What is a chordoma?
Chordomas are rare malignant (cancerous) tumors that are found in the spine and skull. These tumors affect about 1 person in 1 million people per year. One to four percent of all primary bone tumors are chordomas.
Chordomas typically grow slowly. They are often found
in the front (anterior) part of the spine or base of the skull. They can occur at any point along the spine.
Common locations include the base of the spine (sacrum), the tailbone (coccyx), and the place where the spine meets the skull (skull base). There is bone called the clivus behind the back of the throat but in front of the brainstem. Chordomas there are called clival chordomas.
Who develops chordomas?
These tumors are mostly found in adults aged 40 to 70 years. A small percentage (about 5%) are found in children. Males develop chordomas about twice as often as females do.
Symptoms and Causes
What are the symptoms of a chordoma?
The symptoms depend on where the chordoma is located. Symptoms can include:
- Visual problems, such as double vision
- Nerve or muscle weakness in the back, arms, or legs
- Runny nose
- Bowel or bladder problems
What causes chordomas?
There is evidence that a person can have a higher risk of chordoma by inheriting an altered gene from a parent. However, other cases of chordoma happen to people who have no family history of chordomas.
There are reports that children who have a genetic condition called tuberous sclerosis complex have a higher incidence of developing chordomas.
Diagnosis and Tests
How is a chordoma diagnosed?
A biopsy will be done to diagnose a chordoma and to differentiate it from other types of tumors. The tissue is examined under a microscope, the chordoma can have one of three subtypes: conventional (or classic), chondroid, and dedifferentiated (also called sarcomatous).
Conventional chordomas are most common. They grow slowly but are malignant. Chondroid chordoma grows even more slowly than a conventional chordoma. They are mostly found at the base of the skull. Dedifferentiated chordomas grow quickly.
Because radiological testing can be confusing, chordomas are identified by two types of markers: cytokeratins and brachyury. The brachyury protein is also found in masses that have developed from the notochord, which is the support structure in embryos.
CT and MRI scans are also used to develop strategies for treatment.
Management and Treatment
How is a chordoma managed and treated?
Surgery is the best option for chordomas located at the sacrum and in the mobile spine. Complete surgical removal tends to delay reoccurrence and is associated with longer survival rates. In these procedures, the tumors are removed along with tissue around it. This is generally followed by external-beam radiation treatments.
For clival chordomas and other skull-base chordomas, great effort is taken to save nerve function. This often involves doing surgery with special instruments and entering through the nose. It might not be possible to remove all of the tumor. Radiotherapy is used after surgery. However, the doses that are effective against the tumors are higher than can be tolerated by the spinal and brain tissues. Stereotactic radiosurgery, however, can deliver such high-dose radiation with lower risk to brain and nerve tissue than conventional fractionated radiotherapy, and may be an effective treatment in some cases.
Although tests are underway, chemotherapy does not seem to be effective against chordomas.
Outlook / Prognosis
What is the prognosis for someone with a chordoma?
There is a high rate of recurrence. Those diagnosed with chondroid chordomas tend to have a better prognosis than either conventional or classic chordomas. Dedifferentiated chordomas tend to grow faster and will more often grow elsewhere (metastasize). The outlook for dedifferentiated chordomas is the least optimistic.
Younger patients are more likely to develop metastatic disease. Recurrence is linked to metastasis. Survival rates depend on the location of the tumor and location of metastasis.