Emerging Insights into the Esophageal Microbiome

PURPOSE OF REVIEW

Analysis of the esophageal microbiome remains a relatively new field of research, and most studies to date have focused on characterizing the esophageal microbiome in states of health and disease. Microbiome alterations have been implicated in the pathogenesis of inflammatory and neoplastic conditions in the colon and elsewhere in the gastrointestinal tract. The epidemiology of various esophageal conditions including Barrett's esophagus (BE), esophageal adenocarcinoma (EAC), esophageal squamous cell carcinoma (ESCC), and eosinophilic esophagitis (EoE) point to the microbiome as a potential co-factor in disease pathogenesis, and the possibility exists that these microbiome alterations could contribute directly to the inflammatory environments necessary for the carcinogenesis or atopy involved in these conditions.

RECENT FINDINGS

The native esophageal microbiome is similar in composition to the oral microbiome, with a high relative abundance of the phylum Firmicutes and the genus Streptococcus. Limited studies to date suggest that there are certain microbiome alterations associated with esophageal diseases. Additionally, it may be possible to indirectly assess the esophageal microbiome via non-endoscopic means. This raises the possibility that non-invasive microbiome analysis could be used for disease screening and monitoring. Further understanding of the role of the esophageal microbiome in disease pathogenesis, as well as methods for microbiome alteration, may help elucidate future targets for disease modifying therapies, or minimally invasive screening tools in patients at high risk for development of various esophageal conditions.

Nitrous oxide cryotherapy for treatment of esophageal squamous cell neoplasia: initial multicenter international experience with a novel portable cryoballoon ablation system (with video)

BACKGROUND AND AIMS

Early esophageal squamous cell neoplasia (ESCN) can be successfully treated by EMR, endoscopic submucosal dissection (ESD), or radiofrequency ablation. A new portable, battery-powered cryotherapy system using nitrous oxide (cryoballoon focal ablation system [CbFAS]) has been used for Barrett's esophagus. It consists of a small hand-held device containing liquid nitrous oxide, which converts to gas within a low-pressure-compliant through-the-scope balloon and freezes targeted mucosa in contact with the balloon. This study evaluated the feasibility of endoscopic eradication of early ESCN with the CbFAS.

METHODS

Patients with early ESCN (defined as low-grade intraepithelial neoplasia [LGIN], high-grade intraepithelial neoplasia [HGIN], or early T1 squamous mucosal cancer) were treated with the CbFAS. After chromoendoscopy, all Lugol's unstained lesions (USLs) were targeted with 8, 10, or 12 seconds of ice per site, and treatment was repeated until biopsy samples demonstrated eradication of ESCN. Postprocedure adverse events were recorded.

RESULTS

Ten patients (4 men; median age, 69.5 years) with LGIN (n=2), HGIN (n=7), or esophageal squamous cell carcinoma (ESCC; n=1, after EMR) in 24 USLs were treated. The median maximum diameter of the largest USL was 1.5 cm (interquartile range, 1-2 cm), and median total length of all neoplastic USLs was 2 cm (range, 1-10 cm). Patients with focal disease received a median of 2 cryoablations, whereas 4 patients with large and/or multifocal circumferential neoplasia had 6 to 12 ablations per procedure. The median procedure time was 34 minutes (range, 18-57 minutes). Treatment was completed in all patients. No major adverse events occurred. Four patients developed mild self-limited chest pain requiring narcotic analgesics immediately after the procedure. Two patients who received circumferential ablation developed a stricture responding to dilation, with no recurrence. Complete endoscopic and pathologic response was achieved in all patients at 3 months. One year follow-up biopsy specimens in 7 patients showed no USL or ESCN. All patients were disease free at last visit, with a median follow-up time of 10.7 months (interquartile range, 4-14 months).

CONCLUSIONS

We report the first application of nitrous cryoballoon ablation for curative treatment of early primary or recurrent ESCN. Our initial experience suggests that efficacy is high and the safety profile is reasonable. Prospective trials are needed to optimize cryogen dosimetry and assess safety and efficacy.

Radiofrequency ablation for the treatment of weight regain after Roux-en-Y gastric bypass surgery

BACKGROUND AND AIMS

Roux-en-Y gastric bypass (RYGB) surgery is an established modality for the treatment of morbid obesity. However, approximately one-quarter of patients experience weight regain after initially successful weight loss. Endoscopic therapy targeting the gastric remnant pouch represents a novel potential strategy to re-induce weight loss in this population. We performed a pilot trial of radiofrequency ablation (RFA) of the gastric remnant pouch after RYGB to determine feasibility, safety, and efficacy for weight loss.

METHODS

We identified patients who had undergone RYGB, achieved >40% excess body weight loss (EBWL), and then regained >25% of lost weight. RFA was applied to the gastrojejunal anastomosis and the entire surface area of the gastric remnant pouch. Treatment was repeated at 4 and 8 months if patients did not meet specified weight loss targets. Weekly weights were obtained for 12 months. The primary efficacy outcome was percent EBWL at 12 months, compared with baseline.

RESULTS

Twenty-five patients were enrolled at 4 centers. Mean (± standard deviation [SD]) age was 45.4 ± 9.1 years, and 84% (21/25) were female. Mean (± SD) baseline body mass index was 40.2 ± 7.8. Twenty-two of 25 patients completed 12 months of follow-up. At 12 months, median (± SD) EBWL was 18.4% (interquartile ratio 10.8, 33.7; P < .0001). Significant weight loss was seen at 3.5 months (P < .0001) and at 7.5 months (P < .0001), with a significant trend for continued weight loss over the 12-month period (P = .013). Two patients had serious adverse events requiring hospitalization.

CONCLUSIONS

RFA of the gastric remnant pouch in patients with weight regain after RYGB resulted in significant reductions in excess body weight with an acceptable safety profile. Continued weight loss was observed after each RFA treatment. Further clinical trials in well-selected populations are warranted to determine the optimal number and frequency of RFA treatments and to assess durability of weight loss. (Clinical trial registration number: NCT01910688.).

Safety and efficacy of endoscopic spray cryotherapy for esophageal cancer

Although surgery is traditionally the standard of care for esophageal cancer, esophagectomy carries significant morbidity. Alternative endoscopic therapies are needed for patients who are not candidates for conventional treatment. The objective of this study is to assess the safety, efficacy, and tolerability of spray cryotherapy of esophageal adenocarcinoma. This study includes patients with esophageal adenocarcinoma who had failed or were not candidates for conventional therapy enrolled retrospectively and prospectively in an open-label registry and patients in a retrospective cohort from 11 academic and community practices. Endoscopic spray cryotherapy was performed until biopsy proven local tumor eradication or until treatment was halted due to progression of disease, patient withdrawal or comorbidities. Eighty-eight patients with esophageal adenocarcinoma (median age 76, 80.7% male, mean length 5.1 cm) underwent 359 treatments (mean 4.4 per patient). Tumor stages included 39 with T1a, 25 with T1b, 9 with unspecified T1, and 15 with T2. Eighty-six patients completed treatment with complete response of intraluminal disease in 55.8%, including complete response in 76.3% for T1a, 45.8% for T1b, 66.2% for all T1, and 6.7% for T2. Mean follow-up was 18.4 months. There were no deaths or perforations related to spray cryotherapy. Strictures developed in 12 of 88 patients (13.6%) but were present before spray cryotherapy in 3 of 12. This study suggests that endoscopic spray cryotherapy is a safe, well-tolerated, and effective treatment option for early esophageal adenocarcinoma.

Genomic regions associated with susceptibility to Barrett's esophagus and esophageal adenocarcinoma in African Americans: The cross BETRNet admixture study

Background

Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) are far more prevalent in European Americans than in African Americans. Hypothesizing that this racial disparity in prevalence might represent a genetic susceptibility, we used an admixture mapping approach to interrogate disease association with genomic differences between European and African ancestry.

Methods

Formalin fixed paraffin embedded samples were identified from 54 African Americans with BE or EAC through review of surgical pathology databases at participating Barrett’s Esophagus Translational Research Network (BETRNet) institutions. DNA was extracted from normal tissue, and genotyped on the Illumina OmniQuad SNP chip. Case-only admixture mapping analysis was performed on the data from both all 54 cases and also on a subset of 28 cases with high genotyping quality. Haplotype phases were inferred with Beagle 3.3.2, and local African and European ancestries were inferred with SABER plus. Disease association was tested by estimating and testing excess European ancestry and contrasting it to excess African ancestry.

