Understanding Metastatic Spinal Tumors

Etiology

Metastatic spinal tumors are neoplasms located in the vertebrae that are commonly associated with a wide range of primary cancers, from breast, lung, and prostate to sarcomas, carcinomas, and hematological diseases. Tumors are commonly classified according to their location, whether it be intradural (intramedullary or extramedullary) or extradural. Extradural lesions, those occurring outside of the dura mater of the spinal cord, account for 95% of spinal lesions, the vast majority of these originating from the vertebrae.1

Metastatic spinal tumors, depending on their location, can have debilitating consequences with significant impact on the activities of daily living. Patients living with such tumors may experience increasing pain with common transitions such as rising from a chair or lying in a resting position. These tumors can ultimately impinge on the spinal cord and nerve roots, leading to numbness and, potentially, paralysis in areas throughout the body. Metastatic spinal tumors can also weaken the structure of the vertebrae, leading to vertebral compression fractures, which often present with acute back pain.

Incidence

Metastatic disease in the skeleton occurs in up to 85% of late-stage patients with the three most common types of cancer – breast, prostate and lung 2 – with the spine being the most common site of occurrence. Acute among bone metastases is spinal meningioma, accounting for roughly 25% of all spinal tumors.3  Studies show that between 10% and 40% of all cancer patients will develop metastatic spinal tumors, with even higher rates in elderly patients.4 Several post-mortem studies have found metastatic spinal tumors in more than 30% of all patients who died as a result of cancer and cancer-related comorbidities.5,6

When metastatic spinal tumors are discovered, the metastatic disease is often found to be affecting multiple levels of the spine and causing tumor growth in each affected vertebrae.

With over 1.5 million new cancer cases diagnosed in the United States annually, metastatic spinal tumors are believed to affect over 150,000 patients every year.

Patient Quality of Life

Patients often present with acute back pain and, depending on the location of the metastatic spinal tumors, numbness in the legs, buttocks, and other areas. When the pain becomes overwhelming, systemic treatment of the primary cancer may be halted, due to risks associated with cumulative toxicity of therapies, in order to begin other palliative therapies with the aim of addressing the metastatic spinal tumors and its associated pain.

While most cancer treatments focus on the eradication of the neoplasm, the endpoints in treating painful metastatic spinal tumors are often maximum pain relief and minimum delay in treatment of the primary cancer.  Treatment regimens that can balance these two needs are attractive complements to current standards of care.

References

1.    Bartels R, van der Linden Y, and van der Graaf W. “Spinal Extradural Metastasis: Review of Current Treatment Options”, CA Cancer J Clin. 2008;58:245-259.
2.    Kurup AN and Callstrom MR. “Ablation of skeletal metastases: Current status”,.J VascInterv Radiol. 2010; 21:S242-S250.
3.    Arnautovic K and Arnautovic A. “Extramedullaryintradural spinal tumors: a review of modern diagnostic and treatment options and a report of a series”, Bosn J Basic Med Sci. 2009; 9 Suppl 1:40-45.
4.    Cardoso ER, Ashamalla H, Weng L, Mokhtar B, Ali S, Macedon M, and Guirguis A.. “Percutaneous tumor curettage and interstitial delivery of samarium-153 coupled with kyphoplasty for treatment of vertebral metastases”, J. Neurosurg Spine 2009;10:336-342.
5.    Wong DA, Fornasier VL, and MacNab I. “Spinal metastases: the obvious, the occult, and the impostors”, Spine. 1990; 15(1):1-4.
6.    Ortiz Gómez JA. “The incidence of vertebral body metastases”, IntOrthop. 1995; 19:309-311.


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