A tumor that develops in the central nervous system and negatively affects the brain or spinal cord (rarely) is called an oligodendroglioma. It usually begins to develop in the glial cells (the supportive cells of the nervous system). In general, this is a treatable tumor even if it is malignant (cancerous).
The cells where this tumor develops are called oligodendrocytes. They are a type of glial cells that support the nervous system and protect neurons that send signals within, to, and from the brain. Usually, the tumors that develop in the glial cells are called gliomas. Moreover, oligodendrogliomas account for 5% to 15% of all gliomas and approximately 4% of all brain tumors. In addition, there are about 24,000 new cases of oligodendrogliomas worldwide.
Types of Oligodendrogliomas
The WHO (World Health Organization) grading scale ranges from grade 1 to grade 4. This type of glioma is divided into 2 types under the WHO grading scale. For example:
- Oligodendrogliomas WHO grade 2 – This type is also known as “low-grade oligodendrogliomas”. In such cases, the tumor grows slowly and tends to respond well to treatment.
- Oligodendroglioma WHO grade 3 – This type is also called high-grade oligodendrogliomas (previously known as anaplastic oligodendrogliomas). These tumors are malignant because they are more aggressive. If you develop this type of oligodendroglioma, it may spread more easily, and it is difficult to treat.
What Are Oligodendrocytes?
The name of this central nervous system tumor comes from several Greek words. For example:
- Oligo- (small)
- -dendro (tree-like)
- -cytes (cells)
In normal circumstances, each neuron has a primary cell body with an arm-like extension (axon). Most of them have a protective layer (myelin sheath) around their axon. It helps protect the axon and maintain signal speed as it passes through the neuron.
However, oligodendrocytes have a primary body and multiple arm-like extensions that wrap around the axons (about 30 to 40 nearby neurons).
Symptoms
Usually, this type of cancer does not cause any symptoms in the early stages. However, if it advances, you may experience some symptoms. The most common of them include headaches or seizures. Approximately 80% of people with this type of cancer will experience at least a seizure. It occurs because oligodendrogliomas mostly affect the cerebral cortex (a part of the brain’s surface). Furthermore, this part of the brain controls multiple abilities that we use each day, including vision, language, muscles, and others.
Furthermore, this type of glioma can also cause focal symptoms. They often indicate a problem that is focused in a specific part of the brain. In most cases, it negatively affects a body part or an ability. Examples include:
- Problems with speaking or understanding other people (aphasia)
- Vision problems (such as blurred vision, double vision, loss of vision, and others)
- Memory loss
- Difficulty concentrating or thinking
- Hearing loss (deafness)
- Muscle weakness or paralysis (especially on one side of the body or face)
Immediately contact your healthcare professional if you or a loved one experiences any of the symptoms listed above.
Causes
This type of glioma occurs due to 2 specific DNA mutations (changes). These include:
- 1p/19q co-deletion – In general, chromosomes are the compressed DNA “data” that cells use as an instruction manual. In some cases, some errors may happen when chromosomes are copied as the cells reproduce. Most of the time, people with oligodendrogliomas have deletions on the short arm of chromosome 1 and the long arm of chromosome 19.
- IDH1 or IDH2 mutation – These genes contain specific instructions that tell the body to produce an enzyme (isocitrate dehydrogenase or IDH). This enzyme is used in metabolism. If you develop mutations in the IDH1 or IDH2 genes, it may lead to oligodendrogliomas.
Risk Factors
Currently, there are no confirmed risk factors for this type of glioma. However, some research suggests that previous radiation therapy may increase your risk of developing it. Healthcare professionals continue to study the role of radiation therapy in the development of oligodendroglioma. In addition, this type of glioma is mostly diagnosed in people between the ages of 40 and 50.
What Happens if an Oligodendroglioma is Left Untreated?
People who develop this type of glioma may experience some complications. However, these effects of oligodendroglioma depend on several factors. For example, the location and severity of the cancer, existing health problems, and others. Check below some complications that may occur in people with oligodendrogliomas:
- Malignant transformation – Sometimes, people with low-grade oligodendrogliomas may turn into cancerous tumors.
- Strokes or other circulatory-related issues – This tumor usually grows more and more, which takes up more space in the skull. As a result, it may displace the brain tissue around it.
- Skull structure changes – Usually, tumors are calcified, meaning they harden because of Calcium deposits. When it occurs outside the brain, it may cause damage to the skull bones.
