Management of dysplasia in IBD: Discussion
Health system implications[edit source]
Clinical practice[edit source]
Dedicated inflammatory bowel disease (IBD) services able to provide high-quality colonoscopy and advanced endoscopic imaging technologies are recommended. Expert referral centres that can perform endoscopic mucosal resection, endoscopic submucosal dissection and full-thickness resections are required to reduce the need for colectomy. Dedicated training of advanced imaging techniques used in IBD surveillance is recommended. Confirmation of dysplasia with a second experienced gastrointestinal pathologist is required to confirm diagnosis and establish the grade of dysplasia.
Endoscopic resection of dysplasia, followed by close surveillance, can reduce the need for colectomy. Treatment should be individualised according to a patient's wishes. Recommendations should be provided following a multidisciplinary discussion incorporating colorectal surgeon, gastroenterologist and pathologist.
Surveillance for IBD-associated dysplasia should be performed in dedicated tertiary centres by endoscopists with expertise in IBD surveillance. These centres should have access to high quality, high-definition white-light endoscopy and chromoendoscopy. Inflammatory bowel disease patients with a high risk of dysplasia, including those with concurrent primary sclerosing cholangitis or prior flat dysplasia might benefit from panoramic imaging such as full-spectrum endoscopy combined with chromoendoscopy. This would ensure a standardised, high level of care and constitute a platform for education and training, as well as permit data-collection and creation of a centralised database of IBD-associated dysplasia.
Since the initial 2011 version of these guidelines, there has been an overall move away from routine colectomy in patients with high-grade dysplasia (HGD). Although the overall incidence of HGD is low, the expertise available for high-quality IBD surveillance utilising chromoendoscopy and high-definition colonoscopy may only be available at a restricted number of centres. Since these patients may require intensive surveillance, this might generate a greater IBD surveillance workload at such expert centres and a greater need for IBD patients, particularly those from rural and remote areas, to travel to expert centres. Notwithstanding this, these guidelines are not anticipated to alter current resourcing levels as the overall incidence of HGD is low (approximately 3.2% of all IBD patients).
Resources will need to be allocated towards:
- recruitment and training of additional medical, nursing and support personnel to operate dedicated surveillance endoscopy lists, supported by expert gastrointestinal pathologists experienced in dysplasia diagnosis, and colorectal surgical units experienced in IBD surgery.
- purchase and installation of high-resolution endoscopes, dye-spray catheters and pump sets for chromoendoscopy, and endoscopy systems that can provide panoramic imaging to reduce miss rates of dysplasia. Inflammatory bowel disease centres should be resourced to conduct advanced endoscopic resection.
Barriers to implementation[edit source]
Barriers to implementation of the recommendations for colonoscopic surveillance and management of dysplasia in patients with IBD include:
- poor awareness of surveillance guidelines
- low-quality surveillance colonoscopy
- too frequent surveillance colonoscopies or inappropriate performance of surveillance procedures in patients with a low yield of dysplasia (e.g. proctitis or ileitis), in whom surveillance is not indicated
- shortage of resources
- lack of awareness of dysplasia surveillance guidelines
- lack of established IBD centres to provide dysplasia surveillance.
Attitudes of gastroenterologists will determine willingness to refer patients to a specialized IBD endoscopy unit for a service they themselves could provide.
Unresolved issues[edit source]
Elevated dysplasia in IBD[edit source]
Nomenclature for IBD-related dysplasia needs to be standardised to allow physicians to communicate colonoscopic and histopathologic findings effectively. The ongoing use of descriptions such as dysplasia associated lesion or mass (DALM) and ALM is impractical and does not guide management of dysplasia in IBD. Use of these terms should be discouraged.
Long term data are needed to assess the impact of endoscopic resection followed by close surveillance on the natural history of IBD patients, in whom dysplasia develops.
High-grade dysplasia in IBD[edit source]
The natural history of HGD remains unclear. Studies that have evaluated HGD are limited by low patient numbers or the small size of the cohort with HGD within a much larger group including patients with LGD. More longitudinal studies are needed to develop a better understanding of HGD.
More studies are needed to understand patient preferences and decision-making in the setting of dysplasia, given that the natural history of HGD is likely to remain elusive for the foreseeable future. While it is generally perceived that patients prefer colonoscopic surveillance over colectomy, it is also well known that clinicians are poor patient surrogates. In the absence of robust data about the likelihood of developing colorectal cancer (CRC), patient preference data are needed to assist with shared decision making.
The appropriate frequency of surveillance after complete resection of HGD is unclear. More frequent surveillance colonoscopies following resection of HGD would seem to be a sensible extrapolation of existing post-polypectomy surveillance recommendations in non-IBD patients. While this would seem reasonable, more studies are needed define appropriate surveillance intervals.
Surgical resection for HGD or CRC in Crohn's disease is typically a total proctocolectomy, as segmental resections might be followed by the development of Crohn's disease at the anastomosis. However, these recommendations are based upon small series and, in patients with limited and well-controlled Crohn's colitis, the risk of metachronous or synchronous CRC might be low.
Low-grade dysplasia in IBD[edit source]
The recommendations for surveillance colonoscopy in preference to colectomy in the setting of LGD are largely individualised. To date there are no studies which compare surveillance colonoscopy with colectomy for managing LGD, or which clarify the natural history of visible dysplastic lesions managed by endoscopic resection.
Indefinite dysplasia in IBD[edit source]
Histologic indefinite dysplasia (ID) may be due to ongoing low-grade inflammation, and it is important to take ongoing disease activity into account when evaluating a diagnosis of ID. Repeat examination after treating inflammation can be helpful in this case. The natural history of ID is unknown, and the risk for progression to cancer appears to be low. Studies on ID do not routinely report the presence of associated inflammation and, in the past, have not used current methods of classifying flat/polypoid dysplasia.
Studies currently underway[edit source]
No large prospective trials on ID are underway. Some larger units periodically report on ulcerative colitis surveillance outcomes collected prospectively, and these data may add insight regarding long-term outcomes of ID.
Future research priorities[edit source]
Longitudinal cohort studies reporting long-term outcomes of patients opting for endoscopic resection or colonoscopic surveillance are required.
Longitudinal cohort studies of outcomes from surveillance versus colectomy are necessary. The formation of a centralised database could assist in this endeavour.
Clarification of the long-term outcomes for indefinite dysplasia is required. Prospective evidence as to whether repeat examination with enhanced imaging techniques improves lesion detection or outcomes (or otherwise) is needed.
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- Toh JWT. Surgery for Colorectal Cancer in Crohn's Disease: Should We Perform a Total Proctocolectomy for All Patients With High-Grade Dysplasia and Cancer in Crohn's Disease? Dis Colon Rectum 2017 Aug;60(8):e605 Available from: http://www.ncbi.nlm.nih.gov/pubmed/28682975.