Colorectal Cancer Screening Works Over Long-Term

The results of a study published in the New England Journal of Medicine, suggest that it pays to follow colorectal cancer screening recommendations—and people who do follow the guidelines are less likely to develop colon cancer than people who do not.

Colorectal cancer remains the second leading cause of cancer-related death in the United States. Colorectal cancer often begins with the development of an adenomatous polyp. These polyps often take 10 to 15 years to transform into cancer. Because this development phase is so long, screening and early detection can play a role in the prevention of colorectal cancer, as detection and removal of the polyps can prevent the development of the disease.

For people at average risk of colorectal cancer, the American Cancer Society recommends that routine screening begin at age 50. There are many screening tests available, but colonoscopy remains the gold standard. During a colonoscopy, a physician examines the full length of the large intestine and removes polyps.

Researchers followed 88,902 subjects over 22 years and found that people who underwent endoscopic screenings were less likely to develop colon cancer than those who didn’t. Subjects who had clean colonoscopies were 56 percent less likely to develop the disease compared with their counterparts who were not screened. Similarly, those who had clean sigmoidoscopies were 40 percent less likely and those who had clean polypectomies were 43 percent less likely to develop the disease unscreened subjects.

What’s more—the researchers estimated that 40 percent of the colon cancers that developed during the study period would have been prevented if all participants had undergone colonoscopies.

The researchers concluded that colonoscopy and sigmoidoscopy were associated with a reduced incidence of the distal colorectum. Colonoscopy was also associated with a modest reduction in the incidence of proximal colon cancer. Screening colonoscopy and sigmoidoscopy were associated with reduced colorectal-cancer mortality; however, only colonoscopy was associated with reduced mortality from proximal colon cancer.

Reference:

Nishihara R, Wu K, Lochhead P, et al. Long-Term Colorectal-Cancer Incidence and Mortality after Lower Endoscopy. New England Journal of Medicine. 2013; 369:1095-1105.

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