Brain Metastases

Definition

Brain Metastases is a cancer that has spread to the brain from another site in the body, commonly the lung or breast.

Description

Other primary tumors that metastasize to the brain include melanoma, sarcomas, and tumors arising in the kidney or colon. In addition, unknown primaries sometimes present with brain metastases. The incidence of brain metastasis is far more prevalent than primary brain cancer.

When a cancer spreads (metastasizes) from its original site to another area of the body, it is termed metastatic cancer. Virtually all cancers have the potential to develop this way. Whether metastases do develop depends on the complex interaction of many tumor cell factors, most of which are not completely understood.

Metastases spread in three ways - by local extension from the tumor to the surrounding tissues; through the bloodstream to distant sites; or through the lymphatic system to neighboring or distant lymph nodes. Each kind of cancer may have a typical route of spread.

Symptoms

Many patients have no or minimal symptoms related to the tumor, and their metastases are found during a routine medical evaluation. If there are symptoms, they depend on the site involved. Brain metastases may cause headaches, dizziness, blurred vision, nausea or other symptoms related to the nervous system.

Diagnosis

Studies may include head MRI (magnetic resonance imaging) and head CT (computed tomography) scanning.

Treatment

The treatment of brain metastases depends on factors such as the tumor of origin, the number and location of lesions within the brain and the extent of cancer in places other than the brain.

Radiotherapy is the primary treatment for brain metastases. Cranial irradiation provides palliation to the large majority of patients. Higher doses may be considered for patients whose systemic metastases are controlled.

Steroids are usually administered with radiotherapy in patients with symptoms due to brain metastases; steroids are sometimes administered with radiotherapy in asymptomatic patients.

Surgical treatment of brain metastases is limited to a few situations, such as diagnosis in patients with obvious primary tumor. Emergency craniotomy to relieve increased intracranial pressure is sometimes life-saving. In most cases, however, treatment with high-dose corticosteroids (dexamethasone in particular) may eliminate the need for such surgery.

In the rare patient with presentation of a resectable tumor and single brain metastasis, surgical resection of the solitary brain lesion is indicated with appropriate postoperative chemotherapy and/or irradiation of the primary tumor site, and postoperative whole-brain irradiation.

Chemotherapy has a limited role in treating brain metastases. Many chemotherapy drugs do not cross the blood-brain barrier but can reach malignant tumors in the brain, presumably through a local breakdown in the blood-brain barrier. In some chemotherapy-sensitive tumors like lymphoma, testicular carcinoma, small cell lung cancer, and breast carcinoma, chemotherapy can produce complete radiographic remissions, but its eventual place as a solitary therapy is still under evaluation.

Questions to Ask Your Doctor

Do any tests need to be done to determine what kind of cancer is involved and/or its origin?

What treatment do you recommend?

How soon will you start treatment and how long will it last?

What are the side effects of them treatments?

What is the success rate of the treatment?

Will you be prescribing any medications? What are the side effects?

Will surgery be considered? If so, what can be expected from surgery?

What is the prognosis?