About Brain Cancer

The brain is a complex organ made up of specialized nerve and supportive tissues. The base of the brain is connected to the spinal cord, and together they form the central nervous system (CNS). Within the brain, we find the cerebrum (grey and white matter), the cerebellum, the hypothalamus, the pituitary gland, the midbrain, the medulla, and the brain stem. There are three ventricles (spaces) within the brain that produce cerebrospinal fluid (CSF) and provide cushioning for the brain. CSF also serves to lubricate and provide protection for the spinal cord within the spinal canal.

The CNS functions as the primary receiver, organizer, and distributor of information in the body, regulating all the major activities such as perception, cognition, attention, emotion, memory, and action. The brain is the body’s control centre. Different parts of the brain control movement, speech, emotions, consciousness, and internal body functions, such as heart rate, breathing, and body temperature. The brain is formed of 80 to 86 billion interconnected nerve cells or neurons, supported by glial cells such as oligodendrocytes and astrocytes that provide oxygen and nutrients to neurons as well as working to remove dead cells.

As treatments improve and patients live longer, the incidence of people living with metastatic brain tumours is increasing. Enhancing the quality of life for people with brain tumours requires access to quality specialty care, clinical trials, follow-up care and rehabilitative services.

 

Brain tumours are classified depending on the cells where they start and how fast they grow and spread. They are usually of two types: glioma or non-glioma tumours.

Gliomas

  • Glioblastoma (GBM)
    • Glioblastoma, or glioblastoma multiforme (GBM), is the most common high-grade tumour found in adults. It grows from the glial cells of the brain, which provide support and nutrients to neurons (brain cells). Glioblastomas are diffuse, meaning they extend in threadlike projections into the brain, and are aggressive tumours which grow and spread quickly. They are usually treated with surgery followed by chemotherapy and radiation; however, they tend to be resistant to treatment due to the different cell types that form this tumour. These tumours can be primary or secondary to an astrocytoma or oligodendroglioma, which are other types of gliomas that typically have better prognosis. [1]
    • This tumour is more common in people older than 45 years of age, and more common in men than in women.
  • Astrocytoma
    • Astrocytomas are the most common type of gliomas. They develop from the astrocyte cells, which are part of the supportive tissue of the brain. They occur in many parts of the brain, but particularly in the cerebrum. Astrocytomas are graded according to how fast and how extensively they grow. Grade I, or pilocytic astrocytomas, have the best prognosis. They are well contained and don’t tend to recur after surgery. Grade II, or diffuse astrocytomas, have irregular edges, making them difficult to remove completely; they can recur after treatment as a grade III. Grade III, or anaplastic astrocytomas, are more aggressive and tend to recur as grade IV tumours. These are also called glioblastomas and are the most aggressive and difficult to treat of gliomas. [2]
  • Ependymoma
    • Ependymomas are usually benign growths that start on the cells that line the ventricular system. This type of glioma is most common in children younger than three years of age, and in adults in their 40s and 50s. Ependymomas can be slow-growing tumours appearing within the cerebellum. In 10% to 15% of cases these tumours may block the spinal canal and cause a backup of cerebral spinal fluid (CSF) which can cause intracranial pressure. [3]

Non-Glioma Tumours

  • Germ Cell Tumours (GCTs)
    • These tumours tend to occur in the mid-section of the brain, and are more common in adolescents. Depending on the specific cells in which they start, they have different names: [4]
      • Choriocarcinoma
      • Embryonal carcinoma
      • Germinoma
      • Mixed germ cell tumour
      • Teratoma
      • Yolk sac tumour
  • Hemangioblastoma
    • This tumour grows out of the cells that line blood vessels. Hemangioblastoma may be associated to a genetic condition called Von Hippel-Lindau (VHL) syndrome, and occurs mostly in people in their 40s. [5]
  • Pineal Tumours
    • Pineal tumours grow out of the pineal gland, which is located in the centre of the brain mass, and is responsible for producing the hormone melatonin. These tumours tend to block the flow of CSF and produce hydrocephalus, which may require a shunt to be put in to reduce symptoms. [6]

 

Risk Factors

Signs & Symptoms

Prevention

 

[1] The Brain Tumour Charity, “Glioblastoma”, https://www.thebraintumourcharity.org/understanding-brain-tumours/types-of-brain-tumour-adult/glioblastoma/

[2] Brain Tumour Foundation of Canada, “Anaplastic Astrocytoma”, https://www.braintumour.ca/4872/anaplastic-astrocytoma

[3] Brain Tumour Foundation of Canada, “Ependymoma”, https://www.braintumour.ca/4885/ependymoma

[4] St. Jude Children’s Research Hospital, “Germ Cell Tumors”, https://www.stjude.org/disease/germ-cell-tumors-brain.html

[5] Brain Tumour Foundation of Canada, “Hemangioblastoma”, https://www.braintumour.ca/4933/hemangioblastoma

[6] Brain Tumour Foundation of Canada, “Pineal Tumours”, https://www.braintumour.ca/4931/pineal-tumours