Normal, healthy cells divide and grow in a well-established pattern. When these cells divide, an identical copy is produced. The body only makes the number of normal cells it needs at any given time. As each normal cell matures, it loses its ability to reproduce. Normal cells are also preprogrammed to die at specific times. In contrast, tumor cells reproduce uncontrollably and grow in unpredictable ways. They invade surrounding tissue and disrupt normal body functions.

All chemotherapy drugs work in some way to interfere with the cancer cells’ ability to live, divide, and multiply. Here are some of the types of drugs used to treat solid tumors:

•  Alkaloids. These drugs are derived from plants and interrupt cell division through a variety of mechanisms, including interfering with DNA and specific enzyme activities. They also disrupt the membrane (outer wall) of the cancer cell, causing cell damage or cell death.

•  Alkylating agents. All cells contain DNA and RNA, which contain the instructions cells need to make exact copies of themselves. Alkylating agents poison cancer cells by interacting with DNA or RNA to prevent cell reproduction.

•  Antibiotics. This type of drug prevents cell growth by blocking reproduction, weakening the outer wall of the cell, or interfering with certain cell enzymes.

•  Antimetabolites. These drugs starve cancer cells by replacing essential cell nutrients when cells are preparing to divide.

•  Immunotherapeutic agents. These substances, usually used in targeted therapies, either encourage the cancerous cells to die or help the body destroy them. One category of immunotherapy drugs being used to treat cancer are anti-angiogenesis agents. These drugs disrupt the blood supply to the tumor, depriving it of nutrients it needs to grow.