An in-depth report on the causes, diagnosis, and treatment of brain tumors.
Gliomas; Medulloblastoma
Surgery is usually the first step in treating most brain tumors. In some cases, however, such as most brain stem gliomas, it may be too dangerous to perform surgery. The object of most brain tumor surgeries is to remove or reduce as much of its bulk as possible. By reducing the size, other therapies, particularly radiotherapy, can be more effective. (Although there have been significant advances in brain surgeries, some experts argue that in high-grade gliomas extensive surgery may not improve survival rates at all and patients are best served by radiation therapy.)
The standard procedure is called craniotomy.
There are various surgical options for breaking down and removing the tumor. They include:
Relatively benign, grade I gliomas may be treated only by surgery. Some controversy exists over whether surgery for low-grade astrocytomas improves survival, although insufficient research has been conducted to prove its benefits for these gliomas. Most malignant tumors require additional treatments, including repeat surgery.
The surgeon's skill in removing the tumor as completely as possible is critical to survival. No one should be shy about asking the surgeon the number of similar procedures they have performed. (Asking for complication rates may not be useful, since a very experienced surgeon might operate on many high-risk patients.)
In most cancers outside the brain, surgical removal of a tumor usually involves taking out surrounding healthy tissue to be sure all cancer cells are gone. In the brain, however, removing healthy nearby nerve tissue can be as disastrous for the patient as the cancer itself. Special techniques have been developed to allow maximum removal of tumors while protecting healthy brain cells.
Stereotaxy. Stereotaxy has become a useful adjunct to both surgery (stereotactic surgery) and radiotherapy (stereotactic radiotherapy).
Cortical Localization. Cortical localization, or stimulation, uses a probe that passes a tiny electrical current to delicately stimulate a specific area of the brain. This produces a visible response of the body part (such as a twitch in a leg), which the stimulated region of the brain controls. The surgeon then knows to avoid those areas during the operation.
Image-Guided Surgery. Image guided surgery uses a three-dimensional picture of the patient's brain derived from computed tomography (CT) or magnetic resonance imaging (MRI) scans. An advanced technique called high-field interventional MR imaging (iMRI) is particularly accurate in identifying the tumor, but it is not widely available. The image, with various views of the brain, is displayed on a monitor in the operating room. During surgery, as the surgeon's instrument touches a part of the brain, a camera sends the image to a computer, which calculates the position of the surgical tool and displays it in its proper location on the 3-D image. The surgeon then can look at the monitor and see what structures to avoid.
Magnetic-Tipped Catheters. Neurosurgeons are investigating a technique in which external magnetic fields direct a magnet-tipped flexible catheter to the tumor site through a path that avoids harming certain important areas of the brain.
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