Brain Cancer Basics

The words brain cancer evoke a dark and often confusing image. What does it really mean?

Ah, we nod. Brain tumor.

Let’s examine this topic, so we can understand what’s going on behind this challenging diagnosis.

Primary and Secondary Brain Cancer

• Primary brain cancer is the term used when the cancer begins in the brain. The brain is the primary site.
• Secondary Brain cancer or metastatic brain cancer is the term used when the primary site is elsewhere.

About Malignant Tumors of the Brain

Most brain tumors fall into categories: glial cell and non glial cell. Glial cells help to support the cells of the central nervous system so they work properly.

Types of glial cell cancers or Gliomas:

According to the American Cancer Society 77% of all malignant brain tumors are gliomas.

• Astrocytoma-An astrocyte is a star-shaped type of glial cell. These tumors are graded 1 to 4. Grade 1-pilocytic astrocytoma, Grade 2-diffuse astrocytoma, Grade 3-anaplastic astrocytoma, Grade 4-glioblastoma multiforme. (The lower the grade, the slower the tumor growth.) About 35% of brain tumors are reported to be astrocytomas. This type of brain tumor is usually seen in the cerebrum.
• Oligodendroglioma-A rare tumor that starts in cells called oligodendrocytes. Usually these tumors cannot be completely removed by surgery. They consist of 4% of brain tumors.
• Ependymoma-This type of tumor is found in cell ventricles or in the spinal cord. These consist of 2% of brain tumors. Ependymomas are usually diagnosed in children and young adults.
• Brain stem glioma-This type of tumor is found in the brain stem. The brain stem connects the rest of the brain to the spinal cord. They consist of less than 1% of adult brain tumors, usually diagnosed in children and middle aged adults.
• Ganglioglioma-This very rare tumor has both neurons and glial cells and has a high cure rate.

Non Glial Cell Tumors of the Brain:

• Medullosblastoma-The most common childhood brain tumor. A tumor that begins in the neurons of the cerebellum. A fast growing tumor that is responsive to radiation.
• Schwannoma-These tumors begin in the Schwann cell of the cranial nerves. These cells form the myelin that protect the nerves. They are often non malignant. They affect cells of the 8th cranial nerve which impacts balance and hearing.
• Craniopharyngioma-This tumor grows near the pituitary gland. Often it impacts the pituitary gland and the optic nerve. This tumor is usually diagnosed in infants and children.
• Germ cell-This tumor of the brain begins in the germ cell. It is most often diagnosed in persons under the age of thirty. The most common of these tumors in a germinoma which is an uncommon tumor.
• Pineal region tumor-A rare brain tumor that is found near the pineal gland. They consist of less than 1% of all primary brain tumors. They may include germinomas.
• Chordoma-A reoccurring, slow growth tumor that starts at the base of the skull or the end of the spine. More common in young adults and middle-aged adults.
• Meningioma-This tumor occurs in the meninges (the membrane that covers and protects the brain and spinal cord) This accounts for 20% of all primary brain tumors and is more commonly seen in women. A slow growing tumor, 85% are benign and can be removed by surgery. Some are malignant and reoccur, spreading to other parts of the body.

Causes of Brain Cancer:

What causes the gene mutations that form a cancerous cell and finally a tumor in the regions of the brain is still unknown.

Symptoms and Diagnosis:

Symptoms of brain tumors depend on the size of the tumor and what part of the brain they may be affecting.

The National Cancer Institute lists these common, but not all inclusive, symptoms of brain tumors. Of course these symptoms may be indicative of other medical conditions as well.

• Headaches
• Nausea or vomiting
• Changes in speech, vision, or hearing
• Problems balancing or walking
• Changes in mood, personality, or ability to concentrate
• Problems with memory
• Muscle jerking or twitching, or seizures
• Numbness or tingling in the arms or legs

Diagnosis is completed following a physical exam, neurological exam, imaging study (MRI, CT, x-ray) and may include a biopsy and spinal tap.

Treatment includes surgery, chemotherapy and/or radiation therapy.

Resources for Brain Cancer:

The American Cancer Society

The National Cancer Institute: What You Need to Know About Brain Tumors.

The Brain Tumor Society: Brain Tumor Action Week is May 4-10, 2008. One of the goals of the Brain Tumor Society is to provide patients with better therapies and treatment options.