A 54-year-old man presents for a periodic health examination. His family history is significant
for his mother who died of a cerebrovascular accident at age 72, his father who died of a
myocardial infarction at age 68, and a brother who developed sigmoid cancer at age 60. The
patient is on no medications except for aspirin, 81 mg daily. His physical examination is
unremarkable. The patient asks for a recommendation regarding current cancer screening. Which
of the following is the most appropriate screening test for this patient?
A. Annual digital rectal examination and fecal occult blood testing
B. Flexible sigmoidoscopy
C. Flexible sigmoidoscopy and barium enema
D. Colonoscopy
E. Genetic testing for the p53 gene
Explanation:
The correct answer is D. Any patient with a first-degree relative who has developed an adenoma
or colorectal cancer should undergo colonoscopy for screening at age 50, or 10 years before the
relative developed the adenoma or carcinoma, whichever comes first. This patient has a brother
who has a colon cancer at age 60; therefore, a full colonoscopy is warranted. Although there are
various opinions regarding appropriate screening in the “average risk individual,” there is a
consensus that full colonoscopy is required in patients who have an increased risk, e.g., firstdegree
relative with a positive history.
Annual digital rectal examination and fecal occult blood testing (choice A) are no longer
considered a reliable method of screening for colon cancer, since a shift in the demographics of colon cancer has lead to more than half being identified in the first half of the colon. Digital
rectal examination also often fails to identify premalignant colonic polyps.
Flexible sigmoidoscopy (choice B) is a good initial screening technique for patients older than 50
with no specific known risk factors. If polyps are identified, they can be biopsied, their type
established, and subsequent complete colonoscopy performed if adenomas were identified
microscopically.
Flexible sigmoidoscopy and barium enema (choice C) offers an alternative way of screening the
entire colon in patients in whom a complete colonoscopy cannot be performed.
Genetic testing for the p53 gene (choice E) is not currently used for colon cancer screening.