How Cancer Cells Spread in the Body

Cancer can sometimes be found in several parts of the body. Most of the time, these are not separate types of cancer. Rather, cancer has developed in one organ and spread to other areas. When cancer spreads, it’s called metastasis.

In metastasis, cancer cells break away from where they first formed, travel through the blood or lymph system, and form new tumors in other parts of the body. Cancer can spread to almost anywhere in the body. But it commonly moves into your bones, liver, or lungs.

When these new tumors form, they are made of the same kind of cancer cells as the original tumor. For example, lung cancer cells that are found in the brain don’t look like brain cells. This disease would be called metastatic lung cancer, not brain cancer.

Cancer cells can be sent to the lab for tests to identify the origin of the cells. Knowing the type of cancer and whether it has spread helps the health care team suggest a treatment plan. The goal of treatment is to stop or slow the growth of cancer or to relieve symptoms.

A new animated video, Metastasis: How Cancer Spreads, shows how cancer cells can break off from the primary tumor in one organ, travel through a blood vessel, and invade another organ to form a new tumor. Watch the video and learn more about how cancer spreads at www.cancer.gov/types/metastatic-cancer.