Optimal tissue sampling during ERCP and emerging molecular techniques for the differentiation of benign and malignant biliary strictures

Patients with cholangiocarcinoma have poor survival since the majority of patients are diagnosed at a stage precluding surgical resection, due to locally irresectable tumors and/or metastases. Optimization of diagnostic strategies, with a principal role for tissue diagnosis, is essential to detect cancers at an earlier stage amenable to curative treatment. Current barriers for a tissue diagnosis include both insufficient tissue sampling and a difficult cyto- or histopathological assessment. During endoscopic retrograde cholangiopancreatography, optimal brush sampling includes obtaining more than one brush within an individual patient to increase its diagnostic value. Currently, no significant increase of the diagnostic accuracy for the new cytology brush devices aiming to enhance the cellularity of brushings versus standard biliary brush devices has been demonstrated. Peroral cholangioscopy with bile duct biopsies appears to be a valuable tool in the diagnostic work-up of indeterminate biliary strictures, and may overcome current technical difficulties of fluoroscopic-guided biopsies. Over the past years, molecular techniques to detect chromosomal instability, mutations and methylation profiling of tumors have revolutionized, and implementation of these techniques on biliary tissue during diagnostic work-up of biliary strictures may be awaited in the near future. Fluorescence in situ hybridization has already been implemented in routine diagnostic evaluation of biliary strictures in several centers. Next-generation sequencing is promising for standard diagnostic care in biliary strictures, and recent studies have shown adequate detection of prevalent genomic alterations in KRAS, TP53, CDKN2A, SMAD4, PIK3CA, and GNAS on biliary brush material. Detection of DNA methylation of tumor suppressor genes and microRNAs may evolve over the coming years to a valuable diagnostic tool for cholangiocarcinoma. This review summarizes optimal strategies for biliary tissue sampling during endoscopic retrograde cholangiopancreatography and focuses on the evolving molecular techniques on biliary tissue to improve the differentiation of benign and malignant biliary strictures.

Irritable Bowel Syndrome and Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Patients with microscopic colitis and patients with irritable bowel syndrome (IBS) present with similar symptoms. We examined the association between IBS and microscopic colitis in a systematic review and meta-analysis.

METHODS

We searched the medical literature to identify cross-sectional surveys or case-control studies reporting the association between microscopic colitis and IBS in 50 or more unselected adult patients. We recorded the prevalence of IBS symptoms in patients with histologically confirmed microscopic colitis, or the prevalence of histologically confirmed microscopic colitis in patients with IBS. Data were pooled using a random-effects model; the association between microscopic colitis and IBS was summarized using an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

The search strategy identified 3926 citations, of which 10 were eligible for our analysis. The pooled prevalence of IBS in patients with microscopic colitis was 33.4% (95% CI, 31.5%-40.6%), but was not significantly higher in patients with microscopic colitis than in patients with diarrhea (OR, 1.39; 95% CI, 0.43-4.47). In 3 cross-sectional surveys, the pooled OR for microscopic colitis in participants with IBS, compared with other patients with diarrhea, was 0.68 (95% CI, 0.44-1.04). In 4 case-control studies the prevalence of IBS in patients with microscopic colitis was significantly higher than in asymptomatic controls (OR, 5.16; 95% CI, 1.32-20.2).

CONCLUSIONS

Based on a meta-analysis, one third of patients with microscopic colitis reported symptoms compatible with IBS, but the prevalence of IBS was no higher than in other patients with diarrhea. The odds of microscopic colitis were no higher in patients with IBS compared with other patients with diarrhea. The value of routine colonoscopy and biopsy to exclude microscopic colitis in patients with typical IBS symptoms, unless other risk factors or alarm symptoms are present, remains uncertain.