Introduction Bone metastases, also called "bone mets," are deposits of cancers within the bone, which occurs when a cancer spreads from somewhere else in the body. This is different than a primary bone tumor, which starts in the bone. Bone metastases develop in many people with cancer at some point in the course of their disease. Some cancers that are more likely to spread to the bone include breast, prostate, and lung cancer. Let's use an example to better understand this latter concept: a lung cancer is first formed in the lung tissue, but tumor cells can break off from the original mass and travel through the bloodstream or lymph system to other areas of the body, including the bone. This spreading of the tumor is known as "metastasis". When a lung cancer metastasizes to the bone, this "bone cancer" is actually lung cancer cells. It sounds odd, but if the ... read more on Bone Metastases: The Basics