A 36-year-old man presents to his physician for routine follow-up. He was diagnosed with ulcerative colitis 5 years ago and is currently treated with mesalamine. His symptoms are well controlled, and he reports 1–2 formed bowel movements daily without blood. Over the past several months, he has developed intermittent fatigue and pruritus. Physical examination is notable for mild scleral icterus.
Laboratory studies demonstrate the following:
Magnetic resonance cholangiopancreatography (MRCP) demonstrates multifocal stricturing and dilation of the intrahepatic and extrahepatic bile ducts. A diagnosis of primary sclerosing cholangitis is made.
Which of the following is the most appropriate recommendation regarding colorectal cancer surveillance?
The correct answer is:
A) Colonoscopy every 1–2 years beginning now
This patient has ulcerative colitis complicated by primary sclerosing cholangitis (PSC). One high-yield association on Step 2 is that PSC substantially increases the risk of colorectal cancer in patients with inflammatory bowel disease. As a result, these patients require more intensive surveillance than patients with ulcerative colitis alone.
PSC is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the intrahepatic and extrahepatic bile ducts. The diagnosis is suggested by pruritus, cholestatic liver enzyme elevation, and the characteristic “beading” appearance on MRCP due to alternating strictures and dilations. Approximately 70%–80% of patients with PSC have underlying inflammatory bowel disease, most commonly ulcerative colitis.
Patients with both PSC and ulcerative colitis are considered a particularly high-risk group for colorectal cancer. Current recommendations are to begin surveillance colonoscopy at the time PSC is diagnosed and continue at frequent intervals, generally every 1–2 years, regardless of the duration or activity of colitis. This recommendation is more aggressive than standard ulcerative colitis surveillance because cancer risk is substantially elevated.
A common Step 2 challenge is distinguishing the surveillance recommendations for:
The presence of PSC places this patient into the highest-risk category.
Answer choice B: Colonoscopy every 10 years beginning at age 45, is incorrect.
This recommendation applies to average-risk colorectal cancer screening. Patients with ulcerative colitis and PSC have a markedly increased colorectal cancer risk and require much more frequent surveillance.
Answer choice C: Colonoscopy only if gastrointestinal symptoms worsen, is incorrect.
Colorectal cancer surveillance is based on cancer risk, not symptom severity. Many patients develop dysplasia or early cancer while their ulcerative colitis remains clinically quiescent.
Answer choice D: Fecal immunochemical testing annually, is incorrect.
FIT testing is not an adequate surveillance strategy for patients with inflammatory bowel disease. Colonoscopy is required to evaluate for dysplasia and early malignancy.
Answer choice E: No additional colorectal cancer surveillance is required, is incorrect.
PSC significantly increases colorectal cancer risk in patients with ulcerative colitis. Failure to perform surveillance would expose the patient to a substantial risk of delayed cancer diagnosis.
Key Learning Point
Primary sclerosing cholangitis is strongly associated with ulcerative colitis and significantly increases the risk of colorectal cancer. Patients with both conditions should undergo surveillance colonoscopy beginning at the time PSC is diagnosed and continuing every 1–2 years.
