OAK BROOK, Ill.,  Nov. 27 -- A U.S. study shows colorectal cancer deaths among men and women dropped 4.3 percent per year from 2002 to 2005, researchers said.

The study, issued annually since 1998 by the American Cancer Society, the National Cancer Institute, the Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries, said the incidence rate for colorectal cancer -- the rate at which new cancers are diagnosed -- dropped 2.8 percent per year among men and dropped 2.2 percent per year among women from 1998 to 2005.

The study showed for the first time a simultaneous decline in both cancer death rates and incidence rates in men and women. The concurrent declines in colorectal cancer mortality and incidence are likely associated with preventing colorectal cancer through screening and removal of precancerous polyps, improving cancer outcomes by earlier stage diagnosis, reducing exposure to risk factors, and improving cancer treatment, the study said.

"This report demonstrates the importance of colorectal cancer screening beginning at age 50," Dr. John L. Petrini, president of the American Society for Gastrointestinal Endoscopy, said in a statement. "Individuals with other risk factors, including a family history of colon cancer or polyps, and African-Americans, may need screening at an earlier age. This disease is largely preventable and curable when diagnosed in its early stages." (UPI)