Results

Both datasets, the 54 cases and the 28 cases, identified two admixture regions. An association of excess European ancestry on chromosome 11p reached a 5% genome-wide significance threshold, corresponding to -log₁₀(P) = 4.28. A second peak on chromosome 8q reached -log₁₀(P) = 2.73. The converse analysis examining excess African ancestry found no genetic regions with significant excess African ancestry associated with BE and EAC. On average, the regions on chromosomes 8q and 11p showed excess European ancestry of 15% and 20%, respectively.

Conclusions

Chromosomal regions on 11p15 and 8q22-24 are associated with excess European ancestry in African Americans with BE and EAC. Because GWAS have not reported any variants in these two regions, low frequency and/or rare disease associated variants that confer susceptibility to developing BE and EAC may be driving the observed European ancestry association evidence.

Transitional basal cells at the squamous-columnar junction generate Barrett's oesophagus

In several organ systems, the transitional zone between different types of epithelium is a hotspot for pre-neoplastic metaplasia and malignancy, but the cells of origin for these metaplastic epithelia and subsequent malignancies remain unknown. In the case of Barrett's oesophagus, intestinal metaplasia occurs at the gastro-oesophageal junction, where stratified squamous epithelium transitions into simple columnar cells. On the basis of a number of experimental models, several alternative cell types have been proposed as the source of this metaplasia but in all cases the evidence is inconclusive: no model completely mimics Barrett's oesophagus in terms of the presence of intestinal goblet cells. Here we describe a transitional columnar epithelium with distinct basal progenitor cells (p63⁺KRT5⁺KRT7⁺) at the squamous-columnar junction of the upper gastrointestinal tract in a mouse model. We use multiple models and lineage tracing strategies to show that this squamous-columnar junction basal cell population serves as a source of progenitors for the transitional epithelium. On ectopic expression of CDX2, these transitional basal progenitors differentiate into intestinal-like epithelium (including goblet cells) and thereby reproduce Barrett's metaplasia. A similar transitional columnar epithelium is present at the transitional zones of other mouse tissues (including the anorectal junction) as well as in the gastro-oesophageal junction in the human gut. Acid reflux-induced oesophagitis and the multilayered epithelium (believed to be a precursor of Barrett's oesophagus) are both characterized by the expansion of the transitional basal progenitor cells. Our findings reveal a previously unidentified transitional zone in the epithelium of the upper gastrointestinal tract and provide evidence that the p63⁺KRT5⁺KRT7⁺ basal cells in this zone are the cells of origin for multi-layered epithelium and Barrett's oesophagus.

Prophylaxis for Stress Ulcers With Proton Pump Inhibitors Is Not Associated With Increased Risk of Bloodstream Infections in the Intensive Care Unit

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) have been associated with increased risk of infection, likely because of changes in intestinal epithelial permeability and the gastrointestinal microbiome. PPIs are frequently given to patients in the intensive care unit (ICU) to prevent stress ulcers. These patients are at risk for bloodstream infections (BSIs), so we investigated the relationship between PPI use and BSIs among patients in the ICU.

METHODS

We performed a retrospective cohort study of adults (≥18 years) admitted to 1 of 14 ICUs within a hospital network of 3 large hospitals from 2008 through 2014. The primary exposure was PPI use for stress ulcer prophylaxis in the ICU. The primary outcome was BSI, confirmed by culture analysis, arising 48 hours or more after admission to the ICU. Subjects were followed for 30 days after ICU admission or until death, discharge, or BSI. Multivariable Cox proportional hazards modeling was used to test the association between PPIs and BSI after controlling for patient comorbidities and other clinical factors.

RESULTS

We analyzed data from 24,774 patients in the ICU, including 756 patients (3.1%) who developed BSIs while in the ICU. The cumulative incidence of BSI was 3.7% in patients with PPI exposure compared with 2.2% in patients without PPI exposure (log-rank test, P < .01). After adjusting for potential confounders, PPI exposure was not associated with increased risk of BSI while in the ICU (adjusted hazard ratio, 1.08; 95% confidence interval, 0.91-1.29). Comorbidities, antibiotic use, and mechanical ventilation were all independently associated with increased risk for BSIs.

CONCLUSIONS

In a retrospective study of patients in the ICU, administration of PPIs to prevent bleeding was not associated with increased risk of BSI. These findings indicate that concern for BSI should not affect decisions regarding use of PPIs in the ICU.

Receipt of Antibiotics in Hospitalized Patients and Risk for Clostridium difficile Infection in Subsequent Patients Who Occupy the Same Bed

OBJECTIVE

To assess whether receipt of antibiotics by prior hospital bed occupants is associated with increased risk for CDI in subsequent patients who occupy the same bed.

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective cohort study of adult patients hospitalized in any 1 of 4 facilities between 2010 and 2015. Patients were excluded if they had recent CDI, developed CDI within 48 hours of admission, had inadequate follow-up time, or if their prior bed occupant was in the bed for less than 24 hours.

MAIN OUTCOMES AND MEASURES

The primary exposure was receipt of non-CDI antibiotics by the prior bed occupant and the primary outcome was incident CDI in the subsequent patient to occupy the same bed. Incident CDI was defined as a positive result from a stool polymerase chain reaction for the C difficile toxin B gene followed by treatment for CDI. Demographics, comorbidities, laboratory data, and medication exposures are reported.

RESULTS

Among 100 615 pairs of patients who sequentially occupied a given hospital bed, there were 576 pairs (0.57%) in which subsequent patients developed CDI. Receipt of antibiotics in prior patients was significantly associated with incident CDI in subsequent patients (log-rank P < .01). This relationship remained unchanged after adjusting for factors known to influence risk for CDI including receipt of antibiotics by the subsequent patient (adjusted hazard ratio [aHR], 1.22; 95% CI, 1.02-1.45) and also after excluding 1497 patient pairs among whom the prior patients developed CDI (aHR, 1.20; 95% CI, 1.01-1.43). Aside from antibiotics, no other factors related to the prior bed occupants were associated with increased risk for CDI in subsequent patients.

CONCLUSIONS AND RELEVANCE

Receipt of antibiotics by prior bed occupants was associated with increased risk for CDI in subsequent patients. Antibiotics can directly affect risk for CDI in patients who do not themselves receive antibiotics.

Goblet Cell Ratio in Combination with Differentiation and Stem Cell Markers in Barrett Esophagus Allow Distinction of Patients with and without Esophageal Adenocarcinoma

The increasing incidence of esophageal adenocarcinoma (EAC) is mirrored by the increasing prevalence of Barrett esophagus, a precursor lesion resulting in a large number of individuals "at risk" for this lethal malignancy. Among patients with Barrett esophagus, only about 0.3% annually will develop EAC. Because large numbers of patients are followed in endoscopic surveillance, there is a need for risk prediction among a growing population of patients with Barrett esophagus. We identified four potential biomarkers from an inflammation (IL1β)-dependent mouse model of Barrett esophagus and tested them in 189 patients with Barrett esophagus with and without high-grade dysplasia (HGD)/early cancer (T1). The primary goal was to distinguish patients with Barrett esophagus with no evidence of dysplasia from those with dysplasia. Increasing stem cell marker LGR5 and niche cell marker DCLK1 and decreasing differentiation marker (secretory mucus cells, TFF2⁺ cells) correlated with elevated tumor score in the mouse. Having outlined the origin of those markers in the Barrett esophagus mouse model, we showed the applicability for human Barrett esophagus. We compared 94 patients with nondysplastic Barrett esophagus tissue with 95 patients with Barrett esophagus and HGD or early cancer. Low levels of TFF2 (AUC 87.2%) provided the best discrimination between nondysplastic Barrett esophagus and Barrett esophagus with cancer, followed by high levels of DCLK1 (AUC 83.4%), low goblet cell ratio (AUC 79.4%), and high LGR5 (AUC 71.4%). The goblet cell ratio, rather than the presence of goblet cells per se, was found to be an important discriminator. These findings may be useful in developing future risk prediction models for patients with Barrett esophagus and ultimately to improve EAC surveillance. Cancer Prev Res; 10(1); 55-66. ©2016 AACR.

