Certain patients with inflammatory bowel disease (IBD), both ulcerative colitis and Crohn's disease of the colon, have an increased risk of developing colorectal cancer compared to individuals without IBD. A number of factors contribute to the increase in risk, which necessitates an individualized and sensible approach to surveillance in patients, according to a new medical position statement and technical review published by the American Gastroenterological Association in its official journal, Gastroenterology.
"The increased risk of developing colorectal cancer in certain patients with IBD prompted the AGA to look at current diagnosis and management protocols to ensure that our patients are receiving the highest level of treatment," according to Francis A. Farraye, MD, primary author of the manuscript. "The recommendations we developed will help guide gastroenterologists to identify high-risk individuals and develop surveillance plans based on each patient's unique situation."
While IBD is relatively rare in the general population, it remains one of the three high-risk conditions predisposing patients to CRC, along with Lynch syndrome and familial adenomatous polyposis. "Although certain patients with IBD have an increased risk of developing colorectal cancer, there is evidence that the risk of developing cancer has decreased over the past several decades," stated senior author Steven Itzkowitz, MD.
Other findings of the medical position statement on diagnosis and management of CRC in IBD patients include:
- Disease duration, more extensive disease, severity of inflammation, primary sclerosing cholangitis (disease of the bile ducts that leads to liver damage), and a positive family history of sporadic CRC are all associated with an increased risk of developing CRC.
- Dysplasia (abnormal cells) detected on biopsy is currently considered the best marker for CRC risk in IBD.
- Patients with IBD and a non-adenoma-like dysplasia-associated lesion or mass that does not lend itself to being completely removed by colonoscopy should be treated with colectomy (removal of all or a portion of the colon). In contrast, patients with an adenoma-like dysplasia-associated lesion or mass removed endoscopically and without evidence of flat dysplasia elsewhere in the colon, can be managed safely by polypectomy and continued surveillance.
- There is a high certainty that colectomy for flat high-grade dysplasia treats undiagnosed synchronous cancer (which may be present in 42 percent to 67 percent of cases).
- The controversy revolving around the management of low-grade dysplasia was reviewed.
- There is moderate certainty that surveillance colonoscopy results in at least moderate reduction of CRC risk in patients with IBD. Patients with extensive ulcerative colitis or Crohn's disease involving much of the colon are the most likely to benefit.
- The authors endorsed the use of chromoendoscopy in high risk patients to identify dysplasia and cancer.
- While there is some evidence that certain medicines used to treat IBD might help to prevent CRC and dysplasia, this requires further research.
- At present, there are no genetic, molecular or biochemical markers that can be measured in the tissue, blood or stool to reliably predict which patients with IBD are at greater risk for dysplasia or cancer, but this is an area of active investigation.
The conclusions of the technical review and medical position statement were based on the best available evidence, or in the absence of quality evidence, the expert opinions of the authors and medical position panel convened to critique the technical review and structure the medical position statement. The technical review and the medical position statement together represent the guideline.
To develop the guidelines, a set of 10 broad questions were identified by experts in the field to encapsulate the most common management questions faced by clinicians. To review recommendations and grades, view the AGA Medical Position Statement on the Diagnosis and Management of Colorectal Neoplasia in Inflammatory Bowel Disease. The guidelines were developed through interaction among the authors, the AGA Institute, the Clinical Practice and Quality Management Committee and representatives from the AGA Institute Council.
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