Colorectal cancer screening
USMLE Step 2 CKDifficulty: easyLast updated:
A 45-year-old woman comes for a routine health maintenance visit. She has no gastrointestinal symptoms. She has no personal history of colorectal polyps, inflammatory bowel disease, or abdominal radiation, and no family history of colorectal cancer or hereditary cancer syndromes. Her physical examination and complete blood count are normal. She asks about colorectal cancer screening.
Which of the following is the most appropriate recommendation?
Answer and explanation
Correct answer: D. Begin screening now, for example with colonoscopy every 10 years or an annual fecal immunochemical test
The USPSTF (2021) recommends screening for colorectal cancer in all adults aged 50 to 75 years (grade A) and in adults aged 45 to 49 years (grade B). This expanded the starting age from 50 to 45. This 45-year-old woman has no personal or family risk factors and no symptoms, so she is at average risk and should begin screening now. Recommended strategies include high-sensitivity guaiac FOBT or FIT every year, stool DNA-FIT every 1 to 3 years, CT colonography every 5 years, flexible sigmoidoscopy every 5 years (or every 10 years plus annual FIT), and colonoscopy every 10 years. Serum CEA is not a screening test. Colonoscopy every 3 years is more frequent than recommended for average-risk people with a normal examination.
Each option explained
- A. Screen only if she develops rectal bleeding or a change in bowel habitsIncorrect. Screening is intended for asymptomatic people; symptoms warrant diagnostic evaluation, not screening.
- B. Measure serum carcinoembryonic antigen annuallyIncorrect. CEA is used for surveillance after colorectal cancer treatment, not for screening.
- C. Perform colonoscopy every 3 years starting nowIncorrect. The recommended colonoscopy screening interval for average-risk adults is every 10 years.
- D. Begin screening now, for example with colonoscopy every 10 years or an annual fecal immunochemical testCorrect. The USPSTF recommends screening average-risk adults starting at age 45, using any recommended strategy at its interval.
- E. Delay screening until age 50 because she is at average riskIncorrect. Age 50 was the previous starting age; screening is now recommended for adults aged 45 to 49 (grade B).
Key point
The USPSTF recommends colorectal cancer screening for average-risk adults aged 45 to 75 (45–49: grade B; 50–75: grade A).
From the source
“The USPSTF recommends screening for colorectal cancer in adults aged 45 to 49 years.”