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ABSTRACT: Colorectal cancer is a significant contributor to morbidity and mortality in the United States. Studies published in the early 1990s, showing that screening for colorectal cancer can reduce colorectal cancer-related mortality, led many organizations to recommend screening in asymptomatic, average-risk adults older than 50 years. Since then, however, national screening rates remain low. Several important studies published over the past four years have refined our understanding of existing screening tools and explored novel means of screening and prevention. The most important new developments, which are reviewed in this article, include the following: Additional trial results support the effectiveness of fecal occult blood testing in reducing the incidence of, and mortality from, colorectal cancer. New studies document the sensitivity of fecal occult blood testing, sigmoidoscopy, and double-contrast barium enema compared with colonoscopy. Cost-effectiveness models show that screening by any of several methods is cost-effective compared to no screening. Randomized trials show that calcium is effective but fiber is not effective in preventing reoccurrence of adenomatous polyps. Preliminary data suggest that nonsteroidal anti-inflammatory drugs may prevent adenomatous polyps and that DNA stool tests and virtual colonoscopy may show promise as screening tools. This new information provides further support for efforts to increase the use of colorectal cancer screening and prevention services in adults older than 50 years.
ABSTRACT: This article describes a joint update of guidelines by the American Cancer Society and the U.S. Multi-Society Task Force on Colorectal Cancer delineating evidence-based surveillance recommendations for patients after polypectomy and colorectal cancer resection. Although there are some qualifying conditions, the following general guidelines apply: after colonoscopic polypectomy, patients with hyperplastic polyps should be considered to have normal colonoscopies, and subsequent colonoscopy is recommended at 10 years. Patients with one or two small (less than 1 cm) tubular adenomas, including those with only low-grade dysplasia, should have their next colonoscopy in five to 10 years. Patients with three to 10 adenomas, any adenoma 1 cm or larger, or any adenoma with villous features or high-grade dysplasia should have their next colonoscopy in three years. Following curative resection of colorectal cancer, patients should undergo a colonoscopy at one year, with subsequent follow-up intervals determined by the results of this examination. Adoption of these guidelines will have a dramatic impact on the quality of care provided to patients after a colorectal cancer diagnosis, will assist in shifting available resources from intensive surveillance to screening, and will ultimately decrease suffering and death related to colorectal cancer.
Update on Colorectal Cancer - Article
ABSTRACT: An estimated 129,400 new cases of colorectal cancer occurred in the United States during 1999. The lifetime risk of developing this cancer is 2.5 to 5 percent in the general population but two to three times higher in persons who have a first-degree relative with colon cancer or an adenomatous polyp. Between 70 and 90 percent of colorectal cancers arise from adenomatous polyps, whereas only 10 to 30 percent arise from sessile adenomas. Tumors or polyps that develop proximal to the splenic flexure carry a poorer prognosis than those that arise more distally, in part because of delayed diagnosis secondary to later development of symptoms. The Dukes system is the classic staging method for colorectal cancer; the TNM staging system is more detailed and therefore more useful for surgical purposes. Although screening guidelines vary, most agree that colorectal cancer screening should begin at 50 years of age in patients without a personal or family history of colorectal cancer.
When Is the Right Time to Repeat Colonoscopy? - Editorials
Routine Aspirin or Nonsteroidal Anti-inflammatory Drugs for the Primary Prevention of Colorectal Cancer: Recommendation Statement - U.S. Preventive Services Task Force
Flexible Sigmoidoscopy - Article