Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 29-year-old man is evaluated during a routine examination. His medical history is significant for ulcerative colitis involving the entire colon, which was diagnosed 4 years ago. His symptoms responded to therapy with mesalamine and have remained in remission on this medication. His family history is significant for a maternal uncle who died of colon cancer at the age of 50 years.
Physical examination is unremarkable.
Serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase levels are normal.
Which of the following is the most appropriate interval at which to perform colonoscopy with biopsies in this patient?
A: Begin now and repeat annually
B: Begin in 4 years and repeat every 1 to 2 years
C: Begin in 4 years and repeat every 10 years
D: Begin at age 40 years and repeat every 5 years
MKSAP Answer and Critique
The correct answer is B: Begin in 4 years and repeat every 1 to 2 years.
The most appropriate colon cancer surveillance strategy is colonoscopy with biopsies beginning in 4 years and repeated every 1 to 2 years. Patients with inflammatory bowel disease have health risks related to their disease or its treatment. Patients with long-standing colitis are at increased risk for colon cancer and should undergo surveillance colonoscopy with biopsies every 1 to 2 years beginning after 8 to 10 years of disease. This recommendation applies to patients with ulcerative colitis involving more than the rectum and those with Crohn colitis involving at least one third of the colon. This patient should begin a surveillance program in approximately 4 years, when his ulcerative colitis has been present for 8 years. He has a single second-degree relative with colon cancer, but this does not affect the surveillance recommendation. Four-quadrant surveillance biopsies should be obtained every 10 cm beginning in the cecum, resulting in approximately 32 to 36 biopsies. In patients with inflammatory bowel disease and concomitant primary sclerosing cholangitis (PSC), the risk of colon cancer is particularly high, and it is recommended that such patients begin yearly surveillance as soon as the diagnosis of PSC is made. However, this patient has normal liver chemistry studies, which makes PSC unlikely.
For patients with Lynch syndrome (hereditary nonpolyposis colorectal cancer), recommended colorectal cancer screening is colonoscopy every 1 to 2 years beginning at age 20 to 25 years, or 2 to 5 years earlier than the youngest age at diagnosis of colorectal cancer if the affected relative was less than 25 years old.
Patients with ulcerative colitis involving the rectum are not at increased risk for colorectal cancer. In these patients, average-risk colorectal cancer screening with colonoscopy is recommended beginning at age 50 years and should be repeated every 10 years.
The 2012 American College of Physicians Guidance Statement on colorectal cancer screening recommends initiation of screening in high-risk patients (a first-degree relative with colon cancer or advanced adenoma diagnosed at age <60 years, or two first-degree relatives diagnosed at any age) at age 40 years, or 10 years younger than the earliest colon cancer diagnosis in the family, whichever is earlier. Colonoscopy is repeated every 5 years.
- Patients with long-standing colitis associated with inflammatory bowel disease are at increased risk for colon cancer and should undergo surveillance colonoscopy every 1 to 2 years beginning after 8 to 10 years of disease.
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