- Cognitive and behavioral changes – These include problems with memory, confusion, and other problems.
- Language and speech problems
- Vision changes
- Problems with coordination and balance
- Recurrent oligodendroglioma
- Malignant degeneration
Moreover, cancer treatments used for this type of glioma may also cause some complications. Examples include:
- Radiation necrosis (tissue death)
- Cognitive deficits
- Delayed growth and development
- Nausea
- Vomiting
- Gastrointestinal issues
- Myelosuppression (low blood cell counts)
- Infertility
- An increased risk of infections or bleeding
This document does not contain a full list of oligodendroglioma complications. In any case, you can talk with your physician about ways to reduce the risk of developing them.
How to Prevent Oligodendroglioma?
Unfortunately, there is no way to prevent this type of cancer because healthcare professionals do not fully understand what exactly causes it. However, if you have a family history of gliomas, you can perform regular tests to make sure it does not appear. For more details, discuss it with your doctor.
Diagnosis
Commonly, an oligodendroglioma is often diagnosed with a physical and neurological examination, diagnostic imaging, brain biopsy, and pathology testing. In some cases, your doctor may ask some questions about your symptoms and medical history to get more clues about the disease. The following imaging tests are used to determine the exact location and size of the tumor. Examples include:
- CT (computerized tomography) scans – In most cases, this is the primary test used after a person has a seizure or focal symptom. While the bones appear bright on X-rays and CT scans because of Calcium, oligodendrogliomas also appear bright because they have Calcium deposits.
- MRI (magnetic resonance imaging) scans – This imaging test uses a magnet and radio waves to produce detailed images of different structures and organs in the body. In such cases, MRI scans help identify the exact location of the tumor.
However, imaging tests alone cannot confirm an oligodendroglioma. These tests show a developing tumor in the brain, but to confirm this type of glioma, doctors often use a brain biopsy or pathology testing.
During a brain biopsy, physicians will take a small sample of the tumor for testing. They will look at this sample under a microscope to check for abnormal cells. They may also perform a blood test to check for the mutated genes often present in people with oligodendrogliomas.
Treatment
Usually, oligodendrogliomas are treated with surgery, chemotherapy, and radiation therapy.
Surgery
This is usually the primary treatment. It is used to remove the tumor as much as possible. Surgeons may also remove some healthy tissue around the tumor to make sure there are no remaining cancerous cells. Generally, success rates depend on the type and size of the tumor, the exact location of the tumor, and other factors. Sometimes, your doctor may also recommend chemotherapy or radiation therapy to improve the effectiveness of the treatment.
Chemotherapy
This treatment involves strong medications to destroy cancer cells throughout the body. Check below the most common types of chemotherapy used for people with oligodendrogliomas:
- The PCV regimen – The name of this type of chemotherapy comes from the 3 medicines it consists of. These include Procarbazine, Lomustine, and Vincristine.
- Temozolomide – Usually, doctors recommend this medicine when the PCV regimen does not work. According to some studies, Temozolomide’s effectiveness is very similar to the PCV regimen.
Furthermore, doctors may prescribe chemotherapy to shrink a large tumor before surgery or to destroy cancerous cells that may remain even after a successful surgery.
Radiation Therapy
This therapy uses powerful energy beams to destroy the tumor. Commonly, this energy comes from X-rays, protons, or other sources. Moreover, this cancer treatment can be recommended by doctors along with chemotherapy to improve the effectiveness of the treatment. In most cases, this treatment is used when surgery is not an option.
Frequently Asked Questions
What can I expect if I have an oligodendroglioma?
This type of glioma is a serious health condition that requires treatment as soon as possible. Otherwise, it may lead to life-threatening complications (such as permanent damage to the brain). However, oligodendrogliomas are often found in advanced stages because they do not cause symptoms in the early stages. So, people do not know they have this type of cancer. In some cases, it can be found accidentally during an imaging test done for other reasons.
Is oligodendroglioma cancer curable?
No, but there are some options that can treat it. You can get rid of this tumor and cancerous cells with surgery, chemotherapy, or radiation therapy. In rare cases, people may experience recurrent oligodendrogliomas.
Is oligodendroglioma fatal?
This type of cancer significantly reduces life expectancy, especially if it is left untreated. A better life expectancy is associated with people with low-grade oligodendrogliomas (slow-growing tumors). Ask your healthcare provider if you have additional questions.
