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.

Smoking and colorectal neoplasia in patients with inflammatory bowel disease: Dose-effect relationship

BACKGROUND AND AIMS

Prior studies on the effect of smoking on the risk of colitis-associated colorectal neoplasia (CRN) have reported conflicting results. We aimed to further elucidate the association between smoking, including possible dose-effects, and the development of colorectal neoplasia in patients with inflammatory bowel disease (IBD).

METHODS

We performed a prospective multicenter cohort study including patients with colonic IBD enrolled in a surveillance program in four academic hospitals between 2011 and 2021. The effects of smoking status and pack-years at study entry on subsequent recurrent events of CRN (including indefinite, low- and high-grade dysplasia, and colorectal cancer [CRC]) were evaluated using uni- and multivariable Prentice, Williams, and Peterson total-time Cox proportional hazard models. Adjustment was performed for extensive disease, prior/index dysplasia, sex, age, first-degree relative with CRC, primary sclerosing cholangitis, and endoscopic inflammation.

RESULTS

In 501 of the enrolled 576 patients, at least one follow-up surveillance was performed after the study index (median follow-up 5 years). CRN occurred at least once in 105 patients. Ever smoking was not associated with recurrent CRN risk (adjusted hazard ratio [aHR] 1.04, 95% confidence interval [CI] 0.75-1.44), but an increasing number of pack-years was associated with an increased risk of recurrent CRN (aHR per 10 pack-years 1.17, 95% CI 1.03-1.32; p < 0.05). Separate analyses per IBD type did not reveal differences.

CONCLUSIONS

This study found that an increase in pack-years is associated with a higher risk of recurrent CRN in patients with IBD, independent of established CRN risk factors (NCT01464151).

Surveillance and management of colorectal dysplasia and cancer in inflammatory bowel disease: Current practice and future perspectives

Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer (CRC). Current guidelines recommend frequent surveillance colonoscopies for patients with at least left-sided ulcerative colitis, or Crohn's disease involving more than 30% of the colon. Surveillance allows for early detection and treatment of colorectal dysplasia and cancer. The first colonoscopy should be performed 8 to 10 years after onset of disease symptoms. European and British guidelines employ a risk-stratification algorithm that assigns patients to surveillance intervals of one, three or five years, whereas American guidelines recommend to perform surveillance every 1 to 3 years based on the (combined) presence of risk factors. Patients with concomitant primary sclerosing cholangitis are at an additionally increased risk, and should undergo annual surveillance starting immediately after the diagnosis. The current practice of surveillance is based on limited evidence, is resource intensive and cannot preclude the occurrence of interval carcinomas. Fortunately, advances in endoscopic techniques for mucosal visualisation, along with better control of inflammation, have resulted in a declining incidence of CRC in patients with IBD. Furthermore, advanced endoscopic resection techniques can be expected to result in a shift from surgical to endoscopic management of dysplastic lesions. In this review, we provide an up-to-date overview of colitis-associated CRC pathophysiology, epidemiology, surveillance practices, and management of dysplasia.

Patients Prioritize a Low-volume Bowel Preparation in Colitis-associated Colorectal Cancer Surveillance: A Discrete Choice Experiment

BACKGROUND

Patients with inflammatory bowel disease (IBD) undergo surveillance colonoscopies at fixed intervals to reduce the risk of colorectal cancer (CRC). Taking patients' preferences for determining surveillance strategies into account could improve adherence and patient satisfaction. This study aimed to determine patient preferences for CRC surveillance in IBD.

METHODS

We conducted a web-based, multicenter, discrete choice experiment among adult IBD patients with an indication for surveillance. Individuals were repeatedly asked to choose between 3 hypothetical surveillance scenarios. The choice tasks were based on bowel preparation (0.3-4 L), CRC risk reduction (8% to 1%-6%), and interval (1-10 years). Attribute importance scores, trade-offs, and willingness to participate were calculated using a multinomial logit model. Latent class analysis was used to identify subgroups with similar preferences.

RESULTS

In total, 310 of 386 sent out questionnaires were completed and included in the study. Bowel preparation was prioritized (attribute importance score 40.5%) over surveillance interval and CRC risk reduction (31.1% and 28.4%, respectively). Maximal CRC risk reduction, low-volume bowel preparation (0.3 L laxative with 2 L clear liquid) with 2-year surveillance was the most preferred combination. Three subgroups were identified: a "surveillance avoidant," "CRC risk avoidant," and "surveillance preferring" groups. Membership was correlated with age, educational level, perceived CRC risk, the burden of bowel preparation, and colonoscopies.

CONCLUSIONS

Inflammatory bowel disease patients consider bowel preparation as the most important element in acceptance of CRC surveillance. Heterogeneity in preferences was explained by 3 latent subgroups. These findings may help to develop an individualized endoscopic surveillance strategy in IBD patients.

Prognostic Factors for Advanced Colorectal Neoplasia in Inflammatory Bowel Disease: Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal cancer (CRC). We performed a systematic review and meta-analysis to identify all prognostic factors for advanced colorectal neoplasia (aCRN, high-grade dysplasia, or CRC) in patients with IBD.

METHODS

A systematic literature search was conducted according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Risk of bias was assessed using the Quality in Prognostic Studies tool. Random-effects models were created separately for odds and hazard ratios, different study designs, and univariable or multivariable data. The evidence for all prognostic factors was categorized as "weak", "moderate", or "strong", based on estimate of effect sizes, heterogeneity, and risk of bias.

RESULTS

A total of 164 studies were included, allowing pooled analysis of 31 potential prognostic factors. In the univariable analysis, the evidence for extensive disease was classified as strong while evidence for low-grade dysplasia, strictures, primary sclerosing cholangitis, post-inflammatory polyps, family history of CRC, and ulcerative colitis versus Crohn's disease was considered moderate. Evidence for any dysplasia, colon segment resection, aneuploidy, male sex, and age was classified as weak. In addition, histologic inflammation was identified as a risk factor in multivariable analysis (weak evidence). The evidence for the protective factors colonoscopic surveillance, 5-Aminosalicylic Acid, thiopurines, and smoking was moderate in univariable analysis. Multivariable analysis provided weak evidence for statin use.

CONCLUSIONS

In this systematic review and meta-analysis, we identified 13 risk factors and 5 protective factors for aCRN in IBD patients, based on univariable and/or multivariable pooled analyses. These findings might lay the groundwork for an improved CRC risk stratification-based surveillance in IBD.