Spinal Cord Cancer

 

Primary tumors of the spinal cord account for 15% of all central nervous system tumors, with 1/3 of the tumors located within the cord itself (intramedullary) and the remaining 2/3 outside the medullary covering of the cord fibers (extramedullary). These tumors are typically astrocytomas, ependymomas, and oligodendrogliomas.

Additionally, tumors can be located outside both the medulla and the dura (another lining of the spinal canal) but these are typically tumors that originated elsewhere (metastases) or primary tumors of the vertebral bodies (osteogenic sarcoma, multiple myeloma).

Patients typically present with focal pain, nerve root weakness, sensory deficit, or incontinence. When the weakness and/or incontinence is severe, it could indicate what is called a “cord compression”, which is diagnosed by MRI and is typically a medical emergency.

Standard workup for spinal tumors includes MRI of the spine, CSF cytology (“spinal tap”), and occasionally additional imaging of the chest and brain to rule out involvement of tumor elsewhere in the body.

Treatment for primary tumors is typically maximal safe resection followed by postoperative therapy with radiation to either the postoperative bed or to the entire craniospinal axis (this includes the brain and entire spinal cord and its lower nerve roots), depending on the type of tumor and the surgical margin status.

Sophisticated radiotherapy techniques are now frequently used for unresectable tumors, including intensity modulated radiation therapy with standard linear accelerators and stereotactic body radiotherapy with the next generation of accelerators. This precise mode of delivery allows radiation oncologists to maximize dose to the tumor while sparing the critical surrounding structures, primarily the spinal cord itself. Patients can be treated in a single fraction or in slightly smaller daily fractions (“hypofractionation”).

There is also emerging data showing a benefit of using stereotactic body radiotherapy for metastatic lesions, which would allow for patients to receive the benefit of radiation in a shorter period of time. It also gives hope to patients who have already received radiation to that area (“retreatment”).

Outcomes in treatment depend on whether the tumors are low grade or high grade. Slow growing, low-grade tumors have a 10-year overall survival of 40-90% while high-grade tumors have a median survival of 6 months to 2 years. Spinal sarcomas have a 4 year overall survival of 60-70%.