A chordoma is a form of bone cancer that can occur anywhere along the length of the spine, from the base of the skull to the lower back. When it occurs at the base of the skull, it is known as skull base chordoma. The tumor originates in the clivus bone. Because of its location in the base of the skull, it commonly affects vital structures, such as the nerves that control movement of the face, eyes, and swallowing.
Chordomas are rare cancers. There are about 300 new cases in the U.S. annually. Although anyone can develop a chordoma at any age, a skull base chordoma is diagnosed most often around age 49, and in men more often than in women.
Skull base chordomas are divided into 3 types:
Conventional. This is the most common type of chordoma and is sometimes called a classic chordoma. It is more aggressive than a chondroid chordoma, but less aggressive than dedifferentiated.
Chondroid. This is the least aggressive type of chordoma.
Dedifferentiated. The dedifferentiated form of chordoma is more aggressive and grows more quickly than the other types.
If you have a skull base chordoma, the most common symptoms that you will experience are related to pain or changes in nerve function. These can include:
Paralysis of the facial muscles
Techniques typically used to diagnose cancer will be used to identify a skull base chordoma. These may include various scans, such as CT scans or MRI, a blood test, or a biopsy. Testing may be done by a specialist, such as a neurologist or a neurosurgeon.
One common misdiagnosis that can occur with a chordoma is confusing it with a chondrosarcoma. Both types of tumors can occur in similar locations in the body, and they look similar as well. Chondrosarcomas tend to respond better to radiation and have a better outlook.
The primary treatment for a skull base chordoma is surgery to remove as much of the tumor as possible. This is often an aggressive procedure that leads to some side effects, but it offers the best chance for long-term survival. You and your health care team should weigh the risks and benefits of the procedure before the surgery.
Once the surgery is complete, an aggressive course of radiation therapy is used to kill the surrounding tumor cells. Proton beam radiation is often used because it can focus on the needed area without exposing any critical organs and structures around it to radiation. Proton beam radiation offers the advantage of increasing the tumor dose while minimizing the dose to the adjacent normal tissue. Other forms of radiation are sometimes used as well.
Chemotherapy is typically not effective in treating a skull base chordoma. Currently, no drugs are approved for treating chordomas, but some have shown effectiveness in clinical trials. These drugs include Gleevec (imatinib), Erbitux (cetuximab), Iressa (gefitinib), and Tarceva (erlotinib).
Skull base chordomas are rare disorders, and it is not known how to prevent them.
A skull base chordoma is a malignant and potentially life-threatening tumor. Patients need to be prepared for a difficult fight against the illness, one that will involve challenging treatments, such as surgery and radiation therapy.
The average life expectancy for someone with a chordoma is about 7 years. Survival rates at 5 years are 58%, and 40% at 10 years. Outcomes from chordoma treatment have improved in recent decades. Still, it's best to address potential end-of-life issues as part of a skull base chordoma management plan.