Anaplastic oligodendroglioma is a rare type of brain tumor that typically affects adults under age 45. Although there’s no cure, treatments may involve surgery, chemotherapy, and radiation.

Anaplastic oligodendroglioma (AO), also known as high grade oligodendroglioma, is a cancerous type of tumor that usually develops in the frontal lobes of the brain.

“Anaplastic” refers to cancer cells that are unusual in size and don’t look like regular cells.

The term “oligodendro” is from the Greek words meaning “small and tree-like.”

Gliomas are tumors that grow from glial cells. Glial cells are nervous system cells that protect the neurons that send information back and forth to your brain.

About 5% of brain tumors are oligodendrogliomas.

Is oligodendroglioma cancer?

Oligodendrogliomas may be benign (noncancerous) or malignant (cancerous). They’re rare tumors that affect glial cells called oligodendrocytes.

Doctors assign a grade to oligodendrogliomas based on factors such as their location, whether they’ve spread, and their genetic characteristics:

  • Grade 2: These are benign, low grade tumors that tend to grow slowly and may undergo successful treatment.
  • Grade 3: High grade, or anaplastic, oligodendrogliomas are malignant. They spread quickly to your brain and may be difficult to remove.

The most common symptom of AO is a seizure. About 60% of people have a seizure before their diagnosis.

Other symptoms may include:

When to contact a doctor

The earlier doctors can diagnose and treat AO, the better your outlook may be. If you’re experiencing any of these symptoms, consider meeting with a doctor to rule out other causes:

Because AO symptoms may be similar to those of other brain problems, a doctor may perform some of the following procedures to diagnose it:

  • Non-contrast-enhanced CT scan: Usually the first procedure, this type of CT scan shows the coarse calcification and other signs of AO.
  • MRI: An MRI provides more information than a CT scan, such as showing the extent of AO.
  • Biopsy: A brain biopsy can test tissue surgically removed from the tumor for the molecular markers (IDH or 1p19q) associated with AO.

Treatment for AO varies depending on the location of the tumor, your overall health, and surgical risk factors.

Surgery that removes as much of the tumor as possible is usually the first treatment for AO.

Because oligodendrogliomas can spread from your tumor into your healthy brain tissue, it’s often not possible to completely remove the tumor.

After surgery, treatment depends on factors such as your age, how much of the tumor remains after surgery, and its location.

Even after surgery for AO, doctors frequently recommend additional treatment, which may include:

The outlook for people with AO depends on the tumor size, location, and other factors. Early diagnosis and a successful response to treatment may help improve your prognosis.

A 2022 French study involving 190 people with AO compared the characteristics of the 44 people who survived fewer than 5 years with those of the 146 people who survived longer.

People who survived fewer than 5 years had some of the following characteristics:

  • older than 60 years
  • more advanced disease at diagnosis
  • increased cognitive dysfunction
  • larger tumors
  • treated with chemotherapy or radiotherapy instead of surgery

How long can you live with anaplastic oligodendroglioma?

The average survival rate for people after receiving an AO diagnosis is 3.5 years.

However, about 36% of people with AO survive for at least 10 years after their diagnosis.

The cause of AO is unknown.

According to the National Cancer Institute, people who have been exposed to radiation or inherited certain genetic changes may have a higher risk.

Although it can occur at any age, AO most often affects people 35–44 years old.

It’s rare in children. If it does develop, it typically occurs when children are between 6 and 12 years old.

AO more commonly occurs in people who are:

  • male
  • white
  • non-Hispanic

The following are answers to some frequently asked questions about AO.

What is the survival rate for anaplastic oligodendroglioma?

According to 2019 research, the average survival rates for people after an AO diagnosis are as follows:

  • 1 year: 78.7%
  • 3 years: 60%
  • 5 years: 50.2%
  • 10 years: 36.2%

Is anaplastic oligodendroglioma curable?

There is no cure for AO, but treatment options include surgery, chemotherapy, and radiation therapy.

What is the difference between oligodendroglioma and anaplastic oligodendroglioma?

Doctors classify oligodendroglioma tumors as grade 2. They usually occur between 25 and 45 years old, grow slowly, and are benign. They are shaped like a fried egg.

Doctors classify AO as grade 3. They grow faster and commonly occur about 10 years later than grade 2 oligodendrogliomas. They are more difficult to surgically remove because they spread into surrounding brain tissue.

It may be possible for grade 2 oligodendroglioma to progress to grade 3 AO due to genetic changes.

Can oligodendroglioma turn into glioblastoma?

Oligodendroglioma is a different type of brain tumor with different genetic characteristics than glioblastoma, the most common type.

Classified as grade 4, glioblastoma is malignant and extremely aggressive. It affects glial cells called astrocytes, while oligodendroglioma affects glial cells called oligodendrocytes.

However, in rare cases, an oligodendroglioma may eventually progress into a higher grade tumor, such as a glioblastoma. This may happen due to molecular and genetic changes in the tumor cells.

The outlook for people with anaplastic oligodendroglioma depends on factors such as the size and location of the tumor.

Although there is no cure for AO, doctors can treat this rare type of brain tumor with surgery, chemotherapy, and other treatments.