Prediagnosis aspirin use and outcomes in a prospective cohort of esophageal cancer patients

BACKGROUND

Esophageal cancer remains associated with poor outcomes, yet little is known regarding factors that influence survival. Aspirin use prior to cancer diagnosis may influence outcomes. We aimed to assess the effects of prediagnosis aspirin use in patients with esophageal cancer.

METHODS

We conducted a prospective cohort study of newly-diagnosed esophageal cancer patients at two tertiary care centers. We assessed history of prediagnosis aspirin use, and prospectively followed patients and assessed mortality, cause of death, and development of metastases.

RESULTS

We enrolled 130 patients, the majority of whom were male (81.5%) and had adenocarcinoma (80.8%). Overall, 57 patients (43.9%) were regular aspirin users. In unadjusted analyses, we found no difference in all-cause mortality between aspirin users and nonusers. In multivariate analyses, prediagnosis aspirin use was not associated with all-cause mortality [hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.48-1.57] or esophageal cancer-specific mortality (HR 1.07, 95% CI 0.52-2.21). Prediagnosis aspirin use was associated with a significantly increased risk of interval metastasis (HR 3.59, 95% CI 1.08-11.96).

CONCLUSIONS

In our cohort of esophageal cancer patients, prediagnosis aspirin use was not associated with all-cause or cancer-specific mortality. However, risk of interval metastatic disease was increased among those who took aspirin regularly prediagnosis. Future studies are warranted to assess whether aspirin influences the molecular characteristics of esophageal tumors, with potential prognostic and therapeutic implications.

Potential Role of the Microbiome in Barrett's Esophagus and Esophageal Adenocarcinoma

Esophageal adenocarcinoma and its precursor Barrett's esophagus have been rapidly increasing in incidence for half a century, for reasons not adequately explained by currently identified risk factors such as gastroesophageal reflux disease and obesity. The upper gastrointestinal microbiome may represent another potential cofactor. The distal esophagus has a distinct microbiome of predominantly oral-derived flora, which is altered in Barrett's esophagus and reflux esophagitis. Chronic low-grade inflammation or direct carcinogenesis from this altered microbiome may combine with known risk factors to promote Barrett's metaplasia and progression to adenocarcinoma.

Abstract 2637: Impact of pre-diagnosis weight loss on outcomes in a prospective cohort of esophageal cancer patients

Background: Esophageal cancer survival rates remain extremely low and factors influencing outcomes for this malignancy are not well understood. Tumor cachexia is a poor prognostic factor for certain tumor types, but is not well-studied in esophageal cancer. Weight loss in esophageal cancer is likely multifactorial; it can be due to tumor cachexia as well as dysphagia from obstructing tumors. In this present study, we aimed to investigate the relationship between weight loss and overall survival in a cohort of esophageal cancer patients and to determine whether these associations differed with tumor size.

Methods: We prospectively enrolled subjects with recently diagnosed esophageal cancer at two tertiary care centers. Using a baseline questionnaire, we assessed demographics, medical history, medication use, and lifestyle factors. We recorded self-reported height and weight one year prior to and at diagnosis, which we used to calculate body mass index (BMI) and percent weight change, categorized by tertile. We ascertained from the medical records tumor characteristics including T stage (T1/2 or T3/4), location, pathology, and metastasis status, and collected follow-up data on treatment, imaging, and death. We used Cox regression to assess the association between percent weight loss and all-cause mortality.

Results: We included 134 subjects in the analyses, the majority of whom were male (81.3%) and had adenocarcinoma (82.1%). The median BMI one year prior to diagnosis was 28.3 (IQR 24.4 - 31.0) and median percent weight loss was 4.7% (IQR 0 - 10.9%). There was no association between BMI one year prior and all-cause mortality (HR 0.98, 95% CI 0.93 - 1.03). Increasing percent weight loss was associated with increased risk of all-cause mortality (unadjusted HR 2.74 for highest vs. lowest tertile, 95% CI 1.34 - 5.58, Ptrend = 0.005) and this remained significant when adjusted for BMI one year prior (HR 2.87 for highest vs. lowest tertile, 95% CI 1.40 - 5.89, Ptrend = 0.003). We found significant interaction between weight loss and T stage. Percent weight loss was significantly associated with all-cause mortality, adjusted for BMI one year prior, among patients with T stages 1 or 2 (HR 6.49 for highest vs. lowest tertile, 95% CI 1.30 - 32.4, Ptrend = 0.012), but not T stages 3 or 4 (HR 1.42 for highest vs. lowest tertile, 95% CI 0.54 - 3.71). In the final multivariable model, there remained a significant association between percent weight loss and all-cause mortality among patients with T stages 1 or 2 (HR 6.34 for highest vs. lowest tertile, 95% CI 1.22 - 33.1, Ptrend = 0.022).

Conclusions: In this cohort of esophageal cancer patients, we found that pre-diagnosis weight loss was associated with increased risk of all-cause mortality in patients with earlier stage tumors, independent of baseline BMI. We suspect that weight loss in early stage esophageal cancer may be due to tumor cachexia, a potential marker of more aggressive disease and worse prognosis.

Citation Format: Sherry Shen, James L. Araujo, Nasser K. Altorki, Joshua R. Sonett, Adriana Rodriguez, Kivilcim Sungur-Stasik, Alfred I. Neugut, Julian A. Abrams. Impact of pre-diagnosis weight loss on outcomes in a prospective cohort of esophageal cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2637.

Abstract 1705: CCK2R marks a gastrin-responsive stem cell that gives rise to Barrett's esophagus

The incidence of esophageal adenocarcinoma (EAC) has markedly increased in the United States over the last few decades. Barrett's esophagus (BE) is the most significant known risk factor for this malignancy. Barrett's metaplasia, a condition of esophagus characterized by a columnar-cell metaplasia that replaces the native squamous-cell epithelium is considered to be a complication of gastroesophageal reflux disease (GERD), another risk factor for EAC. The paradigm is that BE arises from an adaptation to the harsh intra-esophageal environment of chronic GERD, and predisposes to EAC. Other established risk factors for EAC include obesity, smoking, poor diet. Moreover, while BE patients often undergo periodic endoscopic examinations, screening for dysplasia has not been shown to decrease mortality and remains controversial.

Thus, a better understanding of the risk factors for BE progression is needed. The precise role of CCK2R in the gastric cardia and Barrett's esophagus has not been defined. CCK2R is upregulated in the esophagus in human BE and EAC, and real-time PCR of BE tissues indicated that the level of expression was 2x higher than that in esophageal tissues from normal control patients. CCK2R is upregulated in the gastric cardia of mice with Barrett's metaplasia, and this effect is enhanced with administration of bile acids, a key component of the refluxate.

In this study we used the L2-IL-1β model to determine whether CCK2R-expressing cells can give rise to BE, and whether inhibition of CCK2R could ameliorate the BE phenotype in our mouse model.

In order to understand the role of CCK2R-expressing cells in normal cardia, we performed lineage tracing studies in CCK2R-CreERT mice. We generated CCK2R-CreERT/TdTomato mice and induced them with tamoxifen at 6 weeks of age. Single Tomato-red positive cells became visible at the base of the cardia at 24 hours after induction. By days 2, 3, and 5 these Tomato-red cells expanded and moved upward in the cardia gland in contiguous fashion until almost all the cells in the gland were labeled. Tomato-red cells persisted for as long as one year in the cardia. Thus, CCK2R labels a progenitor cell in the normal gastric cardia whose progeny populate the gland and persist for at least one year, suggesting the ability to self-renew and consistent with a cardia stem cell.

Since CCK2R marks a proliferating progenitor cell in the cardia, we verified whether CCK2R also has functional importance in BE progression. We hypothesized that overexpression of gastrin, the ligand for CCK2R, could accelerate BE in L2-IL-1β mice. INS-GAS mice, which overexpress amidated gastrin under the transcriptional control of the insulin promoter, were crossed with L2-IL-1β mice. L2-IL-1β/INS-GAS mice treated with bile acids had significantly increased areas of BE involvement compared to L2-IL-1β or INS-GAS controls. No areas of BE were seen in wild type or INS-GAS mice treated with bile acids until the age of 12 months.

Citation Format: Aleksandra M. Urbanska, Yoomi Lee, Yoku Hayakawa, Julian A. Abrams, Michael Quante, Timothy C. Wang. CCK2R marks a gastrin-responsive stem cell that gives rise to Barrett's esophagus. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1705.

