What is a brain metastasis?
A brain metastasis is a tumor that travels to the brain from another area of the body. If cancer is metastatic, it means that cancer cells from a tumor have spread to another area of the body through the blood stream, lymphatic drainage system, or by direct extension. The original source of the cancer, or primary cancer, determines the type of cancer, but the location where the new tumor develops is called the metastatic site or location. Brain metastases commonly migrate to the brain through the bloodstream, and tend to be found in areas where the size of the arteries narrow and cause the flow of blood to be slowed. Brain metastasis is usually indicative of an advanced state of cancer. Lung cancer and breast cancer are the most common types of primary cancer that lead to brain metastases. Gastrointestinal (stomach and intestine) cancer and genitourinary (genital and urinary) cancer, as well as skin cancer are also commonly found to be the source of brain metastases. Once metastases ar
