Colon neoplasia more common in UC-PSC than Crohn's-PSC

NEW YORK - Patients with primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) may have a more severe disease course and a greater risk of colon neoplasia and colectomy, than patients with PSC and Crohn's disease (CD), new findings suggest.

However, an inflammatory bowel disease (IBD) specialist who did not participate in the research says the findings should not change current clinical practice, in which patients with either IBD type who are diagnosed with PSC undergo annual colonoscopy for colorectal cancer surveillance.

"It's a good start, but we need more work to understand how we can intervene and how we might even modify the outcomes," Dr. David Rubin, chief of the section of gastroenterology, hepatology and nutrition at University of Chicago Medicine, told Reuters Health.

PSC, or scarring within the bile ducts, is more common among people with IBD, especially UC. Colon neoplasia risk is higher among UC patients with PSC than it is for UC patients without PSC, but the relationship among PSC, CD and colorectal cancer is not as well understood.

To investigate, Dr. Udayakumar Navaneethan of The Cleveland Clinic and colleagues looked at 273 patients with PSC and IBD, including 223 patients with UC and 50 with CD. Median follow-up was 12 years for the PSC-UC patients and 14 years for the PSC-CD patients.

Their findings were published in Gastroenterology Reports, online October 29.

The PSC-UC patients averaged one flare a year, versus zero for the PSC-CD patients (p<0.001). Colon neoplasia developed in 35.9% of the PSC-UC group, compared to 18% of the PSC-CD group (p=0.009). Proportional hazards analysis showed a 12% higher risk of colectomy and a 56% higher risk of colon neoplasia for the UC patients, although neither difference reached statistical significance.

"Although the difference is not significant, it may be clinically relevant and our study was probably underpowered to detect a difference; however, it was also interesting to note that CD in PSC patients presents with colonic disease with occasional small bowel involvement and, in most cases, mimics UC," Dr. Navaneethan and his team write. "The other limitation is that PSC patients in our cohort had a high risk of colectomy and colon neoplasia compared with previous reports, probably because of tertiary referral bias."

Dr. Rubin said he was "disappointed" that the authors did not discuss the potential clinical implications of their findings in the paper, or possible explanations for why colon neoplasia risk would be higher in PSC-UC than PSC-CD.

He emphasized that physicians caring for IBD patients should be aware that they are at increased risk of colorectal cancer, and that for IBD patients diagnosed with PSC, that risk is higher. Also, he added, patients without known IBD who are diagnosed with PSC should immediately undergo a colonoscopy to determine if they do in fact have UC or CD.

"Chronic inflammation in any organ is associated with a downstream risk of cancer," Dr. Rubin said. "It behooves us to have a prevention strategy."


Gastroenterol Rep 2014.

References: Reuters Health
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