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Level I – Colorectal Cancer Screening

Level I Services: Preventive services for which clinicians and health systems must assess the need. These services must be recommended to each patient, as they have the highest value and are worthy of attention at every opportunity.

The USPSTF recommendations are fully endorsed by the ICSI Preventive Services work group.
Grade of Recommendation and Level of Certainty as Evaluated by USPSTF
  1. “Screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy or colonoscopy in adults beginning at age 50 years and continuing until age 75 years. The risks and benefits of these screening methods vary.”
  2. “Against routine screening for colorectal cancer in adults ages 76 to 85 years. There may be considerations that support colorectal cancer screening in an individual patient.”
  3. “Against screening for colorectal cancer in adults older than age 85 years.”
  4. “The evidence is insufficient to assess the benefits and harms of computed tomographic colonography and fecal DNA testing as screening modalities for colorectal cancer.”
(USPSTF Last Revised 2008 – Update in Progress)
Grade of Recommendation:
  1. A
  2. C
  3. D
  4. I Statement

Level of Certainty:

  1. Moderate
  2. Moderate
  3. Moderate
  4. Uncertain
“Benefits:
There is convincing evidence that screening with any of the three recommended tests reduces colorectal cancer mortality in adults ages 50 to 75 years. Follow-up of positive screening test results requires colonoscopy regardless of the screening test used. Because of the harms of colonoscopy described below, the chief benefit of less invasive screening tests is that they may reduce the number of colonoscopies required and their attendant risks.
There is adequate evidence that the benefits of detection and early intervention decline after age 75 years. The lead time between the detection and treatment of colorectal neoplasia and a mortality benefit is substantial, and competing causes of mortality make it progressively less likely that this benefit will be realized with advancing age.
Harms:
The primary established harms of colorectal cancer screening are due to the use of invasive procedures initially or in the evaluation sequence. Harms may arise from the preparation the patient undergoes to have the procedure, the sedation used during the procedure, and the procedure itself.
Colonoscopy
Evidence is adequate to estimate the harms of colonoscopy. In the United States, perforation of the colon occurs in an estimated 3.8 per 10,000 procedures. Serious complications – defined as deaths attributable to colonoscopy or adverse events requiring hospital admission, including perforation, major bleeding, diverticulitis, severe abdominal pain, and cardiovascular events – are significantly more common, occurring in an estimated 25 per 10,000 procedures.
Flexible Sigmoidoscopy
Evidence is adequate that serious complications occur in approximately 3.4 per 10,000 procedures.
Fecal Tests
Evidence about the harms of fecal tests is lacking (inadequate), but the USPSTF assesses them to be no greater than small.
CT Colonography
Computed tomographic colonography images more than the colon. Up to 16% of people having their first CT colonography are found to have extracolonic abnormalities that require further testing. Evidence is inadequate to assess the clinical consequences of identifying these abnormalities, but there is potential for both benefit and harm. Potential harms arise from additional diagnostic testing and procedures for lesions found incidentally, which may have no clinical significance. This additional testing also has the potential to burden the patient and adversely impact the health system.
The risks for perforation associated with screening CT colonography in research settings are estimated to be 0 to 6 per 10,000 CT colonography studies. However, these estimates may be higher than what can be expected in screened populations because the studies included symptomatic populations.
Radiation exposure resulting from CT colonography is reported to be 10 mSv per examination. The harms of radiation at this dose are not certain, but the linear no-threshold model predicts that one additional individual per 1,000 would develop cancer in his or her lifetime at this level of exposure. The lifetime cumulative radiation risk from the use of CT colonography to screen for colorectal cancer should be considered in the context of the growing cumulative radiation exposure from the use of other diagnostic and screening tests that involve radiation exposure. On the other hand, improvements in CT colonography technology and practice are lowering this radiation dose.
Benefits-Harms Assessment:
The USPSTF concludes that, for fecal occult blood testing, flexible sigmoidoscopy and colonoscopy to screen for colorectal cancer, there is high certainty that the net benefit is substantial for adults ages 50 to 75 years. Go to Clinical Considerations for a comparison of the regimens for each of these tests.
The USPSTF concludes that, for adults ages 76 to 85 years, there is moderate certainty that the net benefits of screening are small.
The USPSTF concludes that, for adults older than age 85 years, there is moderate certainty that the benefits of screening do not outweigh the harms.
The USPSTF concludes that there is insufficient evidence to assess the sensitivity and specificity of fecal DNA testing for colorectal neoplasia, and that therefore the balance of benefits and harms cannot be determined for this test.
The USPSTF concludes that, for CT colonography, evidence to assess the harms related to extracolonic findings is insufficient, and the balance of benefits and harms cannot be determined.”
ICSI Work Group Qualifications:
1) If available, FIT is preferred over guaiac-based fecal occult blood testing. The fecal immunochemical testing does not require dietary modification for patients as with the guaiac-based test and does not yield false-negative results in the presence of high-dose vitamin C supplementation. It is more specific for lower gastrointestinal bleeding and is therefore preferred over gFOBT as a screening test (Allison, 2007).
2) CT colonography is a colorectal screening option approved by the American Cancer Society for average-risk individuals (Levin, 2008). It is less invasive and does not require procedural sedation but currently has limited availability, is not covered by most payers, and has trouble identifying flat and depressed polyps as well as polyps of less than 5mm in size. It may be an option for colorectal cancer screening in the following clinical situations: after incomplete screening or diagnostic colonoscopy, for anticoagulated patients who cannot safely discontinue anticoagulation therapy.
3) African Americans or American Indians/Alaska Natives should be screened beginning at age 45 years (Perdue, 2008; Agrawal, 2005).
4) Several patient populations are at increased risk and may benefit from screening/surveillance at an earlier age or more frequent interval.
a) Patients with one first-degree relative with either colorectal cancer or adenomatous polyps diagnosed before age 60 years should be evaluated with colonoscopy every five years beginning at age 40 or 10 years before the age of the youngest case in the immediate family.
b) Patients with two or more first-degree relatives diagnosed at any age with colorectal cancer or adenomatous polyps should be evaluated with colonoscopy every five years beginning at age 40 or 10 years before the age of the youngest case in the immediate family.
c) Patients with inflammatory bowel disease, chronic ulcerative colitis and Crohn’s disease should be evaluated with colonoscopy every one to two years starting eight years after the onset of pancolitis or 12-15 years after the onset of left-sided colitis.
d) Patients with genetic diagnosis of familial adenomatous polyposis (FAP) or suspected FAP without genetic testing evidence should be evaluated with annual flexible sigmoidoscopy beginning at age 10 to 12 years and should receive genetic counseling.
e) Patients with genetic or clinical diagnosis of hereditary non-polyposis colorectal cancer should be evaluated with colonoscopy every one to two years beginning at ages 20 to 25 years or 10 years before the age of the youngest case in the immediate family.
In late 2014, the U.S. Food and Drug Administration has approved Cologuard, a screening test using a stool sample, that detects the presence of red blood cells and DNA mutations that may indicate the presence of certain kinds of abnormal growths that may be colon cancer or precursors to cancer. The Centers for Medicare and Medicaid Services has also found that the of evidence of effectiveness of Cologuard is sufficient to cover this test as option for colorectal cancer screening for asymptomatic, average risk beneficiaries.
Relevant Resources:
http://www.uspreventiveservicestaskforce.org/uspstf/uspscolo.htm
FDA Cologuard Approval Statement
CMS Proposed Coverage Decision