Metastatic Brain Tumor For more information, please visit our Comprehensive Brain & Spinal Tumor site What are Metastatic Brain Tumors? In adults, metastatic brain tumors are the most common type of brain tumors. These are tumors that begin to grow in another part of the body, then spread to the brain through the bloodstream. When the tumors spread to the brain, they commonly go to the part of the brain called the cerebral hemispheres, or to the cerebellum. Often, a patient may have multiple metastatic tumors in several different areas of the brain. Lung, breast, and colon cancers frequently travel to the brain, as do certain skin cancers. Metastatic brain tumors may be quite aggressive and may return even after surgery, radiation therapy, and chemotherapy.