Chemotherapy is the treatment of cancerous diseases with drugs that interfere with cancer cell growth and reproduction. Normal cells grow and die in a controlled way, but when cancer occurs, the cancer cells keep dividing and forming more cancer cells. Chemotherapy destroys cancer cells by preventing them from growing or multiplying. Cancer chemotherapy may consist of a single drug or a combination of drugs and can be administered through a vein, injected into a body cavity or delivered orally in the form of a pill. Chemotherapy drugs circulate in the blood to parts of the body where cancer may have spread and can kill or eliminate cancer cells at sites great distances from original cancer. As a result, chemotherapy is considered a systemic treatment.
Chemotherapy cannot distinguish between cancer cells and healthy cells. Chemotherapy damages rapidly dividing cells, a hallmark trait of cancer cells. However, in the process, healthy cells that are also rapidly dividing, such as blood cells and the cells lining the mouth and GI tract are also damaged. Treatment-related damage to healthy cells leads to complications of treatment or side effects. These side effects may be severe, reducing a patient’s quality of life, compromising their ability to receive their full, prescribed treatment, and sometimes, limiting their chance for an optimal outcome from treatment.