What is oligodendroglioma?
Oligodendroglioma is a type of brain tumor known as a glioma. This tumor gets its name from oligodendrocytes, cells that cover and protect nerves in the brain. Oligodendroglioma can be a low-grade glioma or a high-grade glioma.
Oligodendrogliomas occur most often in the white matter of the cerebrum. White matter is a network of pale-colored nerve fibers in the brain. White-matter cells transmit messages from one part of the brain to another.
Most oligodendrogliomas occur in adults. They are rare in children and teens. These tumors make up less than 1% of brain tumors in children younger than 14.
Treatment usually includes surgery to remove as much of the tumor as possible. Radiation therapy is often used to kill remaining cancer cells. Chemotherapy may also be used.
Survival rates for pediatric oligodendroglioma depend on the tumor grade and success of surgery. Patients with low-grade tumors that are completely removed by surgery have a survival rate above 90%.
Your child’s care team is the best source of information about your child’s case.
Symptoms of oligodendroglioma
An oligodendroglioma often grows slowly. It may be present for years before it causes problems. Signs and symptoms of oligodendroglioma depend on the child’s age, tumor size and location, and how fast the tumor grows.
Oligodendroglioma signs and symptoms may include:
- Seizures (most common)
- Changes in personality or behavior
- Headaches
- Vision problems
- Weakness or numbness on one side of the body
About half of patients experience seizures before diagnosis. Most patients (about 80%) will have seizures at some point during their illness.
Risk factors for oligodendroglioma
The cause of oligodendroglioma is unknown. But certain genetic changes in cells are linked to these tumors.
Oligodendrogliomas usually occur in adults. They are more common in males. Childhood oligodendrogliomas are most often seen in teens and young adults.
Diagnosis of oligodendroglioma
Tests to diagnose oligodendroglioma include:
- A physical exam and health history to learn about symptoms, general health, past illness, and risk factors.
- A neurological exam to measure brain function. This includes memory, vision, hearing, muscle strength, balance, coordination, and reflexes.
- An electroencephalogram (EEG) to check electrical activity in the brain
- Imaging tests such as magnetic resonance imaging (MRI) to identify the tumor, its size, and location.
- A biopsy to check for abnormal cells. A pathologist looks at the sample under a microscope to identify the type and grade of glioma.
- Other genetic and molecular testing of the tumor to show possible targets for targeted therapy.
Doctors are learning more about molecular changes and gene mutations (DNA changes) that occur in the tumor cells. Most oligodendrogliomas have a gene change that helps in the diagnosis. These changes are an IDH mutation (IDH1 or IDH2) and 1p19q codeletion. Understanding changes in tumor cells can help doctors plan treatments.
Staging of oligodendroglioma
Oligodendrogliomas are graded by how they look under the microscope. The more abnormal the cells look, the higher the grade. Oligodendrogliomas are usually grade 2 or 3.
- Grade 2 is considered low grade. The cells look like normal cells and grow slowly. Low-grade tumors are less likely to spread to other parts of the brain.
- Grade 3 is considered high grade. These tumors are called anaplastic oligodendrogliomas. They are more aggressive and can spread more easily.
Treatment of oligodendroglioma
Treatment of oligodendroglioma depends on:
- The type of tumor
- The tumor’s location
- Whether it has spread or come back
Aggressive tumors need more intensive treatment. Doctors also consider the patient’s age.
Surgery for oligodendroglioma
Surgery is the main treatment for oligodendroglioma. The goal is complete removal of the tumor (total gross resection). But it is not always possible to remove the whole tumor due to risk of damage to the brain.
In some cases, surgery is not possible due to the tumor’s location. Some patients with low-grade tumors may have surgery followed by observation. Other patients may have surgery followed by radiation and/or chemotherapy.
Radiation therapy for oligodendroglioma
Radiation therapy may be used after surgery to destroy cancer cells left behind. Radiation therapy depends on the type and location of the tumor and the age of the child. It is not used in young children because of the risk of side effects.
Chemotherapy for oligodendroglioma
Chemotherapy is sometimes used along with surgery and radiation therapy, especially for high-grade tumors.
Chemotherapy used for oligodendroglioma includes:
Other types of chemotherapy may also be used, especially in a clinical trial.
Some medicines used to treat oligodendrogliomas may cause fertility problems. Talk to your child’s care team about options to help protect fertility.
Targeted therapy for oligodendroglioma
Targeted therapies work by acting on, or targeting, specific features of tumor cells. Changes in the genes and proteins may control tumor cell growth and division. Your child’s care team may suggest targeted therapy if it could help treat your child’s disease.
Prognosis for oligodendroglioma
Oligodendroglioma is much more common in adults than children. Less is known about the prognosis for young patients. Overall, children have better outcomes than adults.
The 5-year survival rate for childhood oligodendroglioma is greater than 80%. But treatment outcomes can vary widely based on the success of surgery, age at diagnosis, features of the tumor, and other factors. Recurrence is common, even among long-term survivors.
Outcomes vary based on:
- Type and grade of the tumor. Low-grade oligodendrogliomas grow slowly and are less likely to recur. High-grade tumors can be harder to treat and often recur sooner.
- Whether surgery can completely remove the tumor. Children with no visible tumor after surgery have the best chance of cure.
- Whether the cancer has spread. Cancer that has spread to other parts of the brain is harder to treat.
- Location of the tumor. Tumors in the cerebrum or cerebellum have a better chance of cure than tumors in the middle of the brain or brainstem. This is because they are easier to remove with surgery.
- Whether the cancer comes back. Recurrent disease is harder to treat.
- Molecular or genetic features of the tumor. Scientists are studying whether certain changes in genes and cells of the tumor can make the disease easier to treat with targeted therapy.
Every case is different. Your care provider can give you more information about your child’s case.
Support for patients with oligodendroglioma
After treatment, your child will need ongoing follow-up care, lab tests, and routine MRI scans to monitor for recurrence or progression. Patients may need steroids and anti-seizure medicines for a time.
Recovery and long-term effects of oligodendroglioma in children and teens depend on features of the tumor and treatments received. Survivors of oligodendroglioma also should be monitored for late effects of therapy.
Your child’s care team will give you a survivorship care plan after treatment ends. This report includes needed tests and tips for a healthy lifestyle. Your care plan should also include referrals to support services such as neurology, rehabilitation therapy, school services, and psychology.
All cancer survivors should adopt healthy lifestyle habits. It is important to have regular medical checkups by a primary care physician.
Pediatric low-grade glioma as a long-term disease
Low-grade gliomas, including some oligodendrogliomas, are often a chronic or long-term disease. Although the long-term survival rate for low-grade glioma is high, the tumor often comes back or progresses over time.
Your child may need more treatments over many years of follow-up. This means the risk is higher for complications related to the tumor or treatment. There may also be times when the tumor shows growth on a scan, but the care team suggests observation instead of treatment.
Good communication and trust among your family, your child, and the care team are important.
Questions to ask your care team
