Metastasis is the process by which cancer cells spread from the primary tumor to distant sites in the body. This occurs through several steps:
1. Local Invasion: Cancer cells invade surrounding tissues. 2. Intravasation: Cells enter the bloodstream or lymphatic system. 3. Circulation: They travel through the circulatory system. 4. Extravasation: Cells exit the bloodstream and invade new tissues. 5. Colonization: They establish new tumors in distant organs.
Metastasis is a major cause of cancer-related mortality, as it often leads to secondary tumors in vital organs like the liver, lungs, and brain.
