Chordoma

What is chordoma?

Chordoma is a rare form of bone cancer. The tumors can develop anywhere in the spine but are most commonly found in the lower back (sacrum) or at the base of the skull. Chordomas may press on critical parts of the brain or spine, causing symptoms including blurred vision, headaches, numbness and weakness.

Classified as malignant (cancerous), these tumors grow slowly but have potential to metastasize (spread). Despite their gradual development, chordomas can be difficult to treat because they grow near important tissues, such as nerves and blood vessels. Removing all of a chordoma without harming healthy tissue can be challenging.

Chordomas most frequently affect adults in their 50s and 60s. Just 5% of chordomas are discovered in children, and in the United States, only 300 children are diagnosed with them each year. In children, chordomas are found slightly more often in females than males, but in adults, men are more likely to be diagnosed than women.

Causes of chordoma

The causes aren't fully understood, but it's thought that they are linked to genetic mutations (changes in a gene's DNA). Most people with chordomas have a mutation in a gene that plays an important role in embryo development. This gene helps shape the notochord, the early form of the spine in a growing embryo. Notochord cells usually disappear before or soon after birth. When that doesn't happen, they can become cancerous and turn into chordomas.

Types of chordoma

There are four types of chordoma. The classifications are based mainly on their appearance – as seen in imaging scans and how the cells look under a microscope – and on how quickly they grow.

• Conventional (classic) chordoma. This is the most common type. It typically grows slowly and the cells have a bubbly appearance.
• Poorly differentiated chordoma. This rare type tends to be faster growing and more likely to spread. It most commonly affects children and young adults.
• Dedifferentiated chordoma. This type is very rare. It's typically the fastest growing and most aggressive type, and it's most commonly found in children.
• Chondroid chordoma. This type is more difficult to diagnose because the cells look similar to the cells in chondrosarcoma, another type of bone cancer. Chondroid chordomas typically behave like conventional chordomas.

Symptoms of chordoma

Chordoma symptoms depend on the size and location of the tumor. As it gets bigger, the tumor may press on parts of the brain or the spinal cord, with symptoms corresponding to the affected area.

A chordoma at the base of the skull might produce the following symptoms:

• Abnormal eye movements
• Difficulty swallowing
• Double vision
• Facial pain
• Headaches
• Nausea and vomiting

A chordoma in the spinal cord may cause pain, weakness or numbness in the back, arms or legs. A chordoma in the tailbone can create bladder or bowel problems.

Diagnosis of chordoma

If your child’s symptoms lead their doctor to suspect a chordoma, your child will have imaging tests. These can include:

• X-rays. These images show bones and soft tissues, and can reveal a tumor's presence.
• Magnetic resonance imaging (MRI) scan. Using radio waves and a powerful magnet, this technique can not only reveal the presence of a chordoma but show the degree to which adjacent tissues are affected.
• Computed tomography (CT) scan. Using X-rays linked to a computer, this type of scan creates detailed images and may be used if MRI results don't clearly indicate a chordoma.
• Bone scan. For this test, a radiotracer (a small amount of radioactive material) is injected into a vein and a special camera takes pictures that show how much of it collects in the bones. This allows doctors to assess bone density in and around the affected areas and can help them to understand the chordoma's severity.

Confirming a chordoma diagnosis requires a biopsy – removing and analyzing a sample of the tumor's cells. If the tumor is accessible through the skin, your child's doctor may be able to get a sample using a needle. Otherwise, the biopsy sample may be taken during surgery to remove the tumor.

Treatment of chordoma

The treatment approach for chordoma depends on the tumor's size and location as well as whether it has invaded nerves or other tissues. Complete removal of the tumor followed by radiation provides the best long-term outcomes. Some chordomas are challenging to treat, particularly large ones that are difficult to fully remove.

For most children, the first step is surgery to remove as much of the tumor as possible. This is followed by radiation therapy to destroy remaining cancer cells and reduce the risk of recurrence.

Chordoma removal with minimally invasive surgery

When a chordoma is at the skull base, the patient may be a candidate for minimally invasive skull base surgery. This involves removing the tumor endoscopically, using small, special tools passed through the nasal passages. Because the tumor is removed through the nose, there's no need to make incisions in the face or scalp or drill into the skull.

Follow-up chordoma care

Chordomas often recur, so children who have been treated for one need to be monitored with periodic MRI scans. They may need additional surgery or radiation.

Knowing that dealing with chordoma can be a lifelong issue, the expert team at UCSF aims to support not only long-term survival but also quality of life. Our focus is on minimizing the immediate and long-term side effects of chordoma treatment. In addition, UCSF researchers are investigating new ways to treat chordoma, including immunotherapy, a method that uses the patient's own immune system to fight their cancer. Your child may be eligible to participate in clinical trials of promising treatments for chordoma. Learn more about the process and benefits of participating in a clinical trial.