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Nervous System Tumors

Treatment

Physician developed and monitored.

Original source: www.neurologychannel.com
Original Date of Publication: 02 Jan 2000
Reviewed by: Stanley J. Swierzewski, III, M.D.
Last Reviewed: 04 Dec 2007

Home » Nervous System Tumors » Treatment

Treatment
Treatment for brain tumors usually involves a combination of surgery, radiation and chemotherapy. The first goal of treatment is to remove as much of the tumor as possible, without damaging the surrounding normal brain tissue. Factors such as the patient's age, general health, occupation, and personal choice, all play a role in determining a course of treatment.

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Some nervous system tumors can be treated surgically and others cannot. Sometimes there are several different surgical procedures for a particular type of tumor. Sometimes a tumor can be treated with radiation alone, and does not need to be surgically removed.

In most cases, a multidisciplinary team of medical specialists work together to contribute to a patient's treatment.

Surgery
For patients undergoing brain tumor surgery, it is important to perform certain medical tests beforehand to provide the safest possible surgery. All patients should be in generally stable medical condition.

Patients over the age of 40 should have an EKG and chest x-ray, as well as several other tests to evaluate factors such as blood pressure and diabetes. If the patient has uncontrolled hypertension or diabetes, their blood exhibits anticoagulation, or they have active coronary ischemia, surgery usually is not done.

Surgery is used to diagnose and treat brain tumors. Complications occur in less than 5% of cases, and depend on the type of tumor andof cerebrospinal fluid.

Most types of surgery involve temporarily removing a section of the skull, opening the dura (outer membrane that covers the brain), and then removing the tumor and replacing the bone.

New surgical techniques include stereotactic biopsy or surgery that use computer guidance to exactly locate and either biopsy or remove the tumor, endoscopic surgery, laser surgery, and surgery under local anesthesia.

Stereotactic Surgery
The word stereotactic comes from Greek and Latin words meaning "three dimensions" and "to touch." This technique utilizes CT scan and MRI scan of the brain to find the exact location of the tumor. A special frame is placed on the patient's head and only a very small hole is drilled through the skull. Stereotactic surgery reduces the rates of complications normally associated with performing an open resection (cutting or removing a tumor) in the brain, which involves cutting a wide opening in the skull. With computer guidance, the neurosurgeon is able to operate very precisely.

Endoscopic Surgery
Endoscopic surgery is a type of surgery used to remove pituitary adenomas. In the past, pituitary adenomas were removed by making an incision in the mouth, beneath the upper lip, and then using a microscope to look up through the tissue to the base of the skull where the pituitary gland is located. With

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an endoscope, the tumor can be removed without any incision at all. Instead, the surgeon goes through the nose and is able to reach and remove a tumor in the pituitary gland through existing nasal channels. This procedure is less painful and has a quicker recovery time. Other tumors that are at the base of the skull can also be removed using endoscopic surgery.

Laser Surgery
The use of lasers (light amplification by stimulated emission of radiation) allows a surgeon to remove diseased tissue by aiming a beam of concentrated light on it rather than using a scalpel to cut it away. Laser surgery is often used following traditional surgery to remove any residual tumor tissue.

Surgery under Local Anesthesia
Surgery under local anesthesia involves the use of brain mapping techniques. A brain mapping technique that allow a surgeon to operate in sensitive areas of the brain, such as those that control motor function or speech. Small electrodes can be used to stimulate specific pathways so that the nerve response can be measured and a surgeon can determine the function of the nerve. The patient is awake during surgery.

Postoperative Care
Postoperative care includes drug therapy with corticosteroids, histamine inhibitors (blocking stomach acid), and antiepileptics. Sometimes patients may need to visit a postoperative rehabilitation facility. Corticosteroids (dexamethasone and Decadron) help reduce swelling and can relieve various postoperative neurological effects.

Radiation Therapy
Most malignant brain tumors are treated with external-beam radiation even if the entire primary tumor is surgically removed, because often there are hidden tumor cells still left in the brain tissue.

For benign tumors, radiation is usually applied when the entire primary tumor cannot be surgically removed.

For malignant tumors, radiation more than doubles the survival rate for patients with anaplastic astrocytomas and glioblasoma multiformes, and it can prolong survival for patients with low-grade gliomas.

External Beam Radiation
External beam radiation is the traditional form of radiation therapy. It delivers radiation from outside of the body, usually a couple of weeks following surgery. It is typically applied at regular intervals for several weeks.

Hyperfractionation is a modified form of external beam radiation that involves applying less intense but more frequent doses of radiation, to which some patients respond more readily.

New Types of Radiation Therapy: Stereotactic Techniques
New types of radiation that are being used to treat brain tumors include stereotactic radiosurgery or radiotherapy, as well as brachytherapy. Stereotactic radiosurgery involves using focused radiation on a localized spot in a single dose. Even though it is called "radiosurgery," it does not involve actual surgery. A head frame, to which a CT or MRI scanner is attached, is attached to the patient's skull, and with the aid of the computer imaging, the radiologist is able to pinpoint the tumor and aim the radiation directly at it.

There are new stereotactic techniques that do not involve the use of the head frame. Often the radiation comes from several different directions and hits the tumor at various angles. The advantage of such localized radiation is that the surrounding, healthy tissue is left undestroyed.

It is often used in addition to external beam radiation, especially for malignant gliomas and mestastases that are in deep or sensitive areas of the brain where surgical removal is potentially dangerous. Some tumors, however, cannot be treated with such intense local radiation. The optic nerves are especially sensitive to radiation, so tumors near the optic nerves are better treated with several small doses rather than one big blast.

Stereotactic radiotherapy involves applying many small doses of radiation to a local spot, using the same imaging techniques that stereotactic radiosurgery requires. Brachytherapy involves implanting capsules that contain radioactive substances into the tumor.

There are various other radiation techniques, some of which are being used on an experimental basis. Other technologies include the use of medications or other compounds that may make tumor cells more sensitive to radiation.

Chemotherapy
Chemotherapy is not used for benign tumors and is not used for most malignant brain tumors, which are treated with radiation and/or surgery. The problem with chemotherapy is that it works by interrupting mitosis, the process of cell division. Many brain tumors are already slow-growing, so slowing down the process of their growth and division by chemotherapy does not do much good.

Another problem with using chemotherapy to treat brain tumors is finding or developing drugs that effectively cross through the blood-brain barrier and get to the place in the brain where they need to be in order to do any good.

One drug that has proved to be effective is BCNU. A new technique enables neurosurgeons to place a wafer soaked with BCNU into the surgical cavity after the tumor has been removed. By applying it directly into the tumorous region of the brain, side effects are limited and the drug has a more beneficial effect. Some tumors are treated by injecting drugs directly into the spinal fluid.

Overall, studies have shown that patients who receive chemotherapy for malignant tumors show improved survival compared to those who do not receive the chemotherapy. The effectiveness of chemotherapy depends on the tumor type (medulloblastomas, anaplastic astrocytomas and glioblastomas respond to varying degrees to certain drugs). Chemotherapy is often used in very young children to delay radiation therapy as long as possible. Some meniongiomas respond to anti-progesterone agents. Most mestastatic brain tumors do not respond to chemotherapy, although there are exceptions. With metastatic brain tumors, the best chemotherapy agent is usually the one that has been the most effective with the primary cancer.

There are many experimental treatments, ranging from novel chemotherapy agents to drug therapy to new ways of applying radiation. As with any serious illness, it is generally a good idea to get a second or third opinion and gather as much information as possible about treatment.