What is brain metastasis?
Brain metastasis is the spread of a primary tumor to the brain. Metastasis is different from primary brain tumor. People often confuse these two types of tumors. For example, a lung cancer initially forms in the lung tissue, but the tumor cells can break away from the main mass and travel to other parts of the body, including the brain, through the bloodstream or lymphatic system. This tumor spread is known as “metastasis”. When a lung cancer metastasizes to the brain, it is a “brain tumor” that is actually a lung cancer cell.
Which metastases are more common?
Among tumors, lung cancer accounts for the largest number of brain metastases, with 25% of patients experiencing brain metastasis at some point in their disease. Other cancers that commonly metastasize to the brain include melanoma, breast cancer, colon cancer, and kidney cancer. Although these cancers are more common in the brain, other types of cancers can spread to the brain.
Signs, symptoms and diagnosis
Common symptoms of brain metastasis include changes in cognitive abilities (memory, attention, reasoning), behavioral changes, ataxia (instability), visual changes, aphasia (difficulty finding words), headaches, weakness, and seizures.
Are tumors and cancers that metastasize to the brain treatable?
Yes, depending on the type of lesion, the size of the mass, the number of masses and their initial origin, radiotherapy or chemotherapy can be used.
The risk of brain metastases is due to the space they occupy in the brain and the pressure they exert on the surrounding tissue. This pressure can cause symptoms such as headaches, speech problems, seizures, nausea / vomiting, weakness or vision problems. The goal of initial treatment is to reduce some of this pressure on brain tissue by reducing swelling using corticosteroids (dexamethasone, prednisone). Medications can be taken orally or by intravenous injection. Some patients may experience relief symptoms soon after starting a steroid. However, this does not mean that the tumor is completely gone. If the patient is diagnosed with metastasis, he or she may receive anticonvulsant medication to prevent further seizures.
Treatment decisions for each patient are made based on the type of tumor, general health, age, presence / control of cancer outside the brain, and number of brain metastases.
For patients with a single brain lesion, surgery may be a good option, especially if the tumor is under control in the rest of the body. However, the lesion should be in an area of the brain where surgery is safe. A study of patients with solitary cerebral metastases who underwent surgical treatment with brain radiation therapy (WBRT) had a higher quality of life than patients who underwent WBRT alone. Life was also higher in these patients.
Whole brain radiotherapy
Whole brain radiotherapy (WBRT) is radiation to the whole brain. This radiation is usually between 10 and 15 doses and is often used in patients with poor prognostic factors, patients who are not candidates for surgery or patients with more than 3 brain lesions. Many patients receive WBRT with other treatments (surgery, radiotherapy). The goal of whole brain cleansing is to kill all the cancer cells in the brain that may still exist but are not large enough to form a mass that can be detected by radiology. Therefore, the cure for the whole brain is to kill all the cancer cells.
Stereotactic Radiotherapy (SRS)
Radiotherapy is not surgery but the very precise irradiation of a high dose of radiation to the part of the brain where the tumor is located. Unlike conventional external beam radiation, which is usually given daily for several weeks, SRS is spread in one dose (Gamma Knife®) or up to five doses (Cyberknife®). More than one brain tumor can be treated in one treatment session (for example, if a patient has two separate brain metastases, both can be treated on the same day.