Brain Tumors

Definition

Primary brain tumors are cancers that arise in the brain rather than spreading to the brain from other parts of the body.

Description

Primary brain tumors make up about 1 percent of all cancers in the United States (13,000 cases a year) and cause roughly 2.5 percent of all cancer deaths.

These are the most common solid tumors in children. In adults, there is a steady rise in incidence with age, the peak occurring between the ages of 50 and 55.

The brain also is a frequent site of metastasis for other tumors, most commonly cancers of the breast, lung and kidney and malignant melanoma. A previous diagnosis of a cancer elsewhere would make the physician suspect a metastasis rather than a primary brain tumor.

The brain can also be involved by the direct extension of nasal tumors.

Types Of Brain Tumors

Brain tumors arise from various types of cells in the brain, with tumors of supporting tissues being more common than nerve cell tumors. These tumors tend to be named after the kind of cell they arise in.

A tumor of the astrocyte, a neuron-support cell, is referred to as an astrocytoma.

A tumor of the cells lining the open areas inside the spinal cord and brain is an ependymoma.

A tumor of the neurons can be a ganglioneuroma, neuroblastoma or retinoblastoma.

There are more rare tumors of specialized cells within the brain, such as germinoma, pinealoma and choroid plexus carcinoma.

Causes and Risk Factors

Most primary brain tumors have no discernable cause.

Symptoms

There are two broad categories of symptoms. The first results from the increase in pressure in the brain as the tumor expands. The skull is hard and cannot yield, resulting in symptoms such as:

Diagnosis

In addition to a medical history and physical examination, your physician may recommend certain radiologic tests, including a head CT (computed tomography) scan or a head MRI (magnetic resonance imaging).

Treatment

Treatment depends on the type and site of the tumor and the condition of the patient. Surgery is the principal treatment for most primary brain tumors.

With advances in imaging, earlier diagnosis, drugs to decrease brain swelling, sophisticated planning, preoperative and anesthetic management, special microscopes and surgical instruments, it is possible to remove significant amounts of tumor with relative safety.

Modern surgical instruments ensure maximum tumor removal with minimal disruption of normal brain tissue. This includes the ultrasonic aspirator, which disrupts the tumor by ultrasound and then removes it by suction. Specialized laser instruments also have become useful.

Surgery has a number of roles, including attempts at curative resection (removal of tissue), gross total resection, incomplete or subtotal resection, or simple biopsy. There are also procedures to relieve pressure, such as placing shunts within the fluid cavities of the brain.

Some tumors, especially those that are histologically benign, can be cured by complete removal. These may include neurofibromas, meningiomas, acoustic schwannomas and low-grade astrocytomas.

Sometimes, a tumor will be appear to be controlled, but will recur. Another operation may be done in an attempt to improve control.

Gamma knife surgery (stereotactic radiosurgery) is revolutionizing the treatment of some problems in the brain, including benign tumors in treacherous locations, like the brain stem or near the optic nerve. The patient wears a helmet for the procedure. The helmet has many small round holes in it that aim the radiation so that narrow beams of gamma rays are all aimed at a single tiny target. The treated tissue thus receives a strong dose of radiation with minimal to no damage to surrounding tissue. The painless procedure, usually performed under local anesthesia with mild sedation, takes 15 to 40 minutes, depending on the size of the area of treatment. If necessary, the beams can be refocused and the procedure repeated until the entire diseased area is treated. If there are multiple tumors or if the tumor spreads to another area, radiosurgery may be repeated.

More traditional forms of radiation therapy may also be considered complimentary treatment for brain tumors (or a primary method)if surgery cannot completely remove the tumor.

In some cases, chemotherapy (medications) may be given in combination with radiation therapy.

Questions to Ask Your Doctor

Are tests needed for diagnosis or to determine origin?

What type of tumor is it?

Where is its origin?

How serious is the condition?

What treatment will you recommend? What are the side effects?

How successful is this treatment?

Will surgery be necessary? What are the risks? What can be expected after surgery?

Will any medication be prescribed? What are the side effects?

What is the prognosis?