Systematic review with meta-analysis: incidence and factors for progression to advanced neoplasia in inflammatory bowel disease patients with indefinite and low-grade dysplasia

Endoscopic approaches to the management of dysplasia in inflammatory bowel disease: A state-of-the-art narrative review

Patients with inflammatory bowel disease (IBD) are at an increased risk of developing colitis-associated neoplasia (CAN), including colorectal cancer (CRC), through the inflammation-dysplasia-neoplasia pathway. Dysplasia is the most reliable, early and actionable marker for CAN in these patients. While such lesions are frequently encountered, adequate management depends on an accurate assessment, complete resection and close surveillance. With recent advances in endoscopic technologies and research in the field of CAN, the management of dysplastic lesions has significantly improved. The American Gastroenterology Association and Surveillance for Colorectal Endoscopic Neoplasia Detection (SCENIC) provide a guideline framework for approaching dysplastic lesions in patients with IBD. However, there are significant gaps in these recommendations and real-world clinical practice. Accurate lesion assessment remains pivotal for adequate management of CAN. Artificial intelligence-guided modalities are now increasingly being used to aid the detection of these lesions further. As the lesion detection technologies are improving, our armamentarium of resection techniques is also expanding and includes hot or cold polypectomy, endoscopic mucosal resection, endoscopic sub-mucosal dissection and full-thickness resection. With the broadened scope of endoscopic resection, the recommendations regarding surveillance after resection has also changed. Certain patient populations such as those with invisible dysplasia or with prior colectomy and ileal pouch anal anastomosis need special consideration. In the present review, we aim to provide a state-of-the-art summary of the current practice of endoscopic detection, resection and surveillance of dysplasia in patients with IBD and provide some perspective on the future directions based on the latest research.

Dynamic Prediction of Advanced Colorectal Neoplasia in Inflammatory Bowel Disease

BACKGROUND & AIMS

Colonoscopic surveillance is recommended in patients with colonic inflammatory bowel disease (IBD) given their increased risk of colorectal cancer (CRC). We aimed to develop and validate a dynamic prediction model for the occurrence of advanced colorectal neoplasia (aCRN, including high-grade dysplasia and CRC) in IBD.

METHODS

We pooled data from 6 existing cohort studies from Canada, The Netherlands, the United Kingdom, and the United States. Patients with IBD and an indication for CRC surveillance were included if they underwent at least 1 follow-up procedure. Exclusion criteria included prior aCRN, prior colectomy, or an unclear indication for surveillance. Predictor variables were selected based on the literature. A dynamic prediction model was developed using a landmarking approach based on Cox proportional hazard modeling. Model performance was assessed with Harrell's concordance-statistic (discrimination) and by calibration curves. Generalizability across surveillance cohorts was evaluated by internal-external cross-validation.

RESULTS

The surveillance cohorts comprised 3731 patients, enrolled and followed-up in the time period from 1973 to 2021, with a median follow-up period of 5.7 years (26,336 patient-years of follow-up evaluation); 146 individuals were diagnosed with aCRN. The model contained 8 predictors, with a cross-validation median concordance statistic of 0.74 and 0.75 for a 5- and 10-year prediction window, respectively. Calibration plots showed good calibration. Internal-external cross-validation results showed medium discrimination and reasonable to good calibration.

CONCLUSIONS

The new prediction model showed good discrimination and calibration, however, generalizability results varied. Future research should focus on formal external validation and relate predicted aCRN risks to surveillance intervals before clinical application.

Natural course of ulcerative colitis in China: Differences from the West?

BACKGROUND AND AIMS

Whether the natural course of ulcerative colitis (UC) in mainland China is similar or different from that in Western countries is unknown, and data on it is limited. We aimed to provide a comprehensive description of the natural course of UC in China and compare it with Western UC patients.

METHODS

Based on a prospective Chinese nationwide registry of consecutive patients with inflammatory bowel diseases, the medical treatments and natural history of UC were described in detail, including disease extension, surgery, and neoplasia. The Cox regression model was used to identify factors associated with poor outcomes.

