Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. Cytotoxic means toxic to cells. Cytotoxic chemotherapy drugs disrupt the way cancer cells grow and divide but they also affect normal cells. Sometimes chemotherapy is used alone to treat some types of cancer. But often it is used with other treatments such as surgery, radiotherapy, hormonal therapy, or other anti-cancer drugs such as targeted therapies.
Chemotherapy is commonly given at regular intervals called cycles. A cycle may be a dose of one or more drugs followed by several days or weeks without treatment. This gives normal cells time to recover from drug side effects. Sometimes, doses may be given a certain number of days in a row, or every other day for several days, followed by a period of rest. Some drugs work best when given continuously over a set number of days.