Proton pump inhibitors alter the composition of the gut microbiota

OBJECTIVE

Proton pump inhibitors (PPIs) are drugs used to suppress gastric acid production and treat GI disorders such as peptic ulcers and gastro-oesophageal reflux. They have been considered low risk, have been widely adopted, and are often over-prescribed. Recent studies have identified an increased risk of enteric and other infections with their use. Small studies have identified possible associations between PPI use and GI microbiota, but this has yet to be carried out on a large population-based cohort.

DESIGN

We investigated the association between PPI usage and the gut microbiome using 16S ribosomal RNA amplification from faecal samples of 1827 healthy twins, replicating results within unpublished data from an interventional study.

RESULTS

We identified a significantly lower abundance in gut commensals and lower microbial diversity in PPI users, with an associated significant increase in the abundance of oral and upper GI tract commensals. In particular, significant increases were observed in Streptococcaceae. These associations were replicated in an independent interventional study and in a paired analysis between 70 monozygotic twin pairs who were discordant for PPI use. We propose that the observed changes result from the removal of the low pH barrier between upper GI tract bacteria and the lower gut.

CONCLUSIONS

Our findings describe a significant impact of PPIs on the gut microbiome and should caution over-use of PPIs, and warrant further investigation into the mechanisms and their clinical consequences.

Linkage and related analyses of Barrett's esophagus and its associated adenocarcinomas

Background

Familial aggregation and segregation analysis studies have provided evidence of a genetic basis for esophageal adenocarcinoma (EAC) and its premalignant precursor, Barrett's esophagus (BE). We aim to demonstrate the utility of linkage analysis to identify the genomic regions that might contain the genetic variants that predispose individuals to this complex trait (BE and EAC).

Methods

We genotyped 144 individuals in 42 multiplex pedigrees chosen from 1000 singly ascertained BE/EAC pedigrees, and performed both model‐based and model‐free linkage analyses, using S.A.G.E. and other software. Segregation models were fitted, from the data on both the 42 pedigrees and the 1000 pedigrees, to determine parameters for performing model‐based linkage analysis. Model‐based and model‐free linkage analyses were conducted in two sets of pedigrees: the 42 pedigrees and a subset of 18 pedigrees with female affected members that are expected to be more genetically homogeneous. Genome‐wide associations were also tested in these families.

Results

Linkage analyses on the 42 pedigrees identified several regions consistently suggestive of linkage by different linkage analysis methods on chromosomes 2q31, 12q23, and 4p14. A linkage on 15q26 is the only consistent linkage region identified in the 18 female‐affected pedigrees, in which the linkage signal is higher than in the 42 pedigrees. Other tentative linkage signals are also reported.

Conclusion

Our linkage study of BE/EAC pedigrees identified linkage regions on chromosomes 2, 4, 12, and 15, with some reported associations located within our linkage peaks. Our linkage results can help prioritize association tests to delineate the genetic determinants underlying susceptibility to BE and EAC.

Predicting Barrett's Esophagus in Families: An Esophagus Translational Research Network (BETRNet) Model Fitting Clinical Data to a Familial Paradigm

BACKGROUND

Barrett's esophagus is often asymptomatic and only a small portion of Barrett's esophagus patients are currently diagnosed and under surveillance. Therefore, it is important to develop risk prediction models to identify high-risk individuals with Barrett's esophagus. Familial aggregation of Barrett's esophagus and esophageal adenocarcinoma, and the increased risk of esophageal adenocarcinoma for individuals with a family history, raise the necessity of including genetic factors in the prediction model. Methods to determine risk prediction models using both risk covariates and ascertained family data are not well developed.

METHODS

We developed a Barrett's Esophagus Translational Research Network (BETRNet) risk prediction model from 787 singly ascertained Barrett's esophagus pedigrees and 92 multiplex Barrett's esophagus pedigrees, fitting a multivariate logistic model that incorporates family history and clinical risk factors. The eight risk factors, age, sex, education level, parental status, smoking, heartburn frequency, regurgitation frequency, and use of acid suppressant, were included in the model. The prediction accuracy was evaluated on the training dataset and an independent validation dataset of 643 multiplex Barrett's esophagus pedigrees.

RESULTS

Our results indicate family information helps to predict Barrett's esophagus risk, and predicting in families improves both prediction calibration and discrimination accuracy.

CONCLUSIONS

Our model can predict Barrett's esophagus risk for anyone with family members known to have, or not have, had Barrett's esophagus. It can predict risk for unrelated individuals without knowing any relatives' information.

IMPACT

Our prediction model will shed light on effectively identifying high-risk individuals for Barrett's esophagus screening and surveillance, consequently allowing intervention at an early stage, and reducing mortality from esophageal adenocarcinoma. Cancer Epidemiol Biomarkers Prev; 25(5); 727-35. ©2016 AACR.

Safety and efficacy of endoscopic spray cryotherapy for esophageal cancer

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Background: Although surgery is traditionally the standard of care for esophageal cancer, esophagectomy carries significant morbidity and mortality. Alternative endoscopic therapies are needed for patients who are not candidates for conventional treatment. The objective of this study was to assess the safety, efficacy, and tolerability of spray cryotherapy of esophageal cancer. Methods: This study includes patients enrolled retrospectively and prospectively in an open-label registry and patients in a retrospective cohort from twelve academic and community practices. Endoscopic spray cryotherapy was performed until local tumor eradication was confirmed by biopsy or until treatment was halted due to progression of disease, patient withdrawal or co-morbidities. Results: One-hundred and eight patients (median age 75.5, 79.6% male, 93.5% adenocarcinoma, mean length 5.2 cm) underwent 442 treatments (mean 4.2 per patient). Tumor stages included 40 with T1a, 27 with T1b, 10 with unspecified T1, 15 with T2, and 16 with no T stage reported. One-hundred and six patients completed treatment with complete response of intraluminal disease in 54.7%, including complete response in 74.4% for T1a, 50% for T1b, 65.3% for all T1, 6.7% for T2, and 50% for those with no T stage reported. Mean follow-up was 17.3 months. There were no deaths or perforations related to spray cryotherapy. Strictures developed in 11 of 108 patients (10.2%) but were present before spray cryotherapy in 3 of 11. Conclusions: This study suggests that endoscopic spray cryotherapy is safe, well tolerated and effective for early esophageal cancer in patients who are not candidates for conventional therapy.

Treatment of Barrett's esophagus with a novel focal cryoablation device: a safety and feasibility study

BACKGROUND AND AIMS

Currently, eradication of Barrett's epithelium is preferably achieved using radiofrequency ablation (RFA) or spray cryoablation (SCA). However, both modalities suffer from drawbacks such as the need for sizing, multiple deployment steps, large controller units (RFA), imprecise dosing and need for gas-venting (SCA). The new Cryoballoon Focal Ablation System (CbFAS) may address these limitations. This study assessed the safety, feasibility, and dose response of the CbFAS in patients with flat Barrett's epithelium with or without dysplasia.

PATIENTS AND METHODS

In this multicenter, prospective non-randomized trial, 39 patients were each treated with one or two ablations of 6, 8, or 10 seconds. Symptoms were assessed immediately and 2 days post-cryoablation. Follow-up endoscopy was performed 6-8 weeks post-procedure to assess response. Outcome parameters were incidence of adverse events, pain, esophageal stricture formation, and ablation response by cryogen dose.

RESULTS

Of 62 ablations, 56 (10 with 6 seconds, 28 with 8 seconds, 18 with 10 seconds) were successfully performed. Six ablations failed because of device malfunction (n=3) and procedural or anatomic issues (n=3). Median procedure time was 7 minutes (interquartile range [IQR] 4-10). No major adverse events occurred; six patients experienced a minor mucosal laceration requiring no intervention. Mild pain was reported by 27% of patients immediately after cryoablation and by 14% after 2 days. No strictures were evident at follow-up.  Full squamous regeneration was seen in 47 treated areas (6 [60%] of the 6-second areas; 23 [82%] of the 8-second areas; 18 [100%] of 10-second areas).

CONCLUSIONS

Focal cryoablation of Barrett's epithelium with the CbFAS is feasible and safe, resulting in squamous regeneration in the majority of patients.

