Brain Tumor Overview

Types

There are two general categories of brain tumors -- primary brain tumors and secondary brain tumors.
Primary Brain Tumors originate in the brain. The most common primary brain tumors originate in one of the supporting cells of the brain, the glia. These tumors are called gliomas.

Gliomas can be benign (non-cancerous) or malignant (cancerous). They can be subdivided into the following categories:
--Low-grade gliomas: slow-growing and the least malignant
--Intermediate grade gliomas (called anaplastic astrocytoma or anaplastic oligodendroglioma): more aggressive and grow more rapidly than low-grade tumors
--High-grade gliomas (including glioblastoma, malignant oligodendroglioma or gliosarcoma): highly malignant tumors that grow rapidly
Secondary Brain Tumors form when cancer cells from elsewhere in the body spread (metastasize) to the brain. These tumors are always malignant. Metastatic brain tumors originate most commonly from lung cancer, breast cancer or melanoma (a form of skin cancer), although any cancer can spread to the brain.

Symptoms
Headaches (usually upon awakening in the morning and getting better throughout the day
Seizures (in a person with no history of seizure activity)
Cognitive changes (changes in thought processing and other brain function)
Personality changes
Nausea and/or vomiting
Speech disturbance
Hearing loss (with or without dizziness)
Memory loss
Eye involvement such as double vision or loss of vision in one or both eyes

Diagnosis
Medical History and Neurological ExamA patient with a glioma is unaware of the tumor until symptoms develop. Symptoms normally prompt a visit to the primary physician, who then takes a detailed history and performs a physical examination, including a neurological exam.
MRI or CTIf further work-up is warranted, the most suitable test is a magnetic resonance image (MRI) of the head. This takes less than an hour and requires an intravenous injection to help see the tumor better. The advantage of the MRI is its ability to show the anatomic structures of the brain with greater clarity. A computerized tomography (CT) scan of the brain may also be used.
BiopsyDuring this procedure, samples of the mass are removed and studied by a neuropathologist who makes a definitive diagnosis. A mass is only presumed to be a tumor until a biopsy is performed.
Biopsies can be performed with great precision using stereotactic (brain-mapping) equipment. Even in situations where the tumor is in a difficult location and surgical removal is not advisable, a biopsy is usually recommended to obtain tissue for accurate diagnosis.
One disadvantage of biopsies is that the tissue sample might accidently miss certain parts of the mass containing relevant information about the aggressive nature of the tumor. Biopsies usually do not remove the whole tumor.

Treatment
Surgery

provides the most effective way to remove a tumor, to immediately relieve pressure in the brain, and to obtain an accurate neuropathologic assessment of the nature of the tumor. In most cases, surgery is planned. Only rare circumstances is it performed in an emergency.
In each case, the surgeon studies the anatomic details of the brain as seen on a good quality MRI or CT scan. The surgeon determines how to reach the mass and how to avoid damaging critical centers of brain function that might be adjacent to the mass.
Eventually, the surgeon must clearly and realistically explain to the patient the risks associated with the operation. Only then can a decision be made as to whether the mass should be removed. During this conversation, the surgeon and patient also should discuss which special tools will be used to minimize the risks of the operation. Special tools include intraoperative ultrasound, cortical brain mapping and image guided surgery. Image-guided surgery relies on computers and MRI pictures to guide the surgeon during the operation.
Radiation Therapy

If completely removed, a benign tumor (including low-grade glioma) does not require additional treatment. However, intermediate and high-grade gliomas do. This is because these tumors send tumor cells beyond the main visible mass and into the surrounding brain tissue. These cells are not visible on a MRI scan or to the surgeon in the operating room, and may be responsible for regrowth of tumor. For this reason, radiation therapy is recommended.
The standard form of radiation is delivered by a machine called a linear accelerator (LINAC) and is delivered to the area of the brain that surrounds the tumor. To minimize risk to normal parts of the brain, several strategies are used:
--Radiation is delivered in small daily amounts five days a week for six weeks
--Computer-based tools shape the radiation to match, or conform to, the shape of the tumor (this technique is called "conformal radiation therapy")

Radiosurgery refers to a single, high-dose radiation treatment to the brain. It can be performed with a LINAC machine or a "Gamma Knife" machine. The main advantage of radiosurgery is its ability to minimize the amount of radiation, and therefore damage, to surrounding brain tissue.
Metastatic brain tumors are generally treated with whole brain radiation over a period of two to three weeks. The entire brain is treated because tumor cells might exist in other parts of the brain.
Chemotherapy

There is a general misconception that chemotherapy is not useful in treating brain cancer. This is more likely to be true in elderly patients who have the more malignant forms of glioma. Several drugs are available, and they can be used alone or in combination.
Chemotherapy is usually given at the end of radiation therapy in cycles that repeat every four to six weeks for up to a year. The drugs are usually well-tolerated and rarely associated with the severe side effects that patients fear when they think of chemotherapy.