Glioma

What is glioma?

A glioma is a type of brain tumor that starts in glial cells. Glial cells are the support cells of the brain and spinal cord. They surround nerve cells (neurons), hold them in place, supply them with nutrients and help protect them. When glial cells begin to grow and divide in an uncontrolled way, they can form a mass called a glioma brain tumor.

Gliomas are among the most common tumors that begin in the brain itself, rather than spreading to the brain from another part of the body. Doctors call tumors that start in the brain "primary" brain tumors. Gliomas can occur at any age. Some types are more common in children, while others are seen more often in adults, and the risk of certain types tends to rise with age.

Not all gliomas behave the same way. Some grow slowly over many years and cause few problems for a long time. Others grow quickly and can be life-threatening. Doctors describe this difference using a grading system, explained in more detail below. Because gliomas grow within brain tissue, even a slow-growing tumor can cause symptoms depending on where it sits and how much pressure it puts on nearby structures.

Types of glioma

Gliomas are named after the type of glial cell they most closely resemble. The main types of glioma include:

• Astrocytoma – begins in star-shaped cells called astrocytes. Astrocytomas range from slow-growing to very aggressive.
• Glioblastoma – the most aggressive form of astrocytoma. It is classified as grade 4, the highest grade.
• Oligodendroglioma – begins in oligodendrocytes, cells that make the insulating layer around nerve fibers. These tumors often grow more slowly.
• Ependymoma – begins in ependymal cells, which line the fluid-filled spaces in the brain and the center of the spinal cord.
• Mixed or other gliomas – some tumors show features of more than one cell type, and doctors now also classify gliomas by specific genetic changes found in the tumor cells.

Doctors also assign a grade from 1 to 4. Grade 1 tumors grow slowly and are the least aggressive. Grade 4 tumors grow rapidly and spread into surrounding brain tissue. The grade, together with genetic testing of the tumor, helps guide decisions about treatment.

Glioma symptoms

Glioma symptoms vary widely. They depend on where the tumor is in the brain, how large it is, how fast it is growing and whether it increases pressure inside the skull. Some people notice symptoms suddenly, while others develop them gradually over months or years.

Common glioma symptoms include:

• Headaches, especially headaches that are new, worsening, or worse in the morning
• Seizures (sudden electrical disturbances in the brain that can cause shaking, staring spells or loss of awareness)
• Nausea or vomiting, particularly with headache
• Weakness or numbness in an arm, leg or one side of the face
• Problems with balance or walking
• Difficulty speaking or understanding language
• Vision changes, such as blurred or double vision or loss of part of the visual field
• Memory problems or difficulty concentrating
• Changes in personality, mood or behavior
• Increasing drowsiness or confusion

How symptoms differ by type and grade

Slow-growing, lower-grade gliomas are often first noticed because of a seizure in a person who has never had one before. Because the tumor grows slowly, the brain may adapt to it, and other symptoms can be mild or absent for a long time. In contrast, fast-growing, higher-grade gliomas such as glioblastoma may cause symptoms that appear and worsen over weeks. These often include headache, nausea, weakness and changes in thinking, because the tumor and the swelling around it increase pressure inside the skull.

Location also matters. A tumor near the areas that control movement may cause weakness on one side of the body. One near language areas may cause trouble finding words. A tumor in the cerebellum, at the back of the brain, may affect coordination. Gliomas in the spinal cord may cause back pain, weakness or numbness in the limbs, or problems with bladder or bowel control.

Many of these symptoms can also be caused by conditions that are far more common than a brain tumor. Having one or more of them does not mean a person has a glioma, but persistent or worsening symptoms should be evaluated by a doctor.

Causes and risk factors

In most cases, doctors do not know exactly what causes a glioma. The tumor develops when glial cells acquire changes (mutations) in their DNA that allow them to grow and divide without the usual controls. These changes usually happen during a person's lifetime rather than being inherited, and what triggers them is often unclear.

Known or suspected risk factors include:

• Age – gliomas can occur at any age, but the risk of many types increases as people get older. Some types, such as certain ependymomas and low-grade astrocytomas, are more common in children.
• Previous radiation to the head – people who received radiation therapy to the head, for example to treat another cancer during childhood, have a higher-than-average risk of developing a glioma later in life.
• Inherited genetic syndromes – a small number of gliomas occur in people with rare inherited conditions such as neurofibromatosis type 1, Li-Fraumeni syndrome, Lynch syndrome or tuberous sclerosis.
• Family history – having a close relative with a glioma may slightly increase risk, although most people with a glioma have no family history of the disease.
• Sex – gliomas overall are somewhat more common in men than in women.

Many factors have been studied without clear evidence that they cause glioma, including mobile phone use, head injury, diet and exposure to household chemicals. Current research has not confirmed these as causes. Gliomas are not contagious and cannot be passed from one person to another.