Phase Ib Randomized, Double-Blinded, Placebo-Controlled, Dose Escalation Study of Polyphenon E in Patients with Barrett's Esophagus

This study was conducted to determine the safety and efficacy of the green tea-derived Polyphenon E (Poly E) in patients with Barrett's Esophagus (BE). Subjects were randomized to a 6-month, twice daily (BID) oral treatment of placebo or Poly E (200, 400, or 600 mg). Endoscopic evaluation, including biopsies, was performed before and after treatment. The primary objective was to demonstrate safety; secondary objectives investigated catechin accumulation and effects in clinical specimens. Of the 44 enrolled subjects, 11 received placebo, and 33 received Poly E. No dose-limiting toxicities were encountered, and a maximum tolerated dose (MTD) was not reached. The recommended phase II dose was 600 mg twice daily. The most common treatment-related adverse events (AE) in Poly E-treated subjects were grade I and II nausea, grade I belching, and grade I lactate dehydrogenase (LDH) elevation. No treatment-related AEs were reported in placebo-treated subjects, aside from grade I laboratory abnormalities. Pill counts and subject diaries were not consistently collected, and compliance was difficult to determine. However, on the basis of an intention-to-treat analysis, there was a significant relationship between Poly E dose and esophageal EGCG level--mean changes (pmol/g) of 0.79 (placebo), 6.06 (200 mg), 35.67 (400 mg), and 34.95 (600 mg); P = 0.005. There was a possible relationship between Poly E dose and urine PGE-M concentration. In conclusion, Poly E was well-tolerated, and treatment with Poly E (400 and 600 mg) but not Poly E (200 mg) or placebo resulted in clinically relevant and detectable EGCG accumulation in the target organ, esophageal mucosa.

Immature myeloid progenitors promote disease progression in a mouse model of Barrett's-like metaplasia

Cdx2, an intestine specific transcription factor, is expressed in Barrett's esophagus (BE). We sought to determine if esophageal Cdx2 expression would accelerate the onset of metaplasia in the L2-IL-1β transgenic mouse model for Barrett's-like metaplasia. The K14-Cdx2::L2-IL-1β double transgenic mice had half as many metaplastic nodules as control L2-IL-1β mice. This effect was not due to a reduction in esophageal IL-1β mRNA levels nor diminished systemic inflammation. The diminished metaplasia was due to an increase in apoptosis in the K14-Cdx2::L2-IL-1β mice. Fluorescence activated cell sorting of immune cells infiltrating the metaplasia identified a population of CD11b+Gr-1+ cells that are significantly reduced in K14-Cdx2::L2-IL-1β mice. These cells have features of immature granulocytes and have immune-suppressing capacity. We demonstrate that the apoptosis in K14-Cdx2::L2-IL-1β mice is CD8+ T cell dependent, which CD11b+Gr-1+ cells are known to inhibit. Lastly, we show that key regulators of CD11b+Gr-1+ cell development, IL-17 and S100A9, are significantly diminished in the esophagus of K14-Cdx2::L2-IL-1β double transgenic mice. We conclude that metaplasia development in this mouse model for Barrett's-like metaplasia requires suppression of CD8+ cell dependent apoptosis, likely mediated by immune-suppressing CD11b+Gr-1+ immature myeloid cells.

Proton Pump Inhibitors Alter Specific Taxa in the Human Gastrointestinal Microbiome: A Crossover Trial

We conducted an open-label crossover trial to test whether proton pump inhibitors (PPIs) affect the gastrointestinal microbiome to facilitate Clostridium difficile infection (CDI). Twelve healthy volunteers each donated 2 baseline fecal samples, 4 weeks apart (at weeks 0 and 4). They then took PPIs for 4 weeks (40 mg omeprazole, twice daily) and fecal samples were collected at week 8. Six individuals took the PPIs for an additional 4 weeks (from week 8 to 12) and fecal samples were collected from all subjects at week 12. Samples were analyzed by 16S ribosomal RNA gene sequencing. We found no significant within-individual difference in microbiome diversity when we compared changes during baseline vs changes on PPIs. There were, however, significant changes during PPI use in taxa associated with CDI (increased Enterococcaceae and Streptococcaceae, decreased Clostridiales) and taxa associated with gastrointestinal bacterial overgrowth (increased Micrococcaceae and Staphylococcaceae). In a functional analysis, there were no changes in bile acids on PPIs, but there was an increase in genes involved in bacterial invasion. These alterations could provide a mechanism by which PPIs predispose to CDI. ClinicalTrials.gov ID NCT01901276.

Use of proton pump inhibitors is associated with fractures in young adults: a population-based study

Proton pump inhibitors (PPIs) are associated with risk for fracture in osteoporotic adults. In this population-based study, we found a significant association between PPIs and fracture in young adults, with evidence of a dose-response effect. Young adults who use PPIs should be cautioned regarding risk for fracture.

INTRODUCTION

Proton pump inhibitors (PPIs) are associated with fracture in adults with osteoporosis. Because PPI therapy may interfere with bone accrual and attainment of peak bone mineral density, we studied the association between use of PPIs and fracture in children and young adults.

METHODS

We conducted a population-based, case-control study nested within records from general medical practices from 1994 to 2013. Participants were 4-29 years old with ≥ 1 year of follow-up who lacked chronic conditions associated with use of long-term acid suppression. Cases of fracture were defined as the first incident fracture at any site. Using incidence density sampling, cases were matched with up to five controls by age, sex, medical practice, and start of follow-up. PPI exposure was defined as 180 or more cumulative doses of PPIs. Conditional logistic regression was used to estimate the odds ratio and confidence interval for use of PPIs and fracture.

RESULTS

We identified 124,799 cases and 605,643 controls. The adjusted odds ratio for the risk of fracture associated with PPI exposure was 1.13 (95% CI 0.92 to 1.39) among children aged < 18 years old and 1.39 (95% CI 1.26 to 1.53) among young adults aged 18-29 years old. In young adults but not children, we observed a dose-response effect with increased total exposure to PPIs (p for trend <0.001).

CONCLUSIONS

PPI use was associated with fracture in young adults, but overall evidence did not support a PPI-fracture relationship in children. Young adults who use PPIs should be cautioned regarding potentially increased risk for fracture, even if they lack traditional fracture risk factors.

Radiofrequency Ablation Is Associated With Decreased Neoplastic Progression in Patients With Barrett's Esophagus and Confirmed Low-Grade Dysplasia

BACKGROUND & AIMS

Barrett's esophagus (BE) with low-grade dysplasia (LGD) can progress to high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). Radiofrequency ablation (RFA) has been shown to be an effective treatment for LGD in clinical trials, but its effectiveness in clinical practice is unclear. We compared the rate of progression of LGD after RFA with endoscopic surveillance alone in routine clinical practice.

METHODS

We performed a retrospective study of patients who either underwent RFA (n = 45) or surveillance endoscopy (n = 125) for LGD, confirmed by at least 1 expert pathologist, from October 1992 through December 2013 at 3 medical centers in the United States. Cox regression analysis was used to assess the association between progression and RFA.

RESULTS

Data were collected over median follow-up periods of 889 days (interquartile range, 264-1623 days) after RFA and 848 days (interquartile range, 322-2355 days) after surveillance endoscopy (P = .32). The annual rates of progression to HGD or EAC were 6.6% in the surveillance group and 0.77% in the RFA group. The risk of progression to HGD or EAC was significantly lower among patients who underwent RFA than those who underwent surveillance (adjusted hazard ratio = 0.06; 95% confidence interval: 0.008-0.48).

CONCLUSIONS

Among patients with BE and confirmed LGD, rates of progression to a combined end point of HGD and EAC were lower among those treated with RFA than among untreated patients. Although selection bias cannot be excluded, these findings provide additional evidence for the use of endoscopic ablation therapy for LGD.

Use of Acid Suppression Medication is Associated With Risk for C. difficile Infection in Infants and Children: A Population-based Study

BACKGROUND

Acid suppression medication is associated with Clostridium difficile infection (CDI) in adults and is increasingly prescribed to children. This study evaluated the relationship between acid suppression medication and incident CDI in children.

METHODS

This was a population-based, nested case-control study. Patients were eligible if they were aged 0-17 years with 3 or more visits or 1 year or more of follow-up in the dataset. Patients were excluded if they had comorbidities that associate with CDI and might also associate with acid suppression medication. Patients with codes for CDI were matched 1:5 with control patients by age, sex, medical practice, time of entry into the dataset, and follow-up time. The primary exposure was use of acid suppression medication with proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) within 8-90 days.

