Patients' Guide to Spinal Cancer

Understanding Metastatic Spine Cancer and Spinal Tumors

Metastatic cancer accounts for an estimated 70 percent of all spinal tumors

If your doctor says your spinal tumor is metastatic, it means your cancer began in a different area of your body and then spread to your back or neck. The spine is the third most common site for metastatic cancer. Metastatic spinal cancer can invade any part of the spine—the spinal vertebrae (bones), nerves, spinal cord and the cord’s protective membranes or sheaths call meninges (ie, dura mater, arachnoid mater, pia mater).
Illustration of spinal cord meninges labeledResearchers estimate that at least 30 percent and as high as 70 percent of people with metastatic cancer will experience spread of cancer to their spine. Spinal metastases tend to impact men slightly more than women, and metastases occur most often in adults age 40–65.

Metastatic cancer accounts for an estimated 70 percent of all spinal tumors, so cancer in your neck or back is much more likely to be metastatic rather than primary. Primary cancers are those that live in the site (eg, lung, breast) where they initially grew, in contrast to metastatic tumors that develop in one location and travel or spread to another.

This article focuses on metastatic spinal tumors; if you’d like to learn more about primary spinal bone cancers, please read our articles about chordoma, osteosarcoma, and Ewing's sarcoma.

What Are Metastatic Spinal Tumors?
The spine is a common target for metastatic cancer. Cancers that originate in the lung, breast, and gastrointestinal tract are the three most likely cancers to travel to the spine. Prostate, lymphoma, melanoma, and kidney are also common primary sources of metastatic spine cancer.

Metastatic spine tumors fit into three main groups:

  1. Intramedullary: Intramedullary tumors grow inside the spinal cord, most often in the cervical (neck) region, and they are rare—only five to 10 percent of all spinal tumors fall into this category.
  1. Intradural-extramedullary: Intradural-extramedullary tumors grow outside of the spinal cord, typically in the spinal cord’s arachnoid membrane, the nerve roots around the spinal cord, and at the base of the spinal canal.
  1. Epidural, or extradural, tumors: The majority of metastatic spine tumors fit into this category. These tumors grow in the bones of the spine—and when they travel from a different location in the body, they may be referred to as bone metastases.

More about bone metastasis
While cancer can spread to any bone in the body, the spine’s central location makes it the most common site for bone metastasis. A bone metastasis is bone that contains cancer that originated in a different area of the body.

Bone metastasis can affect the bones of the spine by interfering with the two main cell types responsible for maintaining healthy bones: osteoblasts and osteoclasts. Osteoclasts break down old bone, while osteoblasts build new bone. When these cells work in a balanced fashion, your bones stay strong.
Internal bone structure showing: osteocyte, osteoclast and osteoblastSometimes, bone metastasis in the spine causes osteoblasts to create too much bone, which can lead to a bone-stiffening condition known as sclerosis.

In other cases, bone metastasis can do the opposite by making the osteoclasts overwork, causing too much bone to be dissolved. This can result in weak bones, and increase the risk for spinal fracture.

Most bone metastases in the spine—70 percent—are found in the thoracic (mid-back) region, while 20 percent are in the lumbar (low back) area, and 10 percent are in the cervical (neck) spine.

What Causes Metastatic Spinal Tumors?
Scientists haven’t discovered any risk factors or causes for why cancer metastasizes to the spine in some people and others it does not. However, they do understand how these types of tumors develop.

Metastatic tumors form when cancerous cells leave the original (primary) tumor site through the bloodstream or lymph vessels, taking them to other areas of the body. While many of these cells die after leaving the primary tumor, some settle and thrive in other areas of the body and form new tumors. If one new tumor is formed, it’s called a metastasis; when two or more tumors develop, it’s referred to as metastases.

Updated on: 02/28/17
Continue Reading
Symptoms of Metastatic Spine Cancer and Spinal Tumor Diagnosis
Continue Reading:

Symptoms of Metastatic Spine Cancer and Spinal Tumor Diagnosis

Back or neck pain can be an early symptom of a metastatic cancerous spinal tumor. Many patients report the pain may worsen as their activity level increases and during nighttime hours.
Read More