Practice Guidelines
Colorectal Cancer Screening: ACP Guidance Statements
Am Fam Physician. 2020 Aug 15;102(4):250-252.
Author disclosure: No relevant financial affiliations.
Key Points for Practice
• Screening reduces CRC mortality in patients 50 to 75 years of age, with greatest benefit in patients older than 60 years.
• The ACP recommends screening average-risk patients with one of the following: colonoscopy every 10 years, flexible sigmoidoscopy every 10 years with biennial FIT, biennial guaiac FOBT, or biennial FIT.
• Because of limited evidence of benefit and increased harms, neither FIT with stool DNA testing nor CT colonography is a recommended screening method.
From the AFP Editors
Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. Up to 80% of CRC develops from colonic adenomas over five to 20 years, illustrating the potential benefit of early detection. Only 10% of adenomas progress to CRC over 10 years; the rest stabilize or regress. The American College of Physicians (ACP) developed a consensus statement for CRC screening of average-risk adults based on their review of six independent guidelines and supporting evidence. People at elevated risk are subject to other screening recommendations and are not addressed here.
Overall Recommendations
The ACP recommends routine screening of average-risk adults between 50 and 75 years of age to reduce CRC mortality. Screening is not recommended after 75 years of age or when life expectancy is less than 10 years. Several screening methods are recommended (Table 1), with decisions based on patient preferences.
ACP Recommended Colorectal Cancer Screening Methods for Average-Risk Adults
| Screening method | Recommended screening interval | Number needed to screen to prevent one death from colorectal cancer | Patient benefits | Important harms |
|---|---|---|---|---|
Recommended | ||||
Colonoscopy | Every 10 years | Unknown | Definitive study | Requires colon preparation and anesthesia Risk of colon perforation (NNH = 384 to 2,500) Risk of major bleeding (NNH = 294 to 1,250) |
Flexible sigmoidoscopy and FIT | Flexible sigmoidoscopy every 10 years and FIT every two years | 850 over 11 years (flexible sigmoidoscopy alone); 2,000 for < 60 years; 345 for ≥ 60 years | Proven mortality benefit | Requires colon preparation Often requires anesthesia Risk of major bleeding (NNH = 5,000) Will miss proximal disease; recommended with biennial FIT |
FIT | Every two years | Unknown | No colon preparation Single stool sample No dietary restrictions False-negative test results are less than one in 1,000 | One false positive in every 11 tests requires unnecessary colonoscopy |
Guaiac fecal occult blood testing | Every two years | 377 over 18 years | Proven mortality benefit No colon preparation | Dietary restrictions Multiple stool samples One in 182 tests will be a false negative, missing cancer One in 82 tests will be a false positive that requires unnecessary colonoscopy |
Not recommended | ||||
FIT with stool DNA | Every three years | Unknown | No colon preparation Single stool sample No dietary restrictions Predicts fewer false-negative test results than FIT | Specificity lower than FIT, increasing false positives that require unnecessary colonoscopy Positive stool DNA result may lead to overly aggressive testing |
Computed tomography colonography | Every five years | Unknown | Accuracy similar to colonoscopy | Requires colon preparation Radiation exposure Positive test results require colonoscopy Incidental extracolonic findings in up to 69% of tests |
Note: The NNHs were calculated by the author based on data provided in the original ACP guideline.
ACP = American College of Physicians; FIT = fecal immunochemical testing; NNH = number needed to harm.
ACP Recommended Colorectal Cancer Screening Methods for Average-Risk Adults
| Screening method | Recommended screening interval | Number needed to screen to prevent one death from colorectal cancer | Patient benefits | Important harms |
|---|---|---|---|---|
Recommended | ||||
Colonoscopy | Every 10 years | Unknown | Definitive study | Requires colon preparation and anesthesia Risk of colon perforation (NNH = 384 to 2,500) Risk of major bleeding (NNH = 294 to 1,250) |
Flexible sigmoidoscopy and FIT | Flexible sigmoidoscopy every 10 years and FIT every two years | 850 over 11 years (flexible sigmoidoscopy alone); 2,000 for < 60 years; 345 for ≥ 60 years | Proven mortality benefit | Requires colon preparation Often requires anesthesia Risk of major bleeding (NNH = 5,000) Will miss proximal disease; recommended with biennial FIT |
FIT | Every two years | Unknown | No colon preparation Single stool sample No dietary restrictions False-negative test results are less than one in 1,000 | One false positive in every 11 tests requires unnecessary colonoscopy |
Guaiac fecal occult blood testing | Every two years | 377 over 18 years | Proven mortality benefit No colon preparation | Dietary restrictions Multiple stool samples One in 182 tests will be a false negative, missing cancer One in 82 tests will be a false positive that requires unnecessary colonoscopy |
Not recommended | ||||
FIT with stool DNA | Every three years | Unknown | No colon preparation Single stool sample No dietary restrictions Predicts fewer |
Coverage of guidelines from other organizations does not imply endorsement by AFP or the AAFP.
This series is coordinated by Michael J. Arnold, MD, contributing editor.
A collection of Practice Guidelines published in AFP is available at https://www.aafp.org/afp/practguide.
Copyright © 2020 by the American Academy of Family Physicians.
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