RESULTS

We identified 650 CDI cases and 3200 controls. The adjusted odds ratio (OR) for CDI and acid suppression medication was 7.66 (95% confidence interval [CI], 3.24-18.1). Acid suppression medication was associated with CDI in infants aged <1 year (OR, 5.24; 95% CI, 1.13-24.4) and children aged 1-17 years (OR, 9.33; 95% CI, 3.25-26.8). There was increased risk for CDI with PPIs compared with H2RAs and with recent compared with distant exposure.

CONCLUSIONS

Acid suppression medication associated with CDI in infants and children in the outpatient setting, with an effect based on medication timing. Increased risk for CDI should be factored into the decision to use acid suppression medication in children.

Epidemiology of Barrett's Esophagus and Esophageal Adenocarcinoma

Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC), a disease with increasing burden in the Western world, especially in white men. Risk factors for BE include obesity, tobacco smoking, and gastroesophageal reflux disease (GERD). EAC is the most common form of esophageal cancer in the United States. Risk factors include GERD, tobacco smoking, and obesity, whereas nonsteroidal antiinflammatory drugs and statins may be protective. Factors predicting progression from nondysplastic BE to EAC include dysplastic changes on esophageal histology and length of the involved BE segment. Biomarkers have shown promise, but none are approved for clinical use.

The impact of proton pump inhibitors on the human gastrointestinal microbiome

Potent gastric acid suppression using proton pump inhibitors (PPIs) is common in clinical practice but may have important effects on human health that are mediated through changes in the gastrointestinal microbiome. In the esophagus, PPIs change the normal bacterial milieu to decrease distal esophageal exposure to inflammatory gram-negative bacteria. In the stomach, PPIs alter the abundance and location of gastric Helicobacter pylori and other bacteria. In the small bowel, PPIs cause polymicrobial small bowel bacterial overgrowth and have been associated with the diagnosis of celiac disease. In the colon, PPIs associate with incident but not recurrent Clostridium difficile infection.

Positive correlation between endoscopist radiofrequency ablation volume and response rates in Barrett's esophagus

BACKGROUND

Radiofrequency ablation (RFA) has become an accepted form of endoscopic treatment for Barrett's esophagus (BE), yet reported response rates are variable. There are no accepted quality measures for performing RFA, and provider-level characteristics may influence RFA outcomes.

OBJECTIVE

To determine whether endoscopist RFA volume is associated with rates of complete remission of intestinal metaplasia (CRIM) after RFA in patients with BE.

DESIGN

Retrospective analysis of longitudinal data.

SETTING

Three tertiary-care medical centers.

PATIENTS

Patients with BE treated with RFA.

INTERVENTION RFA MAIN OUTCOME MEASUREMENTS

For each endoscopist, we recorded RFA volume, defined as the number of unique patients treated as well as corresponding CRIM rates. We calculated a Spearman correlation coefficient relating these 2 measures.

RESULTS

We identified 417 patients with BE treated with RFA who had at least 1 post-RFA endoscopy with biopsies. A total of 73% of the cases had pretreatment histology of high-grade dysplasia or adenocarcinoma. The procedures were performed by 7 endoscopists, who had a median RFA volume of 62 patients (range 20-188). The overall CRIM rate was 75.3% (provider range 62%-88%). The correlation between endoscopist RFA volume and CRIM rate was strong and significant (rho = 0.85; P = .014). In multivariable analysis, higher RFA volume was significantly associated with CRIM (P for trend .04).

LIMITATIONS

Referral setting may limit generalizability. Limited number of endoscopists analyzed.

CONCLUSION

Endoscopist RFA volume correlates with rates of successful BE eradication. Further studies are required to confirm these findings and to determine whether RFA volume is a valid predictor of treatment outcomes in BE.

Cost-effectiveness of chemoprevention with proton pump inhibitors in Barrett's esophagus

BACKGROUND

Proton pump inhibitors (PPIs) may reduce the risk of esophageal adenocarcinoma (EAC) in patients with Barrett's esophagus. PPIs are prescribed for virtually all patients with Barrett's esophagus, irrespective of the presence of reflux symptoms, and represent a de facto chemopreventive agent in this population. However, long-term PPI use has been associated with several adverse effects, and the cost-effectiveness of chemoprevention with PPIs has not been evaluated.

AIM

The purpose of this study was to assess the cost-effectiveness of PPIs for the prevention of EAC in Barrett's esophagus without reflux.

METHODS

We designed a state-transition Markov microsimulation model of a hypothetical cohort of 50-year-old white men with Barrett's esophagus. We modeled chemoprevention with PPIs or no chemoprevention, with endoscopic surveillance for all treatment arms. Outcome measures were life-years, quality-adjusted life years (QALYs), incident EAC cases and deaths, costs, and incremental cost-effectiveness ratios.

RESULTS

Assuming 50% reduction in EAC, chemoprevention with PPIs was a cost-effective strategy compared to no chemoprevention. In our model, administration of PPIs cost $23,000 per patient and resulted in a gain of 0.32 QALYs for an incremental cost-effectiveness ratio of $12,000/QALY. In sensitivity analyses, PPIs would be cost-effective at $50,000/QALY if they reduce EAC risk by at least 19%.

CONCLUSIONS

Chemoprevention with PPIs in patients with Barrett's esophagus without reflux is cost-effective if PPIs reduce EAC by a minimum of 19%. The identification of subgroups of Barrett's esophagus patients at increased risk for progression would lead to more cost-effective strategies for the prevention of esophageal adenocarcinoma.

Abstract C48: Phase Ib randomized, double-blinded, placebo-controlled, dose escalation study of Polyphenon E in patients with Barrett's esophagus

Patients with Barrett's Esophagus (BE) have an increased risk of developing esophageal adenocarcinoma. Preclinical models of BE and esophageal cancer have demonstrated the antitumor activity of the green-tea derived Polyphenon E (Poly E) and identified potential biomarkers for following its activity in clinical specimens. We conducted a multicenter trial of Poly E in patients with BE with or without low-grade dysplasia. Subjects were randomized to a 6-month, twice daily (BID) treatment of either placebo or Poly E (200 mg, 400 mg, 600 mg dose cohorts). Endoscopic evaluation, including multiple biopsies, was performed at baseline and after treatment. The primary objective of this study was to demonstrate safety (i.e., determine the maximum tolerated dose (MTD). Secondary objectives investigated accumulation of Poly E catechin constituents (e.g., EGCG) in esophageal tissue and biologic effects of Poly E in clinical specimens, including high throughput effects on mucosal protein expression using functional proteomics.

Of the 44 randomized subjects, 11 received placebo, and 33 received Poly E (200 mg (6), 400 mg (7), 600 mg (20)). No dose-limiting toxicities were encountered, and the MTD was 600 mg BID. The most common treatment-related adverse events (AEs) reported in Poly E-treated subjects were grade 1-2 nausea (12%), grade 1 burping (6%), and grade 1 elevated serum LDH (6%). No treatment-related AEs were reported in placebo-treated subjects, aside from grade 1 laboratory abnormalities. Pill counts and daily patient diaries were not consistently collected, and compliance was difficult to determine for the majority of subjects. However, based on an intention-to-treat analysis there was a dose-exposure relationship (p=0.01, Spearman correlation test) between the dose of Poly E and EGCG levels in esophageal mucosa – mean changes (pmol/g) with treatment were 1.68 (placebo; n=9), 6.06 (200 mg; n=5), 31.66 (400 mg; n=6), and 30.86 (600 mg, n=10). There was a possible relationship between the dose of Poly E and urine PGEM concentration – mean urine PGEM concentrations (ng/mg creatinine) with treatment were 4.86 (placebo; n=9), 6.78 (200 mg; n=3), 9.02 (400 mg; n=5), and 7.89 (600 mg; n=11); however, this was not statistically significant. Treatment with Poly E or placebo did not reduce the length of Barrett's epithelium and did not lead to any statistically significant changes in mucosal protein expression. However, Poly E treatment may have affected the expression of stearoyl-CoA desaturase (SD1), PI3Kinase-alpha, and acetyl Coenzyme A Carboxylase (ACC); p-values ≥ 0.05, although false discovery rates were 0.93.

In conclusion, Poly E was well-tolerated in all dose cohorts, with only grade 1 AEs seen more commonly in Poly E-treated subjects. There were no apparent significant effects of treatment on either tissue histology or mucosal biomarker expression. However, treatment with Poly E (400 mg and 600 mg) but not Poly E (200 mg) or placebo resulted in clinically relevant and detectable EGCG accumulation in the target organ, esophageal mucosa. Clinical development of this compound may include a phase 2 trial of Poly E administered at the 600 mg BID dose for a longer duration.

