Although the word chemotherapy can mean the use of any drug (such as aspirin or penicillin) to treat any disease, to most people chemotherapy refers to drugs used for cancer treatment. Two other medical terms often used to describe cancer chemotherapy are antineoplastic (meaning anti-cancer) therapy and cytotoxic (cell-killing) therapy.

History of chemotherapy

The first drug used for cancer chemotherapy did not start out as a medicine. Mustard gas was used as a chemical warfare agent during World War I and was studied further during World War II. During a military operation in World War II, a group of people were accidentally exposed to mustard gas and were later found to have very low white blood cell counts. Doctors reasoned that an agent that damaged the rapidly growing white blood cells might have a similar effect on cancer. Therefore, in the 1940s, several patients with advanced lymphomas (cancers of certain white blood cells) were given the drug by vein, rather than by breathing the irritating gas. Their improvement, although temporary, was remarkable. That experience led researchers to look for other substances that might have similar effects against cancer. As a result, many other drugs have been developed.

Why chemotherapy is different from other treatments

Chemotherapy is the first choice for treating many cancers. It differs from surgery or radiation in that it is almost always used as a systemic treatment. This means the drugs travel throughout the body to reach cancer cells wherever they may have spread. Treatments like radiation and surgery act only in a specific area such as the breast, lung, or colon, and so are considered local treatments.

More than 100 drugs are used today for chemotherapy -- either alone or in combination with other drugs or treatments. As research continues, more drugs are expected to become available. These drugs vary widely in their chemical composition, how they are taken, their usefulness in treating specific forms of cancer, and their side effects. New drugs are first developed through research in test tubes and animals. Then the drugs are tested in clinical trials in humans to find out how safe they are and how well they work.

Chemotherapy in clinical trials

Clinical trials are studies of new or experimental drugs or other new treatment methods. These studies are done when there is a reason to believe a new drug or a new combination of drugs may be of value in curing or controlling cancer.

If you wish to take part in a clinical trial, the researchers will fully explain the requirements to you and your family. You can always refuse to take part in the study, or leave the study at any time if you change your mind. Being in a clinical trial does not keep you from getting other medical or nursing care that you need.

People who take part in clinical trials make an important contribution to medical care because the study results will also help future patients. At the same time, they may be among the first to benefit from these new treatments. For more information, please see the American Cancer Society document, Clinical Trials: What You Need to Know.

The American Cancer Society offers a clinical trials matching service for patients, their families, and friends. You can reach this service by calling 1-800-303-5691, or through our Web site at www.cancer.org. Based on the information you provide about your cancer type, stage, and previous treatments, the service will compile a list of clinical trials that match your medical needs. In finding a center most convenient for you, the service can also take into account where you live and whether you are willing to travel.

You can also get a list of current clinical trials by calling the National Cancer Institute's (NCI) Cancer Information Service toll free at 1-800-4-CANCER or visiting the NCI clinical trials Web site at www.cancer.gov/clinicaltrials.

Go back to Chemotherapy Principles

Last Medical Review: 06/17/2009
Last Revised: 06/17/2009