Spinal Cord Compression
Compression of the spinal cord by a mass or tumor can cause decreased strength or sensation, and lead to pain, permanent paralysis, incontinence and even death. Metastatic malignant tumors are the major causes of spinal cord compression (SCC). Metastatic tumors from any primary site can produce SCC. Prostate cancer, breast cancer, and lung cancer are among the most common ones and each account for about 15% to 20% of cases. Renal cell carcinoma, non-Hodgkin's lymphoma, and plasmacytoma or multiple myeloma are less common and each accounts for 5% to 10% of all cases (Journal of Neurosurgery 1983 Jul;59(1):111-8). SCC can also be caused by non-cancerous condition, such as trauma, and infection. The remainder of this document will refer exclusively to cancer-induced SCC.
The incidence of SCC is not precisely known since some cancer patients may have asymptomatic or unrecognized SCC. Some earlier autopsy studies suggested that approximately 5% of all cancer patients died with SCC (Neurology 1959 9:91). The true incidence could be higher with more advanced imaging techniques and more aggressive work up in patients with advanced stage cancers.
The goal of therapy for SCC include pain control, avoidance of complications, preserving or improving neurologic functions or reversing impaired neurologic functions. High dose corticosteroid therapy is generally considered to be part of the standard regimen for SCC (Journal of Clinical Oncology 1998 Apr;16(4):1613-24). It remains uncertain if patients with less severe disease need steroid therapy. The optimal dosage of steroids is also unknown.
For most patients with cancer-induced SCC, radiation therapy is the definitive treatment of choice. Different dose-fractionation regimens have been used clinically, from 3000 cGy in 10 fractions to 1600 cGy in two fraction (International Journal of Radiation Oncology Biology Physics 1997 Jul 15; 38(5): 1037-44). Radiation therapy leads to resolution of back pain in most patients. Approximately one-third of patients who are nonambulatory because of paraparesis regain the ability to walk with treatment (Acta Neurochir (Wien) 1990;107(1-2):37-43).
Posterior decompression of SCC via laminectomy used to be the initial approach to the patients with SCC. Some small randomized studies demonstrated no difference in outcome between patients undergoing laminectomy followed by radiotherapy versus radiotherapy alone (Journal of Neurosurgery 1980 Dec;53(6):741-8). However, when SCC is caused by mechanical compression of cord by the collapsed vertebral body, laminectomy remains the preferred approach.
Bisphosphonates such as pamidronate can also be used in reducing pathologic fractures and bone pain in patients with multiple myeloma or breast cancer induced SCC (Journal of Clinical Oncology 1998 Jun; 16(6): 2038-44).
Finally, in some tumors known to be highly chemoresponsive, chemotherapy alone or in combination with other modalities may be advocated.