Supported by NCI, DCP Contract N01-CN-035159 to the UT MD Anderson Early Phase Chemoprevention Consortium

Citation Format: Andrew K. Joe, Felice Schnoll-Sussman, Robert S. Bresalier, Julian A. Abrams, Hanina H. Hibshoosh, Kenneth Cheung, Richard A. Friedman, Chung S. Yang, Ginger Milne, Diane D. Liu, Kazeem Abdul, Michelle Bigg, Jessica Foreman, Shing Lee, Tao Su, Aqeel Ahmed, Alfred I. Neugut, Esther Akpa, Scott Lippman, Marjorie Perloff, Powel H. Brown, Charles J. Lightdale. Phase Ib randomized, double-blinded, placebo-controlled, dose escalation study of Polyphenon E in patients with Barrett's esophagus. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr C48.

Proton pump inhibitors and risk for recurrent Clostridium difficile infection among inpatients

OBJECTIVES

Observational studies suggest that proton pump inhibitors (PPIs) are a risk factor for incident Clostridium difficile infection (CDI). Data also suggest an association between PPIs and recurrent CDI, although large-scale studies focusing solely on hospitalized patients are lacking. We therefore performed a retrospective cohort analysis of inpatients with incident CDI to assess receipt of PPIs as a risk factor for CDI recurrence in this population.

METHODS

Using electronic medical records, we identified hospitalized adult patients between 1 December 2009 and 30 June 2012 with incident CDI, defined as a first positive stool test for C. difficile toxin B and who received appropriate treatment. Electronic records were parsed for clinical factors including receipt of PPIs, other acid suppression, non-CDI antibiotics, and comorbidities. The primary exposure was in-hospital PPIs given concurrently with C. difficile treatment. Recurrence was defined as a second positive stool test 15-90 days after the initial positive test. C. difficile recurrence rates in the PPI exposed and unexposed groups were compared with the log-rank test. Multivariable Cox proportional hazards modeling was performed to control for demographics, comorbidities, and other clinical factors.

RESULTS

We identified 894 inpatients with incident CDI. The cumulative incidence of CDI recurrence in the cohort was 23%. Receipt of PPIs concurrent with CDI treatment was not associated with C. difficile recurrence (hazard ratio (HR)=0.82; 95% confidence interval (CI)=0.58-1.16). Black race (HR=1.66, 95% CI=1.05-2.63), increased age (HR=1.02, 95% CI=1.01-1.03), and increased comorbidities (HR=1.09, 95% CI=1.04-1.14) were associated with CDI recurrence. In light of a higher 90-day mortality seen among those who received PPIs (log-rank P=0.02), we also analyzed the subset of patients who survived to 90 days of follow-up. Again, there was no association between PPIs and CDI recurrence (HR=0.87; 95% CI=0.60-1.28). Finally, there was no association between recurrent CDI and increased duration or dose of PPIs.

CONCLUSIONS

Among hospitalized adults with C. difficile, receipt of PPIs concurrent with C. difficile treatment was not associated with CDI recurrence. Black race, increased age, and increased comorbidities significantly predicted recurrence. Future studies should test interventions to prevent CDI recurrence among high-risk inpatients.

Clostridium difficile infection in the community: Are proton pump inhibitors to blame?

Once a nosocomial disease, Clostridium difficile infection (CDI) now appears frequently in the community in the absence of exposure to antibiotics. Prior studies have shown that patients with community-acquired CDI are younger, more likely to be female, and have fewer comorbidities compared to patients with hospital-associated CDI. Because most studies of CDI are hospital-based, comparatively little is known about community-acquired CDI. The recent study by Chitnis has received widespread attention because it used active surveillance to capture all cases of community-acquired CDI within a large population and assessed key risk factors. The authors found that low-level healthcare exposure and proton pump inhibitor use were common among those with non-antibiotics associated, community-acquired CDI. In this commentary, we discuss the changing epidemiology of community-acquired CDI and the evidence basis for the controversial association between proton pump inhibitors and community-acquired CDI.

Recurrence of esophageal intestinal metaplasia after endoscopic mucosal resection and radiofrequency ablation of Barrett's esophagus: results from a US Multicenter Consortium

BACKGROUND & AIMS

Radiofrequency ablation (RFA) is an established treatment for dysplastic Barrett's esophagus (BE). Although short-term end points of ablation have been ascertained, there have been concerns about recurrence of intestinal metaplasia (IM) after ablation. We aimed to estimate the incidence and identify factors that predicted the recurrence of IM after successful RFA.

METHODS

We analyzed data from 592 patients with BE treated with RFA from 2003 through 2011 at 3 tertiary referral centers. Complete remission of intestinal metaplasia (CRIM) was defined as eradication of IM (in esophageal and gastroesophageal junction biopsy specimens), documented by 2 consecutive endoscopies. Recurrence was defined as the presence of IM or dysplasia after CRIM in surveillance biopsies. Two experienced gastrointestinal pathologists confirmed pathology findings.

RESULTS

Based on histology analysis, before RFA, 71% of patients had high-grade dysplasia or esophageal adenocarcinoma, 15% had low-grade dysplasia, and 14% had nondysplastic BE. Of patients treated, 448 (76%) were assessed after RFA. Fifty-five percent of patients underwent endoscopic mucosal resection before RFA. The median time to CRIM was 22 months, with 56% of patients in CRIM by 24 months. Increasing age and length of BE segment were associated with longer times to CRIM. Twenty-four months after CRIM, the incidence of recurrence was 33%; 22% of all recurrences observed were dysplastic BE. There were no demographic or endoscopic factors associated with recurrence. Complications developed in 6.5% of subjects treated with RFA; strictures were the most common complication.

CONCLUSIONS

Of patients with BE treated by RFA, 56% were in complete remission after 24 months. However, 33% of these patients had disease recurrence within the next 2 years. Most recurrences were nondysplastic and endoscopically manageable, but continued surveillance after RFA is essential.

Diverging trends in the incidence of reflux-related and Helicobacter pylori-related gastric cardia cancer

GOALS

To describe historical incidence trends of 2 subtypes of gastric cardia cancer.

BACKGROUND

The incidence of gastric cardia cancer has increased in western countries. Prior studies have treated cardia cancer as a single entity, but recent data suggest that there are 2 distinct subtypes: reflux-related and Helicobacter pylori-related.

STUDY

We conducted a population-based study using Connecticut Tumor Registry data from 1955 to 2007. Age-adjusted incidence rates (per 100,000 person-years) were calculated for gastric cancer, as a whole and by anatomic subsite, and for esophageal adenocarcinoma. Cardia and noncardia cancer incidence rates were further adjusted to account for cases with unspecified subsite. Mathematical formulas were derived to calculate incidence rates for reflux-related and H. pylori-related cardia cancer.

RESULTS

The adjusted incidence of cardia cancer was 4.0 per 100,000 in 1955 to 1959, decreased to 2.4 per 100,000 in 1965 to 1969 before increasing to 3.4 per 100,000 by 2003 to 2007. The incidence of H. pylori-related cardia cancer decreased from 3.7 to 1.0 per 100,000 over the study period, whereas reflux-related cardia cancer increased progressively from 0.3 to 2.4 per 100,000. The curves for reflux-related cardia cancer and esophageal adenocarcinoma closely mirrored each other, and their combined incidence increased from 0.5 per 100,000 in 1955 to 1959 to 5.6 per 100,000 in 2003 to 2007.

CONCLUSIONS

The incidence of reflux-related cardia cancer has steadily increased, whereas H. pylori-related cardia cancer has declined progressively since the mid-20th century. Trends in reflux-related cardia cancer and esophageal adenocarcinoma incidence are very similar, suggesting that these 2 cancers share a similar etiology and pathophysiological process.

An automated tool for detecting medication overuse based on the electronic health records

PURPOSE

Medication overuse is a serious concern in healthcare as it leads to increased expenditures, side effects, and morbidities. Identifying overuse is only possible through excluding appropriate indications that are primarily mentioned in unstructured notes. We developed a framework for automatic identification of medication overuse and applied it to proton pump inhibitors (PPIs).