Diagnosis

Diagnosing a glioma usually begins when a person sees a doctor about symptoms such as headaches, seizures or weakness. The doctor takes a detailed medical history and performs a neurological examination. This involves checking vision, hearing, balance, coordination, strength, reflexes and thinking. Problems in one or more of these areas may point to which part of the brain is affected.

The main tests used to confirm a glioma include:

• Magnetic resonance imaging (MRI) – the most important imaging test for brain tumors. MRI uses magnetic fields and radio waves to create detailed pictures of the brain. A contrast dye is often injected into a vein to make the tumor easier to see. Special MRI techniques can also show brain activity, blood flow and the chemical makeup of the tumor.
• Computed tomography (CT) scan – uses X-rays to produce cross-sectional images. CT is often used first in emergency settings because it is quick, and it can show bleeding or swelling.
• Biopsy – the removal of a small piece of tumor tissue so it can be examined under a microscope. A biopsy may be done through a small hole in the skull using image guidance, or as part of surgery to remove the tumor. A biopsy is the only way to confirm the exact type and grade of a glioma.
• Molecular and genetic testing – laboratory tests on the tumor tissue look for specific changes in genes and proteins, such as IDH mutations, 1p/19q codeletion and MGMT promoter methylation. These terms describe particular alterations in the tumor's DNA. They are now a standard part of classifying gliomas and help predict how a tumor may behave and respond to treatment.

In some situations, doctors may also order an electroencephalogram (EEG), which records the brain's electrical activity and is used to evaluate seizures, or a lumbar puncture (spinal tap) to examine the fluid around the brain and spinal cord. Vision and hearing tests may be used if those functions are affected.

The final diagnosis combines what the tumor looks like under the microscope, its genetic features and its appearance on imaging. This detailed classification is what allows the treatment team to recommend an approach suited to the individual tumor.

Glioma treatment options

Glioma treatment depends on the type and grade of the tumor, its location, its genetic features, the person's age and general health, and the symptoms it is causing. Treatment is usually planned by a team that includes neurosurgeons, neuro-oncologists (cancer doctors who specialize in the nervous system), radiation oncologists, pathologists, nurses and rehabilitation specialists. At Acibadem, gliomas are managed through the neurosurgery and oncology departments working together.

Observation

For some small, slow-growing gliomas that are not causing significant symptoms, doctors may recommend regular monitoring with MRI scans rather than immediate treatment. This is sometimes called watchful waiting or active surveillance. If the tumor grows or symptoms develop, treatment can then be started.

Surgery

Surgery is often the first treatment for gliomas that can be safely reached. The goals are to remove as much of the tumor as possible, to obtain tissue for diagnosis and to relieve pressure in the brain. Because gliomas grow into surrounding brain tissue, it is often not possible to remove every tumor cell without damaging important areas. Surgeons use tools such as image guidance, intraoperative MRI, brain mapping and, in some cases, awake surgery to remove tumor while protecting functions like speech and movement. Removing even part of a tumor can reduce symptoms and may help other treatments work better. More information about surgical care for brain tumors is available from the neurosurgery department.

Radiation therapy

Radiation therapy uses high-energy beams to damage tumor cells so they cannot grow. It is commonly used after surgery for higher-grade gliomas, for tumors that cannot be removed surgically, or when tumor remains after an operation. Treatment is usually delivered in daily sessions over several weeks. Modern techniques aim the beams precisely to limit exposure to healthy brain tissue. Side effects may include tiredness, hair loss in the treated area, skin irritation and, in some cases, longer-term effects on memory or thinking.

Chemotherapy

Chemotherapy uses drugs to kill rapidly dividing cells. For many gliomas, the most commonly used drug is temozolomide, which is taken by mouth. It is often given during and after radiation therapy for high-grade tumors and may also be used for some lower-grade gliomas. Other chemotherapy drugs or combinations may be recommended depending on the tumor type and genetic profile. Side effects can include nausea, fatigue and a reduced ability to fight infection.

Targeted therapy and newer approaches

Targeted therapies are drugs designed to act on specific genetic changes in tumor cells. For certain gliomas with particular mutations, targeted drugs may be an option. Other approaches, such as tumor treating fields (a device worn on the scalp that delivers low-intensity electrical fields), immunotherapy and clinical trials of new treatments, may be discussed depending on the situation. Your doctor may talk with you about whether a clinical trial is appropriate.

Medications for symptoms

Medications are often used alongside other treatments. Corticosteroids reduce swelling around the tumor and can quickly ease headaches and other pressure-related symptoms. Anti-seizure medicines help control seizures. Pain relievers, anti-nausea drugs and medicines for mood or sleep may also be prescribed as needed.

Rehabilitation and supportive care

A glioma or its treatment can affect movement, speech, thinking and daily activities. Rehabilitation aims to restore or compensate for these functions. Physical therapy helps with strength and balance, occupational therapy focuses on everyday tasks, and speech and language therapy addresses communication and swallowing. Neuropsychologists may help with memory and attention. Palliative care, which focuses on relieving symptoms and improving quality of life, can be offered at any stage of illness and is not limited to end-of-life care.

