Chordoma

Definition

Chordomas are rare tumors of the central nervous system (brain and spinal cord).

Description

Chordomas are slow-growing tumors that invade bone and tissue surrounding the spinal column. They rarely spread to other parts of the body, but they can cause considerable damage or death because they destroy bone and soft tissue and often grow along the roots of nerves, putting pressure on the nerves and disrupting their function.

Chordomas appear at the base of the skull about 60% of the time and in the sacrum, located at the base of the spine, about 30% of the time. The other 10% of chordomas can occur anywhere else along the spinal column.

Demographics

Chordomas are very rare, accounting for between 1-4% of tumors of the brain and spinal column. Chordomas that occur at the base of the skull are most common in adults between 30 and 40 years of age. Those tumors that arise at the sacrum, located at the base of the spine, most commonly appear in older adults between the ages of 50 and 70. Chordomas are about twice as common in men as they are in women.

Causes and symptoms

During the fourth through sixth week of fetal development, a group of cells come together to form a structure called the notochord. The notochord defines the vertical mid-line of the body, and the spinal column develops around it. Normally, as development progresses, the noto-chord degenerates and disappears, except for small bits that become part of the disks between the spinal vertebrae. Chordomas are believed to develop from pieces of noto-chord that, for some reason, do not break down as they should. Over many years, these harmless bits of notochord transform and become malignant, forming chordomas.

Symptoms of chordoma depend on where the tumor is located. They are often vague and similar to symptoms of other tumors or even other conditions. Tumors located at the base of the skull may cause headaches, difficulty swallowing, or seizures depending on how much they have invaded the bones of the skull. Tumors located on the sacrum can cause general low back pain or difficulty with bowel and bladder control.

Diagnosis

Diagnosis has two parts: first, determining that the patient has a central nervous system tumor and where it is located, and second, determining what type of tumor it is. It is not easy to diagnose either of these.

A battery of tests is used to diagnose chordomas. A basic neurological examination tests the patient's reflexes, vision, hearing, senses of touch and smell, mental acuity, orientation, memory, and head and neck movements. If the results of the test indicate central nervous system dysfunction, the patient is usually referred to a neurologist (specialist in the central nervous system).

Several different scans are done to locate the tumor. Two of the most common are the computed tomography (CT or CAT) scan and magnetic resonance imaging (MRI). A CT scan uses x-ray images taken from many angles and computer reconstruction to show parts of the body in cross section. This helps to locate and estimate the size the tumor, and provides information on whether it can be surgically removed. MRI uses magnets and radio waves to create more detailed cross-sectional scans than computed tomography. There are many variations on these two scans that use dyes or radioactive materials to provide information about blood flow around the tumor and help determine whether the tumor can be surgically removed.

Treatment team

A neurosurgeon (a surgeon that specializes in the nervous system) will most likely lead the treatment team. A radiologist that specializes in nervous system radiology will interpret CT and MRI scans. Depending on the treatment plan, other members of the team may include a radiation oncologist (a specialist in radiation therapy ), radiation technicians, and nurses with special training in assisting cancer patients.

Clinical staging, treatments, and prognosis

Staging of chordomas is less important in developing a treatment plan than it is for some other cancers, since chordomas rarely spread from their original location. If the tumor is in a location where it can safely be removed without damaging other nerves or structures, surgery is the preferred treatment.

But chordomas can be difficult to treat because the location of the tumor often makes it inoperable or impossible to remove completely. This is especially true of chordomas located at the base of the skull. When the tumor is inoperable, radiation therapy is the preferred treatment. Proton therapy, also called charged particle therapy, is a type of radiation treatment that spares the tissues around the tumor. For this reason, it is sometimes recommended for chordoma around the skull. One drawback of proton therapy is that the procedure is only offered at a few sites around in the United States. It is always appropriate to get a second opinion before agreeing to any treatment plan. Some insurers require second opinions before surgery.

The success of the treatment plan depends almost entirely on the location of the tumor. Chordomas can recur after either surgery or radiation therapy. They rarely spread (metastasize) to other parts of the body.

Alternative and complementary therapies

Alternative and complementary therapies range from herbal remedies, vitamin supplements, and special diets to spiritual practices, acupuncture, massage, and similar treatments. When these therapies are used in addition to conventional medicine, they are called complementary therapies. When they are used instead of conventional medicine, they are called alternative therapies.

No specific alternative therapies have been directed toward chordoma. However, good nutrition and activities, such as yoga, meditation, and massage, that reduce stress and promote a positive view of life have no unwanted side effects and appear to be beneficial. Alternative and experimental treatments are normally not covered by insurance.

Coping with cancer treatment

Cancer treatment, even when successful, has many unwanted side effects. Radiation therapy may causefatigue , and nausea and vomiting . Bladder control and sexual function may be impaired after surgery on sacral chordomas. Mental functions may be impaired because of inoperable chordomas near the brain.

Discovering one has cancer is a traumatic event. Not only is one's health affected, one's whole life suddenly revolves around trips to the doctor for cancer treatment and adjusting to the side effects of these treatments. As this is a stressful time for both the cancer patient and family members, support groups and psychological counseling may be helpful. Many national organizations that support cancer education can provide information either in person or through on-line support and education groups.

Clinical trials

Chordoma is a rare tumor. In 2001, there were no clinical trials related to its diagnosis or treatment. However, the selection of clinical trials underway changes frequently. Current information on what clinical trials are available and where they are being held can be found by entering the search term "chordoma" at the following websites:

• National Cancer Institute <http://cancertrials.nci.nih.gov> or (800) 4-CANCER.
• National Institutes of Health Clinical Trials <http://clinicaltrials.gov>.
• Center Watch: A Clinical Trials Listing <http://www.centerwatch.com>.

Prevention

There is no way to prevent chordoma. There appear to be no environmental factors that affect the development of this tumor.

Resources

ORGANIZATIONS

American Brain Tumor Association. 2720 River Road, DesPlaines, IL 60018. (847) 827-9910. Patient line (800) 886-2282. <http://www.abta.org>.

Tish Davidson, A.M.

KEY TERMS

Sacrum

—The last five vertebrae (bones) of the spinal column, which are fused into a single mass commonly called the tail bone.

QUESTIONS TO ASK THE DOCTOR

• What kinds of tests will you do?
• What will these tests tell you about my cancer?
• What are my treatment options?
• How will my treatment affect my daily life?
• Since chordoma is a rare tumor, how much experience do you have with it?
• Are there hospitals that specialize in the treatment of chordoma where I might receive treatment unavailable here?