Oligodendroglioma is a growth of cells that starts in the brain or spinal cord. The growth, called a tumor, begins in cells called oligodendrocytes. These cells make a substance that protects nerve cells and helps with the flow of electrical signals in the brain and spinal cord. Oligodendroglioma comes from cells that support the nerve cells, not the nerve cells themselves.

Oligodendroglioma usually forms in the brain. More rarely, it can form in the spinal cord. As the tumor grows, it can press on brain or spinal cord tissue and cause symptoms. Symptoms depend on which part of the brain or spinal cord is affected.

Oligodendrogliomas are rare. They are most common in adults, but they can happen at any age. Most of the time, this tumor grows slowly. Symptoms include seizures, headaches, and weakness or disability in a part of the body.

Treatment is with surgery, when possible. Sometimes surgery can't be done if the tumor is in a place that makes it hard to reach with surgical tools. Other treatments may be needed if the tumor can't be removed or if it's likely to come back after surgery. If you are diagnosed with oligodendroglioma, your healthcare team likely will monitor the tumor, even after treatment.

The cause of oligodendroglioma often isn't known. This tumor starts as a growth of cells in the brain or, more rarely, in the spinal cord. It forms in cells called oligodendrocytes. They protect nerve cells and help with the flow of electrical signals in the brain.

Oligodendroglioma happens when oligodendrocytes develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time.

In tumor cells, the DNA changes give different instructions. The changes tell the tumor cells to grow and multiply quickly. Tumor cells can keep living when healthy cells would die. This causes too many cells.

To diagnose oligodendroglioma, healthcare professionals look for DNA changes called IDH mutations. They also look for specific changes in the chromosomes of the tumor cells. The medical description for this type of tumor is oligodendroglioma, IDH-mutant, 1p/19q-codeleted.

The tumor cells form a growth that may press on nearby parts of the brain or spinal cord as the growth gets bigger. Sometimes the DNA changes turn the tumor cells into cancer cells. Cancer cells can invade and destroy healthy body tissue.

You may start by seeing your primary care provider. Or, you may be referred immediately to a specialist. This may be a doctor who specializes in cancer, called an oncologist. You also may see a surgeon who specializes in operating on the brain and spinal cord, called a neurosurgeon.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do ahead of time, such as fasting before having a specific test. Make a list of:

• Your symptoms, including any that seem unrelated to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medications, vitamins or other supplements you take, including the doses.
• Questions to ask your health professional.

Take a family member or friend along, if possible, to help you remember the information you're given.

For oligodendroglioma, some basic questions to ask your healthcare professional include:

• Do I have cancer?
• If the tumor isn't cancerous, do I still need to have it removed?
• Do I need more tests?
• What are my treatment options?
• What are the potential complications of these treatment options?
• Do any of the treatments cure my cancer?
• Can I have a copy of my pathology report?
• How much time can I take to consider my treatment options?
• Are there brochures or other printed materials that I can take with me? What websites do recommend?
• What would happen if I chose not to have treatment?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you several questions, such as:

• When did your symptoms begin?
• Have your symptoms been continuous or occasional?
• How bad are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?

What you can do in the meantime

Avoid doing anything that seems to worsen your signs and symptoms.

Risk factors for oligodendroglioma include:

• History of radiation exposure. A history of radiation to the head and neck can increase a person's risk.
• Adult age. This tumor can happen at any age. But it's more often found in adults in their 40s and 50s.
• White race. Oligodendroglioma happens most often in white people who don't have Hispanic ancestry.

There is no way to prevent oligodendroglioma.

Your healthcare team can use several steps to help diagnose oligodendroglioma.

• Neurological exam. During a neurological exam, you're asked about your symptoms. Your vision, hearing, balance, coordination, strength and reflexes are checked. Problems in one or more of these areas may give clues about the part of the brain that could be affected by a brain tumor.

• Imaging tests, such as an MRI. Imaging tests can help determine where the brain tumor is and its size. MRI is often used to diagnose brain tumors. An MRI uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body. When you lie inside an MRI machine, the magnetic field inside works with radio waves and hydrogen atoms in your body to create cross-sectional images — like slices in a loaf of bread.

  Your healthcare team may use a special type of MRI called a functional MRI of the brain. It produces images of blood flow to certain areas of the brain. Functional MRI can be used to show which parts of the brain are handling critical functions, language and movements. This information can help guide decisions when considering someone for brain surgery.

• Removing a sample of tissue for testing. The healthcare team takes a sample of tissue from the tumor to study in the lab. When possible, the sample is taken during surgery to remove the tumor. If the tumor can’t be removed with surgery, the sample may be collected with a needle in a biopsy procedure. Which method is used depends on your situation and the location of the tumor.

• Microscope exam and genetic tests. The tissue sample removed during surgery or a biopsy goes to a lab for testing. The lab team views the sample under a microscope. This is called histology testing. Tests can show what types of cells are involved. Special tests can show detailed information about the tumor cells. For example, a test may look at the changes in the tumor cells' genetic material, called DNA. The testing can determine whether the tumor cells have the DNA changes that are specific to oligodendroglioma. Your healthcare team uses this information to better understand how the tumor might change and determine which treatments might help.

  The tests also help rule out similar gliomas called astrocytoma and glioblastoma.

Oligodendroglioma grade

Oligodendrogliomas are given a grade of 2 or 3, which reflects how aggressive they are.

Grade 2 tumors grow slowly. They usually are treated with surgery, sometimes followed by radiation or chemotherapy.

Grade 3 tumors are more aggressive. Treatment usually includes surgery, radiation and chemotherapy. Grade 3 tumors also may be called anaplastic oligodendroglioma.