Living with glioma and outlook

Hearing a diagnosis of glioma is difficult, and it is normal to feel shocked, anxious or overwhelmed. The outlook varies enormously from person to person. Factors that influence it include the tumor type and grade, its genetic features, how much of it could be removed, its location, the person's age and overall health, and how the tumor responds to treatment.

In general, lower-grade gliomas grow slowly, and many people live for many years after diagnosis, although these tumors may eventually change into a higher grade. Higher-grade gliomas, particularly glioblastoma, are more aggressive and harder to control, and they often return after treatment. Because of this range, general statistics about the glioma survival rate can be misleading for any one individual. Your medical team is best placed to discuss what is known about your specific tumor and what the likely course may be.

Living with a glioma often means ongoing follow-up with regular MRI scans to watch for regrowth, as well as managing symptoms and treatment side effects over time. Many people continue to work, drive (subject to local rules, especially after seizures), and take part in family and social life, sometimes with adjustments. Fatigue, memory changes and mood changes are common and can often be helped with rehabilitation, counseling and medication.

Emotional and practical support matters as much as medical care. Counseling, support groups and social work services can help patients and families cope with uncertainty, make decisions and plan ahead. Caregivers also need support, as caring for someone with a brain tumor can be physically and emotionally demanding.

Frequently asked questions

What is the difference between glioma vs glioblastoma?

Glioma is the broad name for any tumor that starts in glial cells. Glioblastoma is one specific type of glioma. It is the most aggressive form of astrocytoma and is classified as grade 4, the highest grade. In other words, every glioblastoma is a glioma, but not every glioma is a glioblastoma. Many gliomas are lower grade and grow far more slowly than glioblastoma.

What are the first glioma symptoms people usually notice?

There is no single first symptom. Some people first experience a seizure, which is especially common with slow-growing gliomas. Others notice headaches that are new or different from their usual headaches, particularly if they are worse in the morning or accompanied by nausea. Weakness, numbness, speech difficulty, vision changes or changes in personality can also be early signs, depending on the tumor's location.

Is a glioma brain tumor always cancer?

Gliomas are generally considered malignant (cancerous) brain tumors, although they range from slow-growing, less aggressive forms to fast-growing, highly aggressive forms. Even lower-grade gliomas are usually treated as serious because they grow into surrounding brain tissue and can progress to a higher grade over time. Gliomas rarely spread outside the brain and spinal cord.

What does the glioma survival rate depend on?

Survival depends on many factors, including the type and grade of the glioma, specific genetic features of the tumor cells, the person's age and general health, the tumor's location and how much of it could be safely removed. Lower-grade gliomas are generally associated with longer survival than high-grade gliomas such as glioblastoma. Published statistics are averages from large groups and cannot predict what will happen to any one person.

Can glioma be cured?

Some low-grade gliomas, particularly certain grade 1 tumors in children, may be cured if they can be completely removed by surgery. For most other gliomas, treatment aims to control the tumor for as long as possible and to preserve quality of life, because tumor cells that have grown into surrounding brain tissue often cannot all be removed. Research into new treatments is ongoing, and outcomes vary with tumor type and individual circumstances.

What are the main types of glioma?

The main types are astrocytoma (including glioblastoma), oligodendroglioma and ependymoma, named after the glial cell they resemble. Doctors also classify gliomas by grade, from 1 to 4, and increasingly by genetic changes such as IDH mutation status. This combined classification helps predict how the tumor is likely to behave and which glioma treatment approaches may be most appropriate.

Does glioma treatment always involve surgery?

Not always. Surgery is a common first step when the tumor can be reached safely, but some gliomas are located in areas where an operation would cause serious harm. In these cases, a biopsy may be taken for diagnosis and treatment may rely on radiation therapy, chemotherapy or other drugs. For some small, slow-growing tumors without symptoms, doctors may recommend monitoring with regular scans before any treatment.

When to see a doctor

Many symptoms linked to glioma are also caused by common, less serious conditions. However, persistent, unexplained or worsening neurological symptoms should always be evaluated by a doctor, who can decide whether imaging or referral to a specialist is needed. If you have already been diagnosed with a glioma, follow the monitoring plan your team has set out and report any new or changing symptoms promptly.

Seek emergency medical care right away if you or someone you are with experiences any of the following red-flag signs:

• A seizure in someone who has never had one before, or a seizure lasting more than a few minutes
• A sudden, severe headache unlike any headache experienced before
• Sudden weakness, numbness or paralysis of the face, arm or leg, especially on one side
• Sudden difficulty speaking, understanding speech or confusion
• Sudden loss of vision or double vision
• Severe headache with repeated vomiting, drowsiness or difficulty staying awake
• Loss of consciousness or unresponsiveness
• Sudden loss of balance or inability to walk

These signs may indicate raised pressure inside the skull, bleeding, a stroke or another serious condition, all of which require urgent assessment.