RESULTS

A total of 1081 UC patients were included with a median follow-up duration of 5.3 years. The overall cumulative exposure was 99.1% to 5-aminosalicylic acids, 52.1% to corticosteroids, 25.6% to immunomodulators, and 15.4% to biologics. Disease extent at diagnosis was proctitis in 26.9%, left-sided colitis in 34.8%, and extensive colitis in 38.3%. Of 667 patients with proctitis and left-sided colitis, 380 (57.0%) experienced disease extent progression. A total of 58 (5.4%) UC patients underwent colectomy, demonstrating cumulative proportions of surgery at 1, 5, and 10 years after diagnosis of 0.6%, 3.4%, and 8.2%, respectively. In addition, 23 (2.1%) UC patients were diagnosed with neoplasia, demonstrating cumulative proportions of neoplasia at 1, 5, and 10 years after diagnosis of 0.5%, 1.0%, and 3.5%, respectively.

CONCLUSIONS

Chinese UC patients had similar cumulative proportions of exposure to IBD-specific treatments but a lower surgical rate than patients in Western countries, indicating a different natural course, and close monitoring needs for UC in China. However, these results must be confirmed in population-based studies because the hospital-based cohort in our study might lead to selection bias.

Pathology and Clinical Significance of Inflammatory Bowel Disease-Associated Colorectal Dysplastic Lesions

Timely diagnosis and effective management of colorectal dysplasia play a vital role in preventing mortality from colorectal cancer in patients with chronic inflammatory bowel disease. This review provides a contemporary overview of the pathologic and endoscopic classification of dysplasia in inflammatory bowel disease, their roles in determining surveillance and management algorithms, and emerging diagnostic and therapeutic approaches that might further enhance patient management.

Risk and incidence of colorectal stricture progressing to colorectal neoplasia in patients with inflammatory bowel disease: a systematic review and meta-analysis

This study aims to assess the risk of colorectal stricture progressing to colorectal neoplasia (CRN) in patients with inflammatory bowel disease (IBD). The literature from PubMed, Embase, Web of Science, and Cochrane Library databases was searched from the date of databases' creation to 5 November 2022. The Newcastle-Ottawa Scale was used to evaluate the quality of the included literature. Meta-analysis was conducted using the Stata 15 software and R 4.04 software. Two case-control studies and 12 cohort studies were eventually included. Colorectal stricture in patients with IBD increased the risk of progressing to CRN [odds ratio (OR): 1.52, 95% confidence interval (CI): 1.02-2.29, P = 0.042], but was irrelevant to the risk of progressing to ACRN (OR: 3.56, 95% CI 0.56-22.70, P = 0.180). The risk of CRN were further distinguished in patients with ulcerative colitis (UC) and Crohn's disease (CD) Our findings showed that colorectal stricture may increase the risk of progressing to CRN in patients with UC (OR = 3.53, 95%CI 1.62-7.68, P = 0.001), but was irrelevant to the risk of progressing to CRN in patients with CD (OR = 1.09, 95% CI 0.54-2.21, P = 0.811). In conclusion, colorectal stricture in patients with IBD can be used as a risk factor for predicting CRN but cannot be used as a risk factor for predicting ACRN. Stricture is a risk factor for CRN in patients with UC but not in patients with CD. More prospective, multi-center studies with large samples are expected to confirm our findings.

Update on Endoscopic Dysplasia Surveillance in Inflammatory Bowel Disease

As medical management of inflammatory bowel disease makes great advances, most patients with inflammatory bowel disease will have long life expectancies without need for total colectomy. With prolonged disease duration, however, there is increased risk of dysplasia leading to colorectal cancer. Multiple consensus and guideline documents have been published over the last decade with recommendations to optimize early detection and management of dysplastic lesions. Endoscopic technology has improved tremendously, even over the past few years. Previously invisible dysplasia has become visible in most cases with advanced imaging technologies that now allow for much clearer and more detailed mucosal inspection. New tools to facilitate endoscopic resection of visible lesions have also enabled patients to avoid colectomy, with resulting need to continue colon surveillance. There are limited or conflicting data leading to inconsistent recommendations regarding the need for random biopsies, the preferred endoscopic imaging technique, and surveillance intervals after resection of dysplasia. Similarly, there remains significant variability in the application of guidelines into daily practice and availability of and training with advanced imaging technologies. Here, we present a narrative review of which patients are at highest risk for dysplasia, the current guidelines on surveillance colonoscopy, factors affecting optimal mucosal visualization, enhanced imaging techniques, standardized reporting terminologies for surveillance colonoscopy, endoscopic management of dysplasia, indications for colectomy, and briefly on future potential technologies to assist in dysplasia detection.