Overview of Chemotherapy for Colon Cancer

A look at chemo for colon cancer

senior man receiving chemotherapy
Caiaimage/Martin Barraud/OJO+/Getty Images

Our bodies are made up of billions of cells that grow, divide, and then die in a predictable manner. Cancer occurs when something goes wrong with this system, causing uncontrolled cell division and growth. Chemotherapy literally means "chemical treatment" and is one way to help the body kill off cancer cells and try to keep them from dividing (making more of themselves).

The reason people tend to lose their hair during chemotherapy is that many chemo drugs don't discriminate: They target all cells that divide rapidly.

Our hair falls out all the time. We just don't usually notice because our hair cells reproduce quickly and make more to replace what we've lost. But when a chemo drug reduces rapid cell division across the board, the "good" cells end up taking one for the team.

Chemotherapy is sometimes recommended for stage 2 colon cancer, and usually recommended for stage 3 and stage 4 colon cancer in combination with biologic therapies that specifically target cancer cells. Please explore the Colon Cancer Drug Index to learn about the variety of drugs available.

For information about other ways to treat colon cancer, please read Colon Cancer Treatment Options

Additional Information About Chemotherapy

Ultimately with chemotherapy, the usefulness of a treatment depends on how many cancer cells these chemotherapeutic drugs kill as compared with how badly these agents affect normal cells. After all, you don't want to take drugs that end up not only killing the cancer but also you, too!

A general indicator of the efficacy of cancer drugs is the therapeutic index. The therapeutic index signifies the separation between the toxicity of the agent or medication and the therapeutic potential of the drug. Drugs with a larger therapeutic index are preferred.

Unfortunately, many current chemotherapeutic agents have a pretty narrow therapeutic index.

However, newer drugs in development--including those used to treat colorectal cancer--have larger therapeutic indices because they better target the tumor cells and leave normal cells alone. 

Classically, anticancer drugs and chemotherapeutic agents are first tested in animal models. If these studies in animals are promising, these drugs are further studied to determine optimal scheduling, administration and formulation. Once researchers have a pretty good idea of how the drugs work, they are given to humans. Only drugs that are safe and effective are approved by the FDA. To be sure, bringing a new drug to market takes years of research and costs lots of money, which is one reason why these drugs can get very expensive. 

Of note, the development of more targeted chemotherapy drugs is different from more conventional chemo drugs and involves molecular analysis to determine whether the drug attacks a specific human target that must be present for the drug to work. Human participants in clinical trials express these molecular targets.

Source: "Detailed Guide: Colon and Rectum Cancer: How Is Colorectal Cancer Treated?" American Cancer Society 22 Feb. 2006. Accessed 21 Jul. 2007 [http://www.cancer.org/docroot/CRI/content/CRI_2_4_4x_How_is_colorectal_cancer_treated_10.asp?sitearea=].

Continue Reading