What is metastatic brain cancer?

Cancer cells that develop in a body organ such as the lung (primary cancer tissue type) can spread via direct extention, or through the lymphatic system and/or through the bloodstream to other body organs such as the brain. Tumors formed by such cancer cells that spread (metastasize) to other organs are called metastatic tumors. Metastatic brain cancer is a mass of cells (tumor) that originated in another body organ and has spread into the brain tissue. Metastatic tumors in the brain are more common than primary brain tumors. They are usually named after the tissue or organ where the cancer first developed (for example, metastatic lung orbreast cancer tumors in the brain, which are the most common types found). Occasionally, an abbreviated name may be used that often confuses people; for example, "small cell brain cancer" actually means "small cell lung cancer that has metastasized to the brain." People should not hesitate to ask their doctor about any terms they do not understand.