Glioma

5 min read

What is a glioma brain tumour?

A glioma is a type of brain tumour that has developed from cells that should have become healthy glial cells in the brain. Glioma brain tumours vary across the spectrum of low-grade (slow-growing) and to high-grade (faster-growing) and a poorer prognosis than low-grade.

What is a mixed glioma?

A mixed glioma is a glioma brain tumour that contains a mix of glial cells including astrocytes, oligodendrocytes and ependymal cells.

What is a glial cell?

Glial cells form a web of connective tissue to support the neurons (nerve cells) within the brain and spinal cord. Types of glial cells include astrocytes, oligodendrocytes, microglia and ependymal cells.

Why are there different names for different types of glioma brain tumours?

All glioma brain tumours tend to be named to reflect the type of cells that make up the majority of the tumour.

This is determined through a biopsy or a surgical operation where a sample of the tumour is viewed by clinicians through a microscope (known as histopathological assessment) and classified by the physical characteristics that can be observed (known as the phenotype).

Some glioma brain tumours have different names depending upon their grade: for example they may be called a low-grade glioma or a grade 4 glioblastoma multiforme (GBM).

Is glioma a low-grade (benign) or high-grade (malignant) brain tumour?

The grade of a glioma brain tumour gives an indication as to how the tumour is expected to behave (develop).

All brain and central nervous system (CNS) tumours are divided into four tumour types – grades 1 to 4. These grades are based on cells examined using a microscope as well as genetic and epigenetic changes that are discovered during molecular testing in a laboratory.

Grade 1 glioma (low-grade glioma): Grade 1 gliomas are usually occur in children and teenagers. They are the most slow-growing (low-grade) form of glioma brain tumour and carry the longest prognosis. The most common form of low-grade glioma is a pilocytic astrocytoma, which rarely progresses to a higher grade and can sometimes be completely removed by surgery .

Grade 2 glioma (low-grade glioma): Grade 2 gliomas are more common in adults but can also occur in children and teenagers. They are initially a slow-growing (low-grade) form of brain tumour but have a tendency to progress to a higher grade over time – usually a number of years. As prognosis varies between individuals, patients’ clinicians are best-placed to advise how long this process may take.

Oligodendroglioma and oligoastrocytomas tumours are often classified as grade 2 gliomas.

Grade 2 astrocytomas are sometimes also referred to as diffuse astrocytomas because they infiltrate through the brain. This is due to the nature of astrocytoma cells, which reach between and around the neurons.

Grade 3 glioma (anaplastic glioma): Anaplastic means that the glioma brain tumour cells are dividing rapidly . Anaplastic gliomas, also called grade 3 gliomas, are classed as a malignant form of brain cancer. They often spread to other parts of the brain and are more challenging to treat than low-grade gliomas.

Grade 4 glioma (glioblastoma multiforme): A glioblastoma multiforme (GBM) brain tumour may have developed from a lower grade of glioma, but the name changes once it is classified as high-grade. This is to reflect the fact that a grade 4 glioma usually has a mixture of cancerous cells within it, primarily astrocytoma and oligodendroglioma cells.

You can read more about glioblastoma multiforme (GBM) tumours here.

What symptoms are associated with glioma brain tumours?

Due to the range of different types of glioma brain tumours, we recommend you visit our brain tumour symptoms page.

What causes a glioma brain tumour?

We need to fund more research in order to understand how gliomas and other brain tumours are caused.

No single, definitive cause has yet been identified for brain tumours. Some risk factors have been identified, but due to the complex and unique health history for each patient, scientists are still unable to answer this fundamental question.

When glial cells form a glioma tumour, damage can be seen in the DNA and for example they no longer undergo apoptosis, which means programmed or purposeful cell death.

Discover more about risk factors for glioma and other brain tumours.

How are gliomas treated?

Find out here how gliomas and other brain tumours are treated.

The treatment of gliomas, including glioblastoma multiforme (GBM), involves a multidisciplinary approach that may include surgery, radiation therapy, and chemotherapy. The specific treatment plan depends on factors such as the type and grade of the glioma, its location within the brain, and the overall health of the patient. Here is an overview of the primary treatment modalities:

Surgery:

Objective: The goal of surgery is to remove as much of the tumour as possible while preserving essential brain functions.
Resection: In some cases, a neurosurgeon may perform a resection to cut out the tumour. However, complete removal might be challenging, especially if the tumour is located in critical or inaccessible areas of the brain.

Radiation Therapy:

Purpose: Radiation therapy is often used to target remaining tumour cells after surgery or to treat tumours that cannot be surgically removed.
External Beam Radiation: High-energy beams are directed at the tumour from outside the body.
Brachytherapy: Radioactive material is placed directly into or near the tumour.
Chemotherapy:

Adjuvant Therapy: Chemotherapy may be used in addition to surgery and radiation as adjuvant therapy to target remaining cancer cells.
Temozolomide: This oral chemotherapy drug is commonly used in the treatment of glioblastoma.

