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Preventive health care, 2001 update: colorectal cancer screening


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Preventive health care, 2001 update: colorectal cancer screening

Recommendation grade [A, B, C, D, E] and level of evidence [I, II-1, II-2, II-3, III] are indicated after each recommendation. These definitions are repeated following the recommendations. Citations in support of individual recommendations are identified in the guideline text.

Average Risk Individuals

Screening with the Hemoccult test: There is good evidence to include screening with Hemoccult test in the periodic health examination of asymptomatic patients over age 50 with no other risk factors [A,I]. However, there remain concerns about the high rate of false-positive results, feasibility and small clinical benefit of such screening (over 1000 individuals must be screened for 10 years to avert one death from colorectal cancer). For patients being screened with Hemoccult, it is recommended that they avoid red meat, cantaloupe and melons, raw turnips, radishes, broccoli and cauliflower, vitamin C supplements and aspirin and non-steroidal anti-inflammatory drugs for 3 days before fecal samples are collected. However, a recent meta-analysis of 4 randomized controlled trials found no improvement in positivity rates or change in compliance rates with moderate dietary restrictions.

Screening with sigmoidoscopy: There is evidence from case control studies, to recommend that flexible sigmoidoscopy be included in the periodic health examination of patients over age 50 [B, II-2, III]. There is insufficient evidence to make recommendations about whether only 1 or both of fecal occult blood testing and sigmoidoscopy should be performed [C, I].

Screening with colonoscopy: There is insufficient evidence to include or exclude colonoscopy as an initial screen in the periodic health examination [C, II-3]. Although colonoscopy is the best method for detecting adenomas and carcinomas, it may not be feasible to screen asymptomatic patients because of patient compliance and the expertise and equipment required and the potential costs. On the other hand, if colonoscopy were an effective screening strategy when performed at less frequent intervals, these issues might be of less concern.

Above Average Risk Individuals

Individuals at Risk for Familial Adenomatous Polyposis (FAP): The Task Force recommends genetic testing of individuals at risk for familial adenomatous polyposis if the genetic mutation has been identified in the family and if genetic testing is available [B, II-3]. If the individual carries the mutation, then he or she should be screened with flexible sigmoidoscopy beginning at puberty [B, II-3]. Individuals from families where the gene mutation has been identified but are negative themselves, require screening similar to the average risk population. For at risk individuals where the mutation has not been identified in the family or where genetic testing is not available, screening with annual or biannual flexible sigmoidoscopy should be undertaken beginning at puberty. In all instances, genetic counseling should be performed prior to genetic testing.

Individuals at Risk for Hereditary Non-Polyposis Colon Cancer (HNPCC): Patients in kindreds with the cancer family syndrome (HNPCC) have a high risk of colorectal cancer and a high incidence of right-sided colon cancer. Thus, colonoscopy rather than sigmoidoscopy is recommended for screening such patients. Based on Level III evidence, the Task Force recommends screening with colonoscopy in individuals from hereditary non-polyposis colon cancer kindreds [B, II-3]. Although higher levels of evidence are usually required to give a B recommendation, the Task Force realizes that it is unlikely that more rigorous studies could be performed in this cohort of patients given the high risk of cancer and relative infrequency of hereditary non-polyposis colon cancer. The ages when screening should begin and the frequency at which colonoscopy should be performed are unclear.

Individuals with a Family History of Polyps or Colon Cancer: Patients who have only one or two first-degree relatives with colorectal cancer should be screened in the same way as average risk individuals. There is insufficient evidence to recommend colonoscopy for individuals who have a family history of colorectal polyps or cancer but do not fit the criteria for hereditary non-polyposis colon cancer [C, III]. While there is evidence that there is an increased prevalence of neoplasms in these individuals, there is insufficient information to recommend more intense screening than that of individuals at average risk. Further delineation of the risk for individuals with multiple affected family members and family members with early age of diagnosis of colorectal cancer is necessary.

Because most screening options are multiphasic, it is preferable that there is adequate infrastructure to support the implementation, assure quality control and the timely follow-up of screened individuals.

Recommendation Grade

Good evidence to support the recommendation that the condition or maneuver be specifically considered in a periodic health examination (PHE).
Fair evidence to support the recommendation that the condition or maneuver be specifically considered in a periodic health examination.
Insufficient evidence regarding inclusion or exclusion of the condition or maneuver in a periodic health examination, but recommendations may be made on other grounds.
Fair evidence to support the recommendation that the condition or maneuver be specifically excluded from a periodic health examination.
Good evidence to support the recommendation that the condition or maneuver be specifically excluded from a periodic health examination.
Quality of evidence was rated according to 5 levels

I - Evidence from at least 1 properly randomized controlled trial (RCT).

II-1 - Evidence from well-designed controlled trials without randomization.

II-2 - Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group.

II-3 - Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here.

III - Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees.

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