Patients' Guide to Spinal Cancer

Chordoma Is the Most Common Malignant Primary Bone Cancer in the Adult Spine

Overview about chordoma, typical symptoms and diagnostic steps

Chordoma is a rare and slow-growing type of bone cancer that may develop in the skull base and/or at any level of the spinal column—cervical, thoracic, lumbar, sacral, or coccyx (tailbone). This article focuses on chordoma tumors that affect the bones in the spine.

Approximately 300 people in the United States are diagnosed with chordoma each year. The incidence is estimated to around 1 case per every million people in a year. This type of bone tumor represents about 3-percent of all bone cancers and about 20-percent of primary spinal tumors. Primary means that the tumor developed in the spine and has not spread to another place in the body. Cancerous tumors that spread to other organs are termed metastatic (eg, metastatic spinal cancer).

What Is a Chordoma?
Chordomas are the most common bone tumor found in the sacrum (located between your hips). In fact, approximately half of all chordomas develop in the sacrum. Nearly one-third develop at the base of the skull. Chordomas also can arise from the cervical (neck), thoracic (mid back) and/or lumbar (low back) spine.

lower back, lumbar spine, sacrum within the pelvic bonesChordomas are the most common bone tumor found in the sacrum (located between your hips).There are three types of chordoma:

  1. Conventional or classic
  2. Chondroid (least aggressive; may involve cartilage)
  3. Dedifferentiated (most aggressive; resembles sarcoma, a cancer affecting bone and soft tissues)

Dedifferentiated chordoma tumors are the most likely to metastasize (spread). Anywhere from 20- to 40-percent of spinal chordomas metastasize to other areas of the body, such as the lungs and/or liver.

Chordomas are found to develop in people of all ages, although spinal chordomas tend to occur later in adult life. Men develop this bone cancer at a greater rate than women.

What Causes Chordoma?
The great majority of chordomas seem to develop without reason or obvious cause. Scientists believe chordomas are connected to T gene changes, which can be both inherited and in people with no family history of the disease.

Here’s how the T gene is connected to chordoma: The T gene is instrumental in creating brachyury, a protein essential to spine growth in embryos. Brachyury helps develop a rod-like support structure called the notochord, which is a precursor to the spinal column. The notochord disappears and is replaced by the spine before birth, but some notochord cells may remain in the spine or skull. These cells may start to rapidly reproduce and attack the spinal bones, eventually resulting in a chordoma tumor.

Duplications and increased activity of the T gene creates excess brachyury protein, but researchers don’t fully understand how the overabundance of brachyury protein contributes to chordomas. Also, many people with chordoma don’t have any T gene mutations, so more work needs to be done to clearly understand this spinal cancer’s cause.

Symptoms of Spinal Chordoma
Pain and neurological symptoms, including numbness and/or weakness in the neck, back, arms, and/or legs are the most common symptoms of spinal chordoma.  However, many patients with sacral chordoma have very little to no symptoms at early stages of the disease except for local pain.  Depending on the location of the chordoma in the spine, the bone tumor may compress the spinal nerves or spinal cord. It can also compress on other organs on tissues outside of the spine such as the pharynx or the rectum.

Symptoms associated with a cervical chordoma:

  • Neck pain
  • Weakness or numbness in the arms
  • Hoarseness of voice
  • Difficulty swallowing
  • Headache
  • Double vision

Symptoms associated with a lumbar or sacral chordoma:

  • Low back pain or tail bone pain
  • Weakness and/or numbness in the legs
  • Loss of bladder and bowel control
  • A mass on the low back or tailbone that is tender to the touch.

Sacral bone tumors do not cause symptoms, and the presence of a lump is often the first sign of a sacral chordoma.

How Spinal Chordoma is Diagnosed
Your doctor may order x-rays, CT scans, bone scans, or MRI to identify the spinal tumor, and determine its size, location and other important characteristics. A biopsy is necessary to confirm if the tumor is chordoma.

Two bone biopsy methods:

  • During a needle biopsy, the doctor extracts a small sample of the chordoma tumor using a hollow needle. The procedure is typically performed with a local anesthetic (numbing agent), although some twilight sedation or general anesthesia may be necessary.
  • When a large tumor sample is needed, a surgical biopsy may be performed. Under general anesthesia, in a hospital or outpatient setting, samples of the tumor are taken during a surgical procedure.
  • Needle biopsy is generally preferred given it less invasive and better tolerated by patients. In addition, the site and tract of biopsy can be a source of spread or recurrence. It is often planned as part of the surgical margin when planning for a wide margin en bloc tumor excision. As a result, biopsy through the mouth or rectum should be avoided as it will require vital tissues to be sacrificed to achieve a wide margin excision. A midline or paramedian posterior approach is generally preferred, and the tract should be marked clearly to allow for biopsy tract excision during the tumor excision.

Conclusion
The diagnosis of chordoma includes a careful review of your medical history, and includes an in-depth physical and neurological examination. Together with the results of lab tests (eg, blood), imaging studies and biopsy findings, the doctor can confirm the diagnosis. The next step usually includes discussion among the members of your medical treatment team, which includes you. Together, a customized treatment plan is devised that includes management of your symptoms throughout the different stages of care.

Updated on: 02/14/18
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Spinal Cancer: What You Should Know

SpineUniverse spoke with Ali A. Baaj, MD, who answers questions about spinal cancer; what it is, who is at risk, and how spinal cancer is diagnosed and treated.
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