© 2014 by the American College of Gastroenterology The American Journal of GastroenteroloGy

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The role of Thiopurines in reducing the need for Surgical resection in Crohn’s disease: a Systematic review and Meta-analysis

This meta-analysis from England examines whether thiopurine (TP) use reduces the risk of a first surgical resection in patients with Crohn’s disease. It has already been known that azathi-oprine and mercaptopurine have efficacy for inducing and maintaining remission in Crohn’s disease. In this meta-analysis, which incorporated 17 retrospective studies with 21,632 par-ticipants, the authors pooled hazard ratios representing 12,586 participants for the impact of TPs on risk of intestinal resection. The risk of intestinal resection in patients on TP was almost half that in the comparison group. Although this demonstrates significant efficacy, the authors point out that there remains quite a high proportion of patients with Crohn’s disease who will still require resection despite this therapy. See page 23

objective Manometric Criteria for the rumination Syndrome

This study from the Netherlands identifies objective criteria based on manometry with impedance monitoring that help to identify rumina-tion and differentiate it from the regurgitation that can occur in gastro-esophageal reflux disease (GERD). It is known that rumination results from abdominal wall contractions, leading to food regurgitation during or following meals. Although often regurgitation can be suspected on the basis of history, sometimes it may be difficult to differentiate from the free regurgitation associated with GERD. In this study, high-reso-lution manometry with pH and impedance monitoring was performed for 30 minutes after a meal. The authors identified the three variations of rumination: primary, secondary, and supragastric belch-induced. Furthermore, the diagnosis of rumination can be made when there is identification of free reflux of the proximal esophagus on impedance, combined with a dramatic intra-abdominal pressure increase of more than 30 mm Hg. The use of these criteria, developed with manometry

and impedance, during standard esophageal motility testing to identify rumination will probably require expansion of current esophageal laboratory procedures to specifically address the response to a meal. See page 52

effect of Helicobacter pylori eradication on Metachronous recurrence after endoscopic resection of Gastric neoplasmThis study from South Korea examined whether Helicobacter pylori eradication could impact the risk of metachronous gastric cancer following endoscopic resection of early cancer. This involved more than 1,000 patients who had early gastric cancer. Seventy-five patients had a recurrence of gastric cancer; within this group, those in whom H. pylori eradication was suc-cessful had a substantially lower risk of recurrence than did the subjects in whom H. pylori was not eradicated. This study supports a practice of aggressively attempting to eradicate H. pylori in patients with endoscopically resected early gastric cancer. See page 60

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The American Journal of GastroenteroloGy Volume 109 | JANuARY 2014 www.amjgastro.com

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In Vivo diagnostic accuracy of High-resolution Microendoscopy in differentiating neoplastic from non-neoplastic Colorectal Polyps: a Prospective Study

This study from the United States examines the accuracy of high-resolution microendoscopy (HRME) as a low-cost ‘optical biopsy’ technology. HRME allows for subcellular imaging and provides microscopic-level differentiation of tissue on examination. It is known that not all colon polyps are malignant or have malignant potential, and current techniques via colonoscopy do not allow for ready differentiation between neoplastic and non-neoplastic polyps. This study demonstrates that HRME had a very high accuracy (94%)

and high specificity for detection of neoplastic polyps. This is substantially better than the accuracy of standard white-light endos-copy, and this benefit occurred even with smaller diminutive polyps. A particular advantage of HRME is the relative simplicity and low cost of the technique. The endoscopists who participated in the study had relatively short training to identify the various types of HRME images. The broader application of this technology may allow for avoidance of the need to remove especially very small strongly hyperplastic polyps. See page 68

a Comprehensive analysis of Common Genetic Variation around Six Candidate loci for Intrahepatic Cholestasis of PregnancyThis study from multiple centers in Western Europe examines the somewhat mysterious intrahepatic cholestasis of pregnancy (ICP). Although it has been established that ICP has a significant genetic component, little is known about how common genetic variants influ-ence disease risk. This study identified three common variants in two genes that have a substantial impact on the susceptibility of preg-nant women to ICP, as well as a new independent risk locus in the ABCB11 gene. The investigators were able to confirm these findings in a second cohort of patients. How these genetic variants cause disease is not entirely clear, but the ABCB11 locus contains the bile salt export pump, which could well play a role in ICP. It may be possible in the future to predict from the gene variants whether treatment, such as with ursodeoxycholic acid, may benefit these patients. See page 76

differential effects of FodMaPs (Fermentable oligo-, di-, Mono-Saccharides and Polyols) on Small and large Intestinal Contents in Healthy Subjects Shown by MrIFODMAPs are thought to exacerbate symptoms in patients with irrita-ble bowel syndrome (IBS). This study examined the effects of fructose, the polymeric sugar inulin, and glucose with or without fructose on small intestinal water content and colonic gas. The investigators used hydrogen breath test responses as well as magnetic resonance imaging (MRI) to examine the changes in small intestinal water content and colonic gas in healthy volunteers. They were able to demonstrate that fructose and fructans appear to be poorly absorbed within the small intestine. Fructose, in particular, leads to marked distention of the small intestine with water, probably due to its osmotic effect. Inulin, a prototypical fructan, is not at all absorbed in the small intestine and is fermented in the colon, resulting in substantial colonic distention with gas. The effect of fructose on small-bowel water content was mitigated when it was coadministered with glucose. This combination occurs naturally with sucrose. Imaging demonstrated an increase in small-bowel diameter with each of the FODMAP stimuli. This study provides intriguing though not entirely surprising documentation of the differential effects of FODMAPs on the small intestine and colon in healthy individuals. One can logically extrapolate this to the likely symptom generation that could occur in patients with IBS, who would be inherently sensitive to the distention of the small intestine with water or of the colon with gas. Further studies in patients with IBS are awaited with interest. See page 110

Hyperplastic polyp Sessile serrated adenoma Tubular adenoma

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© 2014 by the American College of Gastroenterology The American Journal of GastroenteroloGy

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Prediction of Malignancy in Cystic neoplasms of the Pancreas: a Population-Based Cohort StudyWith high-resolution body imaging becoming increasingly com-mon, incidental cystic neoplasms of the pancreas are being found with increasing frequency. It is recognized that only a small subset of these pancreatic cysts will develop malignancy, and ways of stratify-ing the malignant potential of these lesions are urgently needed. This population-based cohort from southern California demonstrates that most of the malignancies are detected when cysts are first diag-nosed. Subsequent malignancies in the pancreas in this cohort are relatively rare, occurring at a rate of just 0.4% per year. However, despite this low subsequent incidence, when adjusted for age and sex, the risk is still 35 times greater than in the general population. Also, the risk for malignancy could be determined via the usual imaging criteria, including size, dilatation of the main pancreatic duct, features of serous cystadenoma, and growth during the period of surveillance. See page 121

Cyst Cohortn=1815

Size<3 cmn=1444

Size 1–3 cmn=1116

No duct dilatationn=1057

No growthn=998

Features of SCAn=17

0.0% malignant

Main duct dilatationn=59

13.6% malignant

Cyst growthn=59

5.1% malignant

Size 1–2 cmn=682

0.6% malignant

Size 2–3 cmn=316

1.3% malignant

No features of SCAn=354

9.3% malignant

Size<1 cmn = 328

0.3% malignant*

Size�3 cmn=371