Colonoscopy Surveillance and Management of Dysplasia in Inflammatory Bowel Disease

ESD and Pit Pattern Diagnosis: Lessons from a Japanese Endoscopist Working in the United States

Endoscopic submucosal dissection (ESD) was developed in 2000s to overcome the limitations of endoscopic mucosal resection (EMR), especially to accomplish en-bloc resection, and it has been accepted worldwide in the past decades. Many ESD devices and diagnosis modalities are currently available, which include pit pattern and narrow band imaging (NBI) diagnoses to evaluate the depth of the tumor preoperatively with sensitivities of 70 to 90%. Depending on the Japanese colorectal guideline, the intramucosal cancer and shallow invasion of the submucosal layer are the main good indications of ESD; however, the ESD practices between Japan and Western countries still vary, including pathologic definition of cancer, tumor/node/metastasis classification, and handling of ESD specimen. In the United States, despite the large demand for treatment of colorectal neoplasm, pit pattern and magnified NBI diagnoses are not widely accepted yet, and piecemeal EMR is still the major method in most of the institutions. Moreover, the specific guideline of ESD is also not available yet. More new technologies are being developed other than conventional ESD methods in Eastern and Western countries, and ESD is now expected to change in the next generation. It is recommended that not only gastroenterologists but also colorectal surgeons have appropriate knowledge of colorectal lesions and their management to ensure current treatments is applied to patients.

Endoscopic detection and resection of dysplasia in inflammatory bowel disease-techniques with videos

BACKGROUND

Patients with ulcerative colitis and Crohn's colitis have an increased risk of developing dysplasia and colorectal cancer as compared to the general population; surveillance colonoscopy is recommended in this patient population.

METHODS

This review of the published literature aimed to assess the published evidence.

RESULTS

Detection of dysplasia requires examination of mucosa with targeted biopsies of the visible lesions as well as random biopsies to detect invisible lesions. Newer endoscopic techniques, in particular chromoendoscopy, increase the yield of identifying dysplastic lesions. The surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients International Consensus (SCENIC) guidelines recommends that colonoscopy using chromoendoscopy is the optimal endoscopic surveillance strategy to detect dysplasia. Once dysplastic lesions are discovered on surveillance endoscopic examination, careful and meticulous descriptions of lesions is mandatory to aid in further decision making. Management of dysplastic lesions in inflammatory bowel disease patients depends on endoscopic (morphological) and histologic findings and patient characteristics such as age, general condition of the patient, and patient preferences. Endoscopic mucosal resection, endoscopic submucosal dissection, and surgery are different therapeutic options for colonic dysplastic lesions detected in the setting of inflammatory bowel disease.

CONCLUSIONS

In this review, we discuss the various techniques for endoscopic resection of dysplasia in patients with inflammatory bowel disease. Further research is required to determine the optimal approach to diagnosis and management of dysplasia in patients with inflammatory bowel disease.

Quantitative or qualitative transcriptional diagnostic signatures? A case study for colorectal cancer

Background

Due to experimental batch effects, the application of a quantitative transcriptional signature for disease diagnoses commonly requires inter-sample data normalization, which would be hardly applicable under common clinical settings. Many cancers might have qualitative differences with the non-cancer states in the gene expression pattern. Therefore, it is reasonable to explore the power of qualitative diagnostic signatures which are robust against experimental batch effects and other random factors.

Results

Firstly, using data of technical replicate samples from the MicroArray Quality Control (MAQC) project, we demonstrated that the low-throughput PCR-based technologies also exist large measurement variations for gene expression even when the samples were measured in the same test site. Then, we demonstrated the critical limitation of low stability for classifiers based on quantitative transcriptional signatures in applications to individual samples through a case study using a support vector machine and a naïve Bayesian classifier to discriminate colorectal cancer tissues from normal tissues. To address this problem, we identified a signature consisting of three gene pairs for discriminating colorectal cancer tissues from non-cancer (normal and inflammatory bowel disease) tissues based on within-sample relative expression orderings (REOs) of these gene pairs. The signature was well verified using 22 independent datasets measured by different microarray and RNA_seq platforms, obviating the need of inter-sample data normalization.

Conclusions

Subtle quantitative information of gene expression measurements tends to be unstable under current technical conditions, which will introduce uncertainty to clinical applications of the quantitative transcriptional diagnostic signatures. For diagnosis of disease states with qualitative transcriptional characteristics, the qualitative REO-based signatures could be robustly applied to individual samples measured by different platforms.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4446-y) contains supplementary material, which is available to authorized users.

Surveillance of patients with inflammatory bowel disease

Patients with inflammatory bowel disease involving the colon are at increased risk for developing colorectal cancer. Colonoscopy surveillance is important to identify and treat IBD associated dysplasia. The SCENIC consensus provides evidence-based recommendations for optimal surveillance and management of dysplasia in IBD. Chromoendoscopy, with the surface application of dyes to enhance mucosal visualization, is the superior endoscopic surveillance strategy to detect dysplasia. Most dysplasia is visible, and can be endoscopically resected. Future studies should determine the effect of new surveillance strategies on the incidence of CRC and mortality in patients with IBD.