If you are healthy enough to tolerate it, surgery is the first option to be considered when approaching the treatment of
brain tumors. The goals of surgery depend in large part on what type of tumor is suspected based on the history, clinical findings, and radiographic picture. The hope is always that the entire tumor can be removed, although with most tumor types residual tumor will remain after surgery. Many studies have demonstrated that greater resection will result in better outcomes. If only a small amount of tumor can be safely removed, most surgeons prefer to take a biopsy
only to identify tumor type and then nonoperative therapies (
radiation) are used.
Surgical procedures include:
Craniotomy means "cutting into the head." All conventional brain surgery begins this way. The opening will be as close to the tumor as possible. Some tumors are best approached through the nose or the top of the neck. Most approaches go through the scalp and the skull to expose the upper part of the brain (the cortex).
Description of the Procedure:
The skin, usually the scalp, is shaved and an incision is made. Then a piece of the skull bone is removed to expose the brain. In select circumstances, once the brain is exposed, the surgeon may do some mapping to identify functional areas of the brain. The tumor will be exposed, isolated from normal brain, and removed. The surgery may take many hours.
A biopsy is a sampling of tissue from a surgery. The doctor examines the biopsy to make a diagnosis. Biopsy tissue can be obtained via a craniotomy, or it can be obtained through a smaller surgery called a stereotactic biopsy. The surgeon drills a small hole through the skull. She then uses imaging to guide a needle into the brain and tumor. A sample of tissue is removed. The decision of whether to proceed with a biopsy or a larger craniotomy will be made by your team.
Pressure inside the skull is a critical factor, since the brain is very sensitive to pressure changes. Increasing pressure rapidly impairs brain function and can be potentially fatal. If this happens, it can be treated with a relatively simple procedure known as a shunt.
In a manner similar to taking a biopsy, a small hole is made in the skull. Through this hole, a tube is inserted into one of the fluid-filled spaces inside the brain. The other end of the tube is passed under the skin from the head to the trunk where it drains fluid into the heart or abdomen. A one-way valve in the tube prevents back flow into the brain.
A potential problem with a shunt is that in moving fluid from the brain to the lower portions of the body (to relieve pressure in the brain), the surgeon may unwittingly be moving the brain tumor cells along with the fluid. This is a risk the patient and surgeon must discuss prior to the placement of a shunt.
Operating microscopes are commonly used during neurosurgery. Magnification greatly increases the precision with which an operation can be done.
The surgeon may need to know precisely what function is performed by parts of the brain near the surgical site. There are several ways to "map" your brain. Some are used during surgery; others do not require opening the head. They may involve:
- Stimulating brain tissue with tiny electrical currents
- Measuring brain waves as they are stimulated
- Using ultrasound probes inside or near brain structures
- Probing the brain with special computerized "wands”
techniques, such as functional MRI
- Positron emission tomography
(PET) or single photon emission computed tomography (SPECT)
- Magnetoencephalogram (MEG)—can be used to localize motor, sensory, and language function
- Thermal destruction instruments (eg, lasers)—can be placed in the exact spot to destroy tumor tissue
- Ultrasonic aspiration—breaks up tumor tissue and sucks it out of the brain; some tumors are most efficiently removed this way with less damage to normal brain tissue.
- Internal sources of radiation (Gliasite) or drugs (Gliadel)—can be administered within the tumor cavity
There is ongoing investigation evaluating other methods of locally administering radiation and chemotherapy. You can discuss these options with your team.
The blood supply to tumors can be identified by
angiography. This blood supply can then be shut off by introducing a variety of plugs. These plugs can block the artery from the inside, causing the tumor to die from lack of blood flow.