Brain tumors - gliomas

What are gliomas? Gliomas are brain tumors associated with the three types of glial cells in the brain, which include astrocytes, oligodendrocytes and the ependymal cells. Glial cells make up the supportive tissue of the brain and, unlike neurons, don’t conduct electrical impulses.

If left untreated, any type of glioma may grow and press on other structures within the brain.

Pressure on the brain can be harmful as it forces the brain against the skull, causing damage to the brain and hampering its ability to function properly. This reduced function can lead to long-lasting brain damage or, if left untreated, death. The symptoms of glioma depend on the size, grade and location of the glioma, but can include:

• vision changes
• abnormal eye movements

Glial cells make up the supportive tissue of the brain. The 3 types of glial cell are:

• – these cells regulate brain activity
• control the movement of blood to the brain. They are star-shaped
• hence their name ‘astro’

– these cells produce the myelin sheath. This protective sheath surrounds the nerve fibers in the brain and spinal cord, and helps conduct messages along the nerves. – these cells line the internal (ventricular) walls of the fluid spaces located inside the brain canal and spinal cord.

Gliomas refer to tumors that can originate in glial cells and include:

• – tumors that originate in the astrocytes
• make up about 25 to 30 per cent of all gliomas. Astrocytomas can occur anywhere within the brain
• are often cystic (cyst-forming). – tumors of the oligodendrocytes
• which can occur anywhere there is myelin sheath

This type of tumor is most common in men between 35 to 40 years of age. – usually benign and lower grade tumors.

However, they can sometimes grow and spread rapidly via the pathways that carry the cerebrospinal fluid (CSF).

Ependymomas are more common in adolescent males#

Gliomas are graded according to how malignant (cancerous) they are. Classifications developed by the World Health Organization (WHO) are generally used. These classifications are:

• Endothelial or vascular proliferation – the speed of cell growth
• production of new blood vessels Presence of necrosis – whether brain cells are dying

Infiltrating gliomas are graded according to the following characteristics as seen under the microscope: – slow-growing tumors with slowly dividing cells. There is no significant necrosis (cell death) or vascular proliferation (increased blood vessel growth – cancerous tumors create extra blood vessels). – slow-growing tumors with more rapidly dividing cells.

There is no significant necrosis or vascular proliferation#

– these brain tumors can arise from lower grade gliomas and may develop further into higher grade tumors. They are described as having focal or diffuse areas of high cell division and, therefore, show many dividing nuclei (the small sac within the cell that contains the DNA). – these tumors have similar characteristics to grade III gliomas, but have a higher incidence of vascular proliferation and necrosis.

This tumor has an average survival time of only around 12 months. The range of tests used to diagnose glioma include:

• biopsy of the suspect tissue
• collected during brain surgery. Treatment options for gliomas can include: – a craniotomy is a procedure performed by a neurosurgeon

A hole is cut into the skull in order to provide access to the brain. This allows a biopsy of the glioma and the opportunity to remove some of the tumor at the same time.

After the operation is finished, the bone is replaced, and the muscle and skin are stitched.

– small, precise doses of radiation are used to target and destroy cancer cells. – the use of cancer-killing drugs.

In brain tumors, all 3 treatments are often in combination#

If a glioma has been diagnosed in its later stages, the cancer may have spread to the point where a cure is no longer possible.

Treatment then focuses on improving quality of life by relieving the symptoms. This is called ‘palliative’ treatment and may include using medications to relieve pain, nausea and vomiting. Symptoms of gliomas headaches nausea and vomiting drowsiness seizures changes in personality memory loss changes in speech weakness or loss of feeling in limbs walking difficulties Glial cells explained Astrocytes Oligodendrocytes Ependymal cells Gliomas explained Astrocytomas Oligodendrogliomas Ependymomas Gliomas are graded Degree of differentiation – how different the cell looks under a microscope from normal cells Cellularity or cell division – how fast the tumor grows Glioma grades explained Grade I Grade II Anaplastic grade III Glioblastoma multiforme (GBM) grade IV Diagnosis of gliomas physical examination medical history CT scan MRI scan Treatment for gliomas Surgery Radiotherapy Chemotherapy When a cure isn’t possible

Where to get help#

Key Points#

• This type of tumor is most common in men between 35 to 40 years of age
• Ependymomas are more common in adolescent males
• Treatment options for gliomas can include: – a craniotomy is a procedure performed by a neurosurgeon
• In brain tumors, all 3 treatments are often in combination
• Treatment then focuses on improving quality of life by relieving the symptoms