What is the process called when cells move from a primary tumour to form secondary tumours?

Metastasis is the process by which cancer cells break away from a primary tumor, travel through the bloodstream or lymphatic system, and establish new tumors, known as secondary tumors, in other parts of the body. This process is a critical characteristic of cancer progression and significantly impacts treatment decisions and prognoses.

Metastasis involves several steps, including local invasion of surrounding tissues, entry into the circulatory system, survival in circulation, and eventual colonization of distant organs. It is essential for understanding how cancer can spread and why it can be more challenging to treat once metastasis has occurred.

Both metaplasia and apoptosis are unrelated processes. Metaplasia refers to the reversible transformation of one type of cell into another type, often in response to stress or injury, but it does not relate to the movement of cancer cells. Apoptosis is the programmed cell death that occurs in normal and diseased tissues, but it does not describe how cancer cells migrate to form new tumors. Angiogenesis is the formation of new blood vessels, which supports tumor growth but is also not directly the process of tumor spread.