Prognosis

Your healthcare team uses all the information from your diagnostic tests to understand your prognosis. The prognosis is how likely it is that the oligodendroglioma can be cured. Things that can affect the prognosis include:

• The grade of the tumor.
• How quickly the tumor is growing.
• Where the tumor is within the brain or spinal cord.
• Whether the tumor can be removed completely with surgery.
• The success of other treatments.
• Your overall health and well-being.

What is the survival rate for people with oligodendroglioma?

Long-term survival is possible for many people with oligodendrogliomas. But these tumors generally shorten the lifespan. That's because they can keep growing and can be hard to treat.

The relative five-year survival rate for oligodendroglioma is 79.5%. This means that people diagnosed with the tumor are 79.5% as likely to live at least five years as people who don't have the tumor.

Newer evidence points to improved outcomes for oligodendroglioma. Survival rates vary depending on the tumor's grade and the age of the person when diagnosed. Oligodendrogliomas are given a grade of 2 or 3, which reflects how aggressive they are.

Grade 2 tumors grow slowly. People with grade 2 oligodendroglioma often live more than 10 years after treatment, especially if they are healthy, younger and their tumor is entirely removed. Some research shows a median survival rate of 18 to 20 years for grade 2 tumors. This means that half the people will live longer than 20 years, and half will live less than 20 years.

Grade 3 tumors, also called anaplastic oligodendroglioma, grow more quickly. Life expectancy is shorter for grade 3 oligodendroglioma. Long-term research trials show a median survival rate of 14 years for grade 3 tumors. This means that half the people will live longer than 14 years, and half will live less than 14 years. About 20% of people with anaplastic oligodendroglioma live five years or less.

People who are younger and generally healthy have a better chance of living longer. Regular monitoring with MRI and effective therapy is important to catch potential recurrences early.

Factors that usually predict a worse outcome for oligodendrogliomas include:

• Older age at diagnosis, especially people over 60.
• Being assigned male at birth.
• Having trouble with movement, speech or other brain-related activities.
• Poorer overall health.
• Tumor that is located in hard-to-reach areas of the brain.
• Tumor size larger than 2 inches (4 to 5 centimeters).
• No seizures when the tumor was first found.

What can you do?

While not everything is under your control, there are steps you can take to help improve your chances of a good outcome. You can:

• Follow up as told by your healthcare team for monitoring and regular scans.
• Maintain your health as suggested by your healthcare professional.
• Report any new symptoms quickly.
• Take part in supportive care programs if offered by your healthcare team.

Treatment for oligodendroglioma depends on the tumor's size and location, along with your symptoms, age and general health.

Oligodendroglioma treatments include:

• Surgery to remove the tumor. The goal of surgery is to remove as much of the tumor as possible. The brain surgeon, who also is called a neurosurgeon, works to remove the tumor without harming healthy brain tissue. One way to do this is called awake brain surgery. During this type of surgery, you're awakened from a sleeplike state. The surgeon may ask questions and monitor the activity in your brain as you reply. This helps show the important parts of the brain so the surgeon can avoid them.

Other treatments also may be needed. After surgery, these might be recommended if any tumor cells remain or if there's an increased risk that the tumor will come back. Other treatments include:

• Radiation therapy. Radiation therapy uses powerful energy beams to kill tumor cells. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine sends beams to exact points in your brain. Radiation therapy is sometimes used after surgery. It may be combined with chemotherapy. Radiation therapy is recommended for grade 3 oligodendroglioma.
• Chemotherapy. Chemotherapy uses strong medicines to kill tumor cells. Chemotherapy is often used after surgery to kill any tumor cells that might remain. It can be used at the same time as radiation therapy or after radiation therapy is finished.

After surgery, a combination of radiation therapy and chemotherapy generally is best for managing oligodendroglioma. The exact regimen and timing can be adjusted based on how much of the tumor was removed during surgery. Age, health, genetic markers and symptoms are other factors to consider.

Your healthcare team also may recommend watchful waiting, with regular monitoring to see how the tumor is growing. You may need to have regular medical imaging scans to look for any changes in the tumor. If treatment, such as surgery, chemotherapy or radiation, shrinks the tumor but it comes back later, it's called recurrent oligodendroglioma. This means more treatment may be needed.

Other treatment options

• Medicines. After your surgery, medicines may be an option if you are at lower risk and you don't have any symptoms. Your healthcare team may recommend a medicine to help slow tumor regrowth. One newer medication called vorasidenib (Voranigo) shows promising results, but safety and long-term benefits are still being studied.
• Clinical trials. Clinical trials are studies of new treatments. These studies give you a chance to try the latest treatment options. The risk of side effects may not be known. Ask a member of your healthcare team whether you can participate in a clinical trial.
• Supportive care. Supportive care, also called palliative care, focuses on providing relief from pain and other symptoms of a serious illness. Palliative care specialists work with you, your family and members of your healthcare team to provide extra support. Palliative care can be used at the same time as other treatments, such as surgery, chemotherapy or radiation therapy.

Oligodendrogliomas grow slowly, so symptoms may not occur for many years. Sometimes the condition is discovered when brain images are taken for another reason, such as severe headaches or a suspected concussion.

Seizures are usually the first symptom of oligodendroglioma. That's because these tumors often occur in the areas of the brain that support motor control. The brain tumor can disrupt the usual flow of the brain's electrical signals, which can cause a seizure.

Other symptoms of oligodendroglioma depend on the tumor size and location. They can include:

• Changes in behavior.
• Headaches.
• Memory problems.
• Numbness on one side of the body.
• Problems speaking.
• Problems thinking clearly.

When to see a doctor

If you notice ongoing symptoms that concern you, consider reaching out to a healthcare professional, clinic or trusted community health resource for advice.