3). Spinal cord compression is the most feared complication of spinal metastases and the distribution of metastases within the spine does not correlate with the same risk of cord compression. The thoracic spine is most vulnerable.