36 Brain Tumors

Brain Tumors – What are they?

Both benign and malignant brain tumors can become life-threatening due to brain tissue compression.  The increased intracranial pressure that occurs with a growing tumor in the brain can lead to local hypoxia.  Brain cancer is one of the most common childhood cancers.  Overall, brain cancer is less metastatic than other cancers, but is highly fatal.

Brain cancer typically arises when DNA mutations occur in one of the four types of neuroglial cells.

1. Astrocytes, are primarily responsible for structural and physiological support of neurons.  In addition to creating scaffolding as well as the blood-brain barrier, astrocytes play a key role in the recycling of neurotransmitters and neuron maintenance. Cancerous astrocytes can give rise to glioblastomas and astrocytomas (two of the most common types of brain cancer).
2. Ependymal cells, line the ventricles of the brain as well as the central canal of the spinal cord playing a role in the constant production and circulation of cerebrospinal fluid.
3. Microglial cells are small macrophages that are required for protecting against pathogens and removing cellular debris.
4. Oligodendrocytes are myelin sheath cells wrap around neuron axons and serve to increase the conduction velocity of action potentials.

Brain cancer can also be caused by cancerous cells arising in the meninges (i.e., dura mater, arachnoid mater, or pia mater).  Cancers within the meninges are called meningioma.

Brain Cancer – Risk Factors and Prevention Strategies

Risk factors for brain cancers include genetic susceptibilities (i.e., family history), immunosuppression, and exposure to carcinogens.

Prevention strategies include: limiting one’s exposure to ionizing radiation and other carcinogens as well as viruses that can be immunosuppressive (e.g., HIV).

Brain Cancer – Signs and Symptoms

Signs and symptoms can include a range of different symptoms such as headaches, nausea, cognitive problems, dysphagia, ataxia, fatigue, paresthesia, muscle weakness, changes in behaviour, loss of consciousness, and/or problems with hearing, vision, coordination, balance, or memory.

Brain Cancer – Diagnosis

Often, imaging (e.g., MRI, CT scan, PET scan) and biopsies (when possible) are used to assist in the diagnosis of brain cancer.  Biopsy or collection of cells that may be present in cerebrospinal fluid through lumbar puncture are strategies used that allow for the collected cells to be analyzed under the microscope which is the most definitive way to diagnose brain cancer.  At times neurological exams (e.g., checking vision, hearing, reflexes, motor coordination and strength) are also used to determine what areas of the brain are affected (though are not diagnostic on their own).

Brain Cancer – Treatment

Treatments include surgery (when possible), chemotherapy, radiation therapy and immunotherapy.