Metastasis (muh-tas-tuh-sus) is one of the major causes of death from cancer. It refers to the development of secondary tumors at different locations in the body from the original cancer. Eventually, these tumors interfere with vital body functions, and if they don't respond to treatment, will prove fatal. Most metastases (muh-tas-tuh-sees) form by cancer cells dividing and spreading through the capillaries and veins. They also spread through the lymphatic (lim-fa-tick) system and through the body's cavities. The most common areas for metastasis to occur are in the bones, lungs, liver, and central nervous system. Once a cancer has spread to other parts of the body, it is much harder to treat successfully. That's why it is so important to have regular check-ups and cancer screenings. Early detection is the best protection. For more information on the spread of cancer, contact a healthcare professional.