Cancer Chemoprevention Holds Promise
American Cancer Society
Statistics that show one in two men and one in three women will get cancer in their lifetimes might lead some to think cancer is nearly inevitable. But a new review points out carcinogenesis is a long, multistep process that requires a particular combination of events, any one of which, if interrupted, may prevent or delay the development of cancer. Appearing in the May/June issue of the American Cancer Society's peer-reviewed journal, CA: A Cancer Journal for Clinicians, the review focuses on cancer chemoprevention: using chemical agents to stop any one or several of those steps along the way in hopes of preventing or delaying an abnormal cell from ever becoming cancer.
Investigators from the University of Texas MD Anderson Cancer Center highlight current clinical research into chemoprevention and propose new research directions based on insights gained through better understanding of the mechanisms of tumor formation.
The review calls the FDA's approval of tamoxifen for prevention of breast cancer a landmark achievement in chemoprevention that crowned 20 years of research into chemoprevention. The drug has been shown to prevent breast cancer in women at increased risk and to reduce recurrences among breast cancer survivors. But the drug is not without risks. The authors review several promising new, less toxic agents.
Despite promising epidemiological data, say the authors, most dietary changes have not been successful in preventing colorectal cancer, the third leading cause of cancer death in both men and women. And while aspirin and COX-2 inhibitors have shown promise in colon cancer prevention, more studies are needed before they could replace screening as effective ways to prevent the disease.
The review also details promising data and limitations in the practice of chemoprevention for cancers of the head and neck, lung, bladder, prostate, skin, and cervix. The authors conclude the continued success of chemoprevention will depend on several factors, including devising tumor-specific risk models to identify patients who would most benefit, more research using gene targeting and knockout models, and locating new targets for therapy.
Tsao A, Kim E, Hong W "Chemoprevention of Cancer," CA Cancer J Clin 2004;54:150-180.
For more information, or to contact American Cancer Society, see their website at: www.cancer.org
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