Targeted Therapy:

Purpose: Targeted therapies aim to interfere with specific molecules involved in the growth and progression of cancer cells.
Bevacizumab: This anti-angiogenic drug may be used to inhibit the formation of new blood vessels that supply the tumour.
Immunotherapy:

Purpose: Immunotherapy is an evolving area of research aiming to harness the body's immune system to recognize and attack cancer cells.
Checkpoint Inhibitors: These drugs target immune checkpoints, enhancing the body's ability to mount an immune response against the tumour.
Clinical Trials:

Purpose: Participation in clinical trials may provide access to experimental treatments and contribute to the advancement of glioma research.
Novel Therapies: Ongoing research explores new drugs and treatment strategies to improve outcomes for patients with gliomas.
Supportive Care:

Symptom Management: Glioma treatment may have side effects, and supportive care is essential to manage symptoms such as pain, seizures, and neurological deficits.
Rehabilitation: Physical and occupational therapy may be employed to help patients regain or maintain functional abilities.
Follow-up Care:

Monitoring: Regular follow-up visits are crucial to monitor the patient's condition, assess treatment response, and address any emerging issues.
Imaging: Imaging studies, such as MRI or CT scans, are often used to monitor for tumour recurrence or progression.

What is molecular testing and what do molecular markers of glioma brain tumours mean?

Current UK guidelines for the classification of gliomas defined by NICE (the National Institute for Clinical Excellence) state that tumours should also be tested for various molecular markers.

Find out more about causes of brain tumours

What is the survival rate for glioma?

The survival rate for glioma can vary widely depending on the specific type and grade of the tumour, as well as the individual's age, overall health, and other factors.

Glioma is a type of brain tumour that originates in the glial cells, which are the supportive cells in the brain. Gliomas are classified by grade, ranging from grade I (least aggressive) to grade IV (most aggressive).

According to the American Brain Tumour Association, the 5-year survival rate for glioma varies widely depending on the grade and other factors, but ranges from 5% to 95%. Specifically:

Grade I gliomas (such as pilocytic astrocytomas) generally have a very good prognosis, with a 5-year survival rate of around 95%.
Grade II gliomas (such as diffuse astrocytomas) have a 5-year survival rate of around 40-50%.
Grade III gliomas (such as anaplastic astrocytomas) have a 5-year survival rate of around 25-30%.
Grade IV gliomas (such as glioblastoma multiforme) are the most aggressive and have a 5-year survival rate of around 5-10%.

It's important to note that survival rates are statistical averages and do not necessarily reflect an individual's prognosis. Each person's situation is unique, and their specific prognosis will depend on a variety of factors. It's also important to work closely with a medical team and follow their recommended treatment plan.

Is glioma always fatal?

Gliomas are a type of brain tumour that can vary in their aggressiveness, and not all gliomas are fatal. However, some gliomas are highly aggressive and can be difficult to treat, which can make them more likely to be fatal.

The prognosis for gliomas depends on several factors, including the specific type and grade of the tumour, its location, the age and overall health of the patient, and the response to treatment. Some types of gliomas, such as low-grade gliomas (such as pilocytic astrocytomas) or certain types of oligodendrogliomas, may have a relatively good prognosis and may be treated successfully with surgery and/or radiation therapy.

Can glioma be cured?

The ability to cure a glioma depends on several factors, including the type and grade of the tumour, its location, and the patient's age and overall health. 

Low-grade gliomas (such as pilocytic astrocytomas) and some types of oligodendrogliomas may be more curable than other types of gliomas. In some cases, these tumours may be removed surgically and may not require further treatment.

However, high-grade gliomas (such as glioblastoma multiforme) are more difficult to cure. These tumours tend to grow quickly and spread aggressively, and they may be resistant to treatment. While surgery, radiation therapy, and chemotherapy can help slow the growth of these tumours and prolong survival, they are generally not curative.

Find out more about brain tumour treatments

What is an optic nerve glioma?

An optic nerve glioma is a slow-growing tumour that originates from glial cells along the optic nerve, the pathway connecting the eye to the brain. Primarily diagnosed in children, especially those with neurofibromatosis type 1 (NF1), symptoms may include peripheral vision loss and optic disc swelling. Diagnosis involves eye exams and imaging studies, and treatment varies based on tumour size and symptoms. Small, asymptomatic tumours may be monitored, while larger ones may require surgery, radiation, or chemotherapy. Early detection and a multidisciplinary approach are crucial for managing optic nerve gliomas and preserving vision.

How can we find a cure for gliomas?

Research we are funding across all of our Centres of Excellence will help lead towards finding a cure for glioma brain tumours.

Pioneering research at our Brain Tumour Research Centre of Excellence at Queen Mary University of London is focused on using GBM stem cells to help develop unique, patient-specific treatments.

Our team at the University of Plymouth Low-Grade Brain Tumour Centre of Excellence are researching a range of mutations in brain tumour cells that initiate tumour progression and drive growth, transforming slow-growing low-grade gliomas into high-grade gliomas. Their discoveries are designed to enable new treatments to be developed and tested in order to halt and hopefully reverse this process. The team are also testing combination therapies for low-grade brain tumours, designed to enhance the effectiveness of existing treatments.

The team of research and clinical experts at our Centre of Excellence at Imperial College, London, are part of a global collaboration looking at how the ketogenic diet can influence glioma metabolism and help in the effective treatment and management of living with this brain tumour.

Scientists at our Centre of Excellence in the University of Portsmouth are looking at mitochondria in glioblastomas, exploring ways to ‘shut down’ these ‘batteries’ that supply energy to the brain tumours.

We also fund BRAIN UK at Southampton University, the country’s only national tissue bank registry providing crucial access to brain tumour samples for researchers from all clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, and an essential component in the fight to find a cure for glioma brain tumours.

 

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