Brain and spinal cord tumors are found in the tissue inside the skull or the bony spinal column which make up the central nervous system (CNS). A tumor is a mass of normal or abnormal cells that form a new growth or is present at birth (congenital). Tumors occur when genes that regulate cell growth become damaged or mutated, allowing cells to grow and divide out of control. When most normal cells grow, old or get damaged, they die, and new cells take their place. Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor. Tumors can form anywhere in the body.
Depending on its type, a growing tumor can kill healthy cells or disrupt their function. It can move or press on sensitive tissue and block the flow of blood and other fluid, causing pain and inflammation. A tumor can also block the normal flow of electricity in the brain or nerve signaling to and from the brain. Some tumors cause no trouble at all.
Brain tumors are classified as either benign (non-cancerous) or malignant (cancerous). Brain tumors are also classified as either primary or metastatic. When a brain tumor originates in the brain it is referred to as a primary brain tumor. Metastatic brain tumors begin as cancer elsewhere in the body and then spread to the brain.
Tumor Grades & Types
Primary brain tumors, tumors that originate in the brain, can be benign or malignant:
Benign brain tumors do not contain cancer cells:
- Usually, benign tumors can be removed, and they seldom grow back.
- Benign brain tumors usually have an obvious border or edge. Cells from benign tumors rarely invade tissues around them. They don't spread to other parts of the body. However, benign tumors can press on sensitive areas of the brain and cause serious health problems.
- Unlike benign tumors in most other parts of the body, benign brain tumors are sometimes life threatening.
- Benign brain tumors may become malignant.
Malignant brain tumors (also called brain cancer) contain cancer cells:
- Malignant brain tumors are generally more serious and often are a threat to life.
- They are likely to grow rapidly and crowd or invade the nearby healthy brain tissue.
- Cancer cells may break away from malignant brain tumors and spread to other parts of the brain or to the spinal cord. They rarely spread to other parts of the body.
Doctors group brain tumors by grade. The grade of a tumor refers to the way the cells look under a microscope:
- Grade I: The tissue is benign. The cells look nearly like normal brain cells, and they grow slowly.
- Grade II: The tissue is malignant. The cells look less like normal cells than do the cells in a Grade I tumor.
- Grade III: The malignant tissue has cells that look very different from normal cells. The abnormal cells are actively growing.
- Grade IV: The malignant tissue has cells that look most abnormal and tend to grow quickly.
Types of Primary Brain Tumors
There are many types of primary brain tumors. Primary brain tumors are named according to the type of cells or the part of the brain in which they begin. For example, most primary brain tumors begin in glial cells. This type of tumor is called a glioma.
Among adults, the most common types are:
- Meningioma: The tumor arises in the meninges. It can be grade I, II, or III. It's usually benign (grade I) and grows slowly.
- Oligodendroglioma: The tumor arises from cells that make the fatty substance that covers and protects nerves. It usually occurs in the cerebrum. It's most common in middle-aged adults. It can be grade II or III.
People with brain tumors have several treatment options. The options are surgery, radiation therapy, and chemotherapy. Many people get a combination of treatments.
The choice of treatment depends mainly on the following:
- The type and grade of brain tumor
- Its location in the brain
- Its size
- Your age and general health
Surgery is the usual first treatment for most brain tumors. However, sometimes surgery isn't possible. If the tumor is in the brain stem or certain other areas, the surgeon may not be able to remove the tumor without harming normal brain tissue. People who can't have surgery usually receive radiation therapy or other treatment.
Tumor location, size and type are considered when deciding the type of surgery to perform. Surgery to remove a lesion in the brain is called a Craniotomy. This is “open” brain surgery requiring removal of part of the skull bone to access the brain tissues.
Minimally invasive brain surgery may also be an option depending on your particular circumstances. Minimally invasive surgery is performed with an endoscope through the nose (endonasal) or through a tiny incision above the eye in order to remove the brain tumor. The endoscope is a special lighted instrument that sends images back to a computer for the surgeon to view internal structures and enables the surgeon to use tiny instruments within the endoscope to remove the tumor. Your healthcare team will discuss all options with you prior to surgery.