NIH Press Release
National Cancer Institute

Tuesday, Mar. 25, 1997

NCI Press Office
(301) 496-6641

Cancers of the Colon and Rectum

Cancers of the colon and rectum are some of the most common cancers in both men and women in the United States, with more than 131,000 new cases expected to be diagnosed in 1997. These cancers kill nearly 55,000 Americans each year, making them the second leading cause of cancer death.

Between 1973 and 1992, the annual rate of new colorectal cancer cases for all races dropped by 1 percent, and the death rate fell by 17 percent. The trend continued into the 1990s, with deaths falling 5.4 percent between 1991 and 1995.


Understanding Risk. Studies have shown that lifestyle factors may cause colon and rectum cancers. A diet high in fruits and vegetables and fiber and low in fat appears to reduce the risk of getting colorectal cancer. Exercise may also lower a person's risk for the disease.

Prevention. Increased use of flexible sigmoidoscopy and colonoscopy, procedures that use lighted tools that doctors insert into the rectum to look at the inside of the intestine, has made it simpler for doctors to remove abnormal growths before they turn into cancer.

Early Detection. Routine use of annual fecal occult blood tests has proven useful in identifying people who should have further tests to rule out colon cancer and other diseases.

New Drugs. Doctors have found new drugs that work with fluorouracil (5-FU) to treat colorectal cancer better than 5-FU alone. Until the mid-1970s, 5-FU was the mainstay of drug treatment for colorectal cancer patients.

Drugs With Surgery. After surgery, drug treatment has been found to improve the cure rate of certain patients at high risk by about one-third.

Quality of Life. New surgical techniques have reduced to a small fraction the number of colorectal cancer patients needing permanent colostomy bags.

Genetics. The discovery of four genes involved in hereditary nonpolyposis colon cancer (HNPCC) has provided crucial clues to the role of DNA repair in the development of colon and other cancers. Scientists have also identified genes involved in the more common, noninherited form of colon cancer.


Diet. Scientists continue to pursue leads on how certain foods may cause colorectal cancer and how other foods may prevent it.

Early Detection. The National Cancer Institute's Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial may show whether screening tests can reduce deaths from cancers of the colon and rectum.

Genetics. Scientists are studying genes to find better ways of diagnosing and treating colon cancer. For example, a new gene test could eventually allow doctors to detect tumors by looking at stool samples rather than tissue removed through surgery.

Vaccines and Antibodies. Scientists are working on new vaccines and monoclonal antibodies that may improve the way patients' immune systems respond to cancers of the colon and rectum.

Computer Technologies. Researchers are working to develop "virtual colonoscopy," in which doctors use three-dimensional computer graphics to view the entire colon in less than two minutes without the need for inserting a sigmoidoscope or colonoscope.

Additional Reading

Cohen A.M., Minsky B.D., Schilsky R.L. "Colon Cancer," Cancer: Principles and Practice of Oncology; 4th ed., edited by Vincent T. DeVita, Jr., Samuel Hellman, and Steven A. Rosenberg. Philadelphia: J.B. Lippincott, 1993, pp. 929-977.

Greenwald P. "Colon Cancer Overview," Cancer (Supplement), 1992; 70(5), pp. 1206S-1215S.

Statistics are from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database (January 1997) and from the American Cancer Society's Cancer Facts and Figures - 1997, which contains estimates based on SEER data.

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