Faculty Bibliography

Studies assessing colonoscopic practice have demonstrated variation in adenoma detection rate,¹ detection rates of advanced adenomas,^2,3 and detection rates of sessile serrated lesions (SSLs).^4,5 Our aims were to study the patient-, provider-, and procedure-level variables associated with detection rates of adenoma, SSLs, and advanced neoplasia in screening colonoscopies performed in large community practice.

Patients with Barrett's esophagus (BE) are at increased risk of esophageal adenocarcinoma (EAC). The risk is largely based on the degree of dysplasia. Dysplasia cannot always be differentiated from inflammatory changes, and therefore may be classified as indefinite for dysplasia (IND). The risk of progressive dysplasia in patients with IND is unclear. Our aim is to characterize the risk of progression in US veterans with BE-IND. We performed a single-center retrospective cohort study of patients with BE-IND between 2006 and 2016. All IND was diagnosed by consensus conference with an expert gastrointestinal (GI) pathologist or review by an expert GI pathologist and persistence was defined as IND present on subsequent endoscopic biopsy. The primary outcome was the incidence rate of high-grade dysplasia (HGD)/EAC. Secondary outcomes included any progression including incident low-grade dysplasia (LGD), any prevalent dysplasia and risk factors for dysplastic progression, namely persistent IND. Risk factors for progression were assessed using univariate and multivariate analysis with logistic regression. Among 107 patients with BE-IND, there were no incident cases of HGD/EAC. Twenty patients (18.7%) developed incident LGD during a median follow-up of 2.39 years (interquartile range, 1.13-5.17). The annual rate of progression to LGD was 5.95 per 100 patient-years (95% CI, 3.73-9.02). Prevalent dysplasia was common (9.3%). Eight patients had prevalent LGD, one patient had prevalent HGD and one patient had prevalent EAC. Twenty-eight patients (30.1%) were found to have persistent IND. Among those with persistent IND, 10 (36%) patients progressed to LGD (none to HGD/EAC). The progression rate to LGD for patients with persistent IND was 7.86 (95% CI, 3.99-14.02) cases per 100 patient-years versus 4.78 (95% CI, 2.48-8.52) for nonpersistent IND (P = 0.036). The odds ratio for progression to LGD in persistent IND was 3.06 (95% CI, 1.08-8.64). In multivariate analysis adjusting for age, smoking history, presence of hiatal hernia and BMI > 30, persistent IND remained significant (OR 3.23; 95% CI, 1.04-9.98). Regression to nondysplastic BE was very common. Seventy-one (61%) patients developed complete and sustained regression of all dysplastic changes at last follow-up. Persistent IND, present in one-third of patients with IND, is an independent risk factor for progression to LGD. Although no patients in this cohort developed HGD/EAC, prevalent dysplasia was common (9.3%). Taken together, patients with IND should receive close surveillance for both prevalent and incident dysplasia especially if IND is persistent.

BACKGROUND:Aspirin is associated with decreased risk of colorectal cancer (CRC), potentially by modulating the gut microbiome. AIMS:To evaluate the effect of aspirin on the gut microbiome in a double-blinded, randomised placebo-controlled pilot trial. METHODS:Healthy volunteers aged 50-75 received a standard dose of aspirin (325 mg, N = 30) or placebo (N = 20) once daily for 6 weeks and provided stool samples every 3 weeks for 12 weeks. Serial measurements of gut microbial community composition and bacterial abundance were derived from 16S rRNA sequences. Linear discriminant analysis of effect size (LEfSe) was tested for between-arm differences in bacterial abundance. Mixed-effect regression with binomial distribution estimated the effect of aspirin use on changes in the relative abundance of individual bacterial taxa via an interaction term (treatment × time). RESULTS:Over the study period, there were differences in microbial composition in the aspirin vs placebo arm. After treatment, four taxa were differentially abundant across arms: Prevotella, Veillonella, Clostridium XlVa and Clostridium XVIII clusters. Of pre-specified bacteria associated with CRC (n = 8) or aspirin intake (n = 4) in published studies, interactions were significant for four taxa, suggesting relative increases in Akkermansia, Prevotella and Ruminococcaceae and relative decreases in Parabacteroides, Bacteroides and Dorea in the aspirin vs placebo arm. CONCLUSION:Compared to placebo, aspirin intake influenced several microbial taxa (Ruminococcaceae, Clostridium XlVa, Parabacteroides and Dorea) in a direction consistent with a priori hypothesis based on their association with CRC. This suggests that aspirin may influence CRC development through an effect on the gut microbiome. The findings need replication in a larger trial.

Colonoscopy is a safe and effective tool, but operator dependent. Room for improvement in the quality of colonoscopy is the impetus for the development and measurement of colonoscopy quality indicators and the focus of many efforts to improve colonoscopy quality indicator prevention and control in provider practices and health systems. We present the preprocedural, intraprocedural, and postprocedural quality indicators and benchmarks for colonoscopy. Every provider and practice must make a commitment to performing high-quality colonoscopy and implement and monitor quality metrics. There are a variety of tools available to assist in improving quality indicators that range from distal attachment devices to education and feedback. Although technology can help, it is not a substitute for proper technique. The commitment also requires provider feedback through audits and report cards. The impact of these efforts on patient outcomes is an important area of further research.