What is Metastatic Brain Tumor?

When cancer originates in another body part and spreads to the brain, it is called a Metastatic Brain Tumor. When cancer originates within the brain itself, it is called a primary brain tumor. In this booklet, we will limit our education to Metastatic Brain Tumors.

Solitary Metastatic Brain Tumor: When only one brain tumor is seen on the scans of a patient with a known cancer diagnosis elsewhere in the body, such as the lungs, breasts or another organ.

Brain Metastases: Two or more tumors in the brain originating from another part of the body.

Patients with cancer are at risk for metastasis to the brain. The most common metastatic brain tumors occur in patients with lung cancer, breast cancer, melanoma and renal cancer. In the last decade, medical oncologists have made remarkable strides in cancer treatment. With the addition of immunotherapy and more targeted treatment methods, cancer patients are living much longer.

Blood Brain Barrier (BBB): The human brain is protected by a very selective barrier made of tightly packed cells. This barrier allows important nutrients to enter the brain while keeping certain toxins out. Unfortunately, this mechanism works against most chemotherapy and some immunotherapy agents used to treat cancer. In other words, agents that help treat cancer in the other body parts may not help with a tumor that has metastasized (spread) to the brain.

A great deal of research and progress has been made in the last few years, and new drugs with better BBB penetration will likely be available in the future.