Putting Prevention into Practice
An Evidence-Based Approach
Routine Aspirin or Nonsteroidal Anti-inflammatory Drugs for the Primary Prevention of Colorectal Cancer
Am Fam Physician. 2009 Feb 15;79(4):325-326.
B.L., a 37-year-old Asian man, comes to your office for a physical examination. He mentions that he started taking a daily aspirin because he heard that it would reduce his risk of heart attack and colorectal cancer. You review B.L.’s medical history and determine that he is not at increased risk of coronary heart attack. He has no personal history of gastrointestinal problems, but his 64-year-old uncle was recently diagnosed with colon cancer. You advise B.L. that only patients at increased risk should use aspirin to prevent cardiovascular events and that taking aspirin is not recommended to prevent colorectal cancer.
Case Study Questions
Based on information from the U.S. Preventive Services Task Force (USPSTF), which one of the following statements explains why B.L. should not take aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) to prevent colorectal cancer?
A. Aspirin use is associated with an increase in the incidence of colorectal cancer.
B. Aspirin or NSAID use does not decrease the incidence of adenomatous polyps.
C. The harms of aspirin or NSAID use to prevent colorectal cancer outweigh the benefits.
D. Colorectal cancer screening is a more appropriate preventive strategy for persons of B.L.’s age.
E. Asians have a higher risk of colorectal cancer than other races.
Taking a daily aspirin increases the incidence of which of the following adverse events?
A. Gastrointestinal bleeding.
B. Hemorrhagic stroke.
C. Cardiovascular events.
D. Renal impairment.
The USPSTF recommends against the routine use of aspirin or NSAIDs to prevent colorectal cancer in adults at average risk of colorectal cancer. A patient with which one of the following factors would be considered at average risk of colorectal cancer?
A. A personal history of colorectal cancer.
B. Familial adenomatous polyposis.
C. Hereditary nonpolyposis colon cancer syndromes.
D. A family history of colorectal cancer.
E. A personal history of colorectal adenomas.
1. The correct answer is C. The harms of aspirin or NSAID use to prevent colorectal cancer outweigh the benefits. For this reason, the USPSTF recommends against the routine use of aspirin or NSAIDs to prevent colorectal cancer in persons at average risk. Physicians should continue to discuss aspirin chemoprophylaxis with patients who are at increased risk of coronary heart disease.
There is evidence that aspirin (taken in higher doses than recommended for prevention of cardiovascular disease) and NSAIDs may be associated with a reduced incidence of colorectal cancer. Aspirin used over longer periods may also be associated with a reduced incidence of colorectal cancer. Aspirin taken in higher doses, and aspirin or NSAIDs taken for longer periods reduce the incidence of adenomatous polyps.
In 2008, the USPSTF recommended screening for colorectal cancer for all persons beginning at 50 years of age (the age after which more than 80 percent of colorectal cancers occur) and continuing until 75 years of age. This recommendation includes persons with first-degree relatives who have had colorectal adenomas or cancer. Blacks have higher colorectal cancer incidence and mortality rates than Asians. However, the USPSTF recommendations for colorectal cancer screening apply to all ethnic and racial groups.
2. The correct answers are A and B. Taking a daily aspirin increases the incidence of gastrointestinal bleeding and hemorrhagic stroke. NSAID use increases the incidence of gastrointestinal bleeding and renalimpairment, especially in older patients. Cyclooxygenase-2 inhibitors, a class of NSAIDs, increase the incidence of renal impairment and appear to be associated with increased risk of cardiovascular events. Overall, at least moderate harms are associated with aspirin and NSAID use.
3. The correct answer is D. The USPSTF recommendation against the routine use of aspirin or NSAIDs to prevent colorectalcancer classifies adults with a family history of colorectal cancer among those at average risk. Persons with familial adenomatous polyposis, hereditary nonpolyposiscolon cancer syndromes, or a history of colorectal adenomas are at increased risk of colorectal cancer and are not included in the recommendation.
U.S. Preventive Services Task Force. Routine aspirin or nonsteroidal anti-inflammatory drugs for the primary prevention of colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2007;146(5):361–364.
Dubé C, Rostom A, Lewin G, et al. The use of aspirin for primary prevention of colorectal cancer: a systematic review prepared for the U.S. Preventive Services Task Force. Ann Intern Med. 2007;146(5):365–375.
Rostom A, Dubé C, Lewin G, et al., for the University of Ottawa Evidence-based Practice Center. Use of aspirin and NSAIDs to prevent colorectal cancer. Rockville, Md.: Agency for Healthcare Research and Quality; 2007.
The case study and answers to the following questions on routine aspirin or nonsteroidal anti-inflammatory drugs for the primary prevention of colorectal cancer are based on the recommendations of the U.S. Preventive Services Task Force (USPSTF), an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services. More detailed information on this subject is available in the USPSTF Recommendation Statement and the evidence synthesis on the USPSTF Web site (http://www.ahrq.gov/clinic/uspstfix.htm). The evidence synthesis and Recommendation Statement are available in print through the AHRQ Publications Clearinghouse (800-358-9295, e-mail,firstname.lastname@example.org). The practice recommendations in this activity are available at http://www.ahrq.gov/clinic/uspstf/uspsasco.htm.
Copyright © 2009 by the American Academy of Family Physicians.
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