What is metastatic cancer (what does metastasis mean)?

According to the U.S. National Cancer Institute (NCI), cancer that spreads from where it started to a distant part of the body is called metastatic cancer. NCI explains that the process by which cancer cells spread to other parts of the body is called metastasis. Importantly, NCI states that metastatic cancer keeps the identity of the original (primary) cancer: when observed under a microscope and tested in other ways, metastatic cancer cells have features like those of the primary cancer, not like the cells in the place where the metastatic cancer is found. For this reason, NCI notes that metastatic cancer has the same name as the primary cancer — for example, breast cancer that spreads to the lung is called metastatic breast cancer, not lung cancer. This is general information for education, not personal medical advice; discuss your situation with a qualified clinician.

Last updated: 2026-07-12

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