The term chemotherapy, or chemo., refers to a wide range of drugs used to treat cancer. These drugs usually work by killing dividing cells. Since cancer cells have lost many of the regulatory functions present in normal cells, they will continue to attempt to divide when other cells do not. This trait makes cancer cells susceptible to a wide range of cellular poisons.

The chemotherapy agents work to cause cell death in a variety of ways. Some of the drugs are naturally occurring compounds that have been identified in various plants and some are man-made chemicals. A few different types of chemotherapy drugs are briefly described below. For more information on a particular type of drug, choose from the list below.

• Antimetabolites: Drugs that interfere with the formation of key bio-molecules within the cell including nucleotides, the building blocks of DNA. These drugs ultimately interfere with DNA replication and therefore cell division.

• Genotoxic Drugs: Drugs that damage DNA. By causing DNA damage, these agents interfere with DNA replication, and cell division.(1)

• Spindle Inhibitors: These agents prevent proper cell division by interfering with the cytoskeletal components that enable one cell to divide into two.(1)

• Other Chemotherapy Agents: These agents inhibit cell division by mechanisms that are not covered in the three categories listed above.

Normal cells are more resistant to the drugs because they often stop dividing when conditions are not favorable. Not all normal dividing cells escape however, a fact that contributes to the toxicity of these drugs. Cell types that are normally rapidly dividing, such as those in the bone marrow and in the lining of the intestine, tend to be hardest hit. Death of the normal cells produces some of the common side-effects of chemotherapy.