Cancer is a group of diseases characterized by uncontrolled growth and the spread of abnormal cells caused by a mutation or defect in the genetic material of a cell. If one cell becomes cancerous then all cells that arise from that abnormal cell will also be cancerous. These abnormal cells destroy the part of the body in which they originate and then sometimes spread to other body parts where they start new growth and cause more destruction.
Chemotherapeutic agents are administered to try to slow or stop halt the growth and spread of cancerous cells. They work by causing damage to the DNA of the cancer cells, stopping the cancer cells from replicating by inhibiting DNA production, or stopping mitosis in the cancer cells which stops cell division. Unfortunately, these agents can also cause damage to healthy cells. Because the agents are particularly effective on cells with a high growth rate, certain areas of the body are more effected by them.
Healthy cells, such as those in the hair follicles, gastric epithelium, and bone marrow may be damaged by the agents and cause the common side-effects of hair loss, nausea, and anemia.