What term is used to describe the spread of cancer to distant sites?

The term that describes the spread of cancer to distant sites is metastasis. This process involves cancer cells breaking away from the original (primary) tumor, traveling through the bloodstream or lymphatic system, and forming new tumors (secondary tumors) in other parts of the body. Metastasis is a critical factor in cancer progression and significantly impacts treatment decisions, prognosis, and overall management of the disease.

In contrast, invasion refers to the direct extension and infiltration of cancer cells into surrounding tissues, which is often the first step in the process before metastasis occurs. Relapse typically refers to the return of cancer after a period of improvement, while recurrence indicates the reappearance of cancer at the same site after it has been treated. These terms relate to different aspects of cancer dynamics, whereas metastasis specifically focuses on the dissemination of cancer to distant organs or tissues.