Like cancer itself, anticancer drugs come in many varieties. Each is suited to a particular function, depending on the specific goal of that patient's treatment. Several broad categories can be used to classify anticancer drugs, however. These include traditional chemotherapy, targeted therapy, and immunotherapy, among others. A doctor's choice of exactly how to treat a patient with anticancer drugs will depend on the type of cancer in question, its stage of progression, and the preferences of the patient. Anticancer drugs can be used either by themselves or in combination with other types of therapies, such as radiation therapy.
Chemotherapy is one of the most well-known classes of anticancer drugs. The medications used in chemotherapy have the effect of attacking cells that divide at high rates, such as aggressive cancer cells. Unfortunately, the cells of the bone marrow, hair follicles, and gastrointestinal tract also divide at high rates, and are treated in an equally harsh way by anti-cancer drugs. This leads to less blood cell production, intestinal irritation, and hair loss, which may be the most well-known side effect of chemotherapy.
Another, newer group of anticancer drugs is known as targeted therapy. As its name suggests, it has a more specified approach than chemotherapy. Rather than attacking every cell that divides often, targeted therapy drugs interfere with cancer cell growth by blocking specific types of molecules that cancer cells need in order to be generated or to divide. The goal of targeted therapy is to reduce the harm done to normal cells while still fighting the cancer.
For cancerous tumors to grow beyond a certain point, they must tap into the blood supply of the surrounding tissues by constructing their own blood vessels. If they are unable to do this, the tumor's development slows or stops. The anticancer drugs known as angiogenesis inhibitors keep new blood vessels from being formed. This will ideally affect only the tumor, since an adult's body does not construct new blood vessels except as part of the process of healing from an injury.
One of the more intriguing types of anticancer drugs are those which are collectively known as cancer immunotherapy. This essentially means the use of the body's own immune system to hunt down and destroy harmful cells. These drugs can either train the body's immune system to recognize cancer cells as enemies, or they can be used to recruit the immune system to work with the drugs themselves. In this latter case, the drugs are actually therapeutic antibodies that are given as drugs. Their presence then jump-starts the body's immune response toward tumor cells.