METHODS

We first created an indications knowledge base using data from drug labels, clinical guidelines, expert opinion, and other sources. We also obtained the list of current problems for 200 randomly selected inpatients who received PPIs using a natural language processing system and the discharge summaries of those patients. These problems were checked against the indications knowledge base to identify overuse candidates. Two gastroenterologists manually reviewed the notes and identified cases of overuse. Results from the automated framework were compared with the manual review.

RESULTS

Reviewers had high interrater reliability in finding indications (agreement = 92.1%, Cohen's κ = 0.773). In 137 notes included in the final analysis, our system identified indications with a sensitivity of 74% (95%CI = 59-86) and specificity of 95% (95%CI = 87-98). In cases of appropriate use where the automated system also found one or more indications, it always included the correct indication.

CONCLUSIONS

We created an automated system that can identify established indications of medication use in electronic health records with high accuracy. It can provide clinical decision support for identifying potential overuse of PPIs and could be useful for reducing overuse and encouraging better documentation of indications.

Barrett esophagus: what a mouse model can teach us about human disease

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the western world and accounts for 2% of all cancer-related deaths. The precursor lesion for EAC is Barrett esophagus (BE), which is strongly associated with gastresophageal reflux disease. A major limitation to the study of EAC has been the absence of tractable and genetically modifiable preclinical models of BE. A mouse model of BE and EAC that resembles human disease could provide novel insights into the origins and molecular pathogenesis of BE. In addition, validated animal models could help stratify BE patients given the limited predictive power of current standard endoscopic measures and clinical assessment. Here, we review the findings from recently developed mouse models of BE and EAC and their impact on clinical decision making, surveillance programs and therapeutic options. The data, taken together, suggest potential origins of BE from the gastric cardia, a role of bile acid and hypergatrinemia for carcinogenesis, a growing importance for columnar-like epithelium and a critical role for Notch signaling.

Folic acid increases global DNA methylation and reduces inflammation to prevent Helicobacter-associated gastric cancer in mice

BACKGROUND & AIMS

Previous studies have suggested that dietary folic acid (FA) can protect against certain types of cancers. However, the findings have varied, and the mechanisms by which FA exerts chemopreventive effects remain to be clarified. We examined the effects of FA supplementation on DNA methylation, gene expression, and gastric dysplasia in a transgenic mouse model that is etiologically and histologically well matched with human gastric cancers.

METHODS

Hypergastrinemic mice infected with Helicobacter felis were studied at multiple stages of gastric dysplasia and early cancer with FA supplementation initiated both at weaning and later in life. Global DNA methylation was assessed by a methylation sensitive cytosine incorporation assay, bisulfite pyrosequencing of B1 repetitive elements, and immunohistochemistry with anti-5-methylcytosine. We also profiled gene expression in the same tissues.

RESULTS

We found a decrease in global DNA methylation and tissue folate and an increase in serum homocysteine with progression of gastric dysplasia. FA supplementation prevented this loss of global DNA methylation and markedly reduced gastric dysplasia and mucosal inflammation. FA protected against the loss of global DNA methylation both in the dysplastic gastric epithelial cells and in gastric stromal myofibroblasts. In addition, FA supplementation had an anti-inflammatory effect, as indicated by expression profiling and immunohistochemistry for lymphocyte markers.

CONCLUSIONS

We conclude that FA supplementation is chemopreventive in this model of Helicobacter-associated gastric cancer. The beneficial effect of FA is likely due to its ability to prevent global loss of methylation and suppress inflammation.

Real-time increased detection of neoplastic tissue in Barrett's esophagus with probe-based confocal laser endomicroscopy: final results of an international multicenter, prospective, randomized, controlled trial

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) allows real-time detection of neoplastic Barrett's esophagus (BE) tissue. However, the accuracy of pCLE in real time has not yet been extensively evaluated.

OBJECTIVE

To compare the sensitivity and specificity of pCLE in addition to high-definition white-light endoscopy (HD-WLE) with HD-WLE alone for the detection of high-grade dysplasia (HGD) and early carcinoma (EC) in BE.

DESIGN

International, prospective, multicenter, randomized, controlled trial.

SETTING

Five tertiary referral centers.

PATIENTS

A total of 101 consecutive BE patients presenting for surveillance or endoscopic treatment of HGD/EC.

INTERVENTIONS

All patients were examined by HD-WLE, narrow-band imaging (NBI), and pCLE, and the findings were recorded before biopsy samples were obtained. The order of HD-WLE and NBI was randomized and performed by 2 independent, blinded endoscopists. All suspicious lesions on HD-WLE or NBI and 4-quadrant random locations were documented. These locations were examined by pCLE, and a presumptive diagnosis of benign or neoplastic (HGD/EC) tissue was made in real time. Finally, biopsies were taken from all locations and were reviewed by a central pathologist, blinded to endoscopic and pCLE data.

MAIN OUTCOME MEASUREMENTS

Diagnostic characteristics of pCLE.

RESULTS

The sensitivity and specificity for HD-WLE were 34.2% and 92.7%, respectively, compared with 68.3% and 87.8%, respectively, for HD-WLE or pCLE (P = .002 and P < .001, respectively). The sensitivity and specificity for HD-WLE or NBI were 45.0% and 88.2%, respectively, compared with 75.8% and 84.2%, respectively, for HD-WLE, NBI, or pCLE (P = .01 and P = .02, respectively). Use of pCLE in conjunction with HD-WLE and NBI enabled the identification of 2 and 1 additional HGD/EC patients compared with HD-WLE and HD-WLE or NBI, respectively, resulting in detection of all HGD/EC patients, although not statistically significant.

LIMITATIONS

Academic centers with enriched population.

CONCLUSIONS

pCLE combined with HD-WLE significantly improved the ability to detect neoplasia in BE patients compared with HD-WLE. This may allow better informed decisions to be made for the management and subsequent treatment of BE patients. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00795184.).

Barrett's esophagus: endoscopic treatments II

The following on endoscopic treatments of Barrett's esophagus includes commentaries on animal experiments on cryotherapy; indications for cryotherapy, choice of dosimetry, number of sessions, and role in Barrett's esophagus and adenocarcinoma; recent technical developments of RFA technology and long-term effects; the comparative effects of diverse ablation procedures and the rate of recurrence following treatment; and the indications for treatment of dysplasia and the role of radiofrequency ablation.

Chemoprevention of esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) is rising rapidly in Western countries, and effective chemoprevention for this malignancy is lacking. Endoscopic surveillance of patients with Barrett's esophagus is currently employed to diagnose EAC at earlier stages, but this strategy has several limitations. Non-steroidal anti-inflammatory drugs and proton pump inhibitors are the most promising agents for prevention of EAC, and a randomized controlled trial of aspirin and esomeprazole is ongoing. Other agents under investigation include green tea, berries, and antioxidants. Cost-effectiveness analyses have shown that chemopreventive agents need to be highly effective at preventing EAC in order to have benefit beyond endoscopic surveillance.

Detection of intestinal metaplasia after successful eradication of Barrett's Esophagus with radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) is an effective means of eradicating Barrett's esophagus (BE), both with and without associated dysplasia. Several studies have documented high initial success rates with RFA. However, there is limited data on IM detection rates after eradication.

AIMS

To determine the rate of detection of intestinal metaplasia (IM) after successful eradication of Barrett's esophagus.

METHODS

BE patients with and without dysplasia who had undergone RFA were retrospectively identified. Only those who had complete eradication as documented on the initial post-ablation endoscopy, and had minimum two surveillance endoscopies, were included in the analyses. Clinical, demographic, and endoscopic data were collected. Cumulative incidence of IM detection was calculated by the Kaplan-Meier method.

RESULTS

Forty-seven patients underwent RFA and had complete eradication of Barrett's epithelium. The majority of patients were male (76.6%), and the mean age was 64.2 years. The cumulative incidence of newly detected IM at 1 year was 25.9% (95% CI 15.1-42.1%). Dysplasia was detected at the time of recurrence in four patients, and all cases were detected at the GE junction in the absence of visible BE. Patients with recurrent IM had longer baseline segments of BE (median, 4 cm vs. 2 cm, p = 0.03).

CONCLUSIONS

The rate of detection of new IM is high in patients who have undergone successful eradication of BE by RFA. Additionally, dysplasia can recur at the GE junction in the absence of visible BE. Future studies are warranted to identify those patients at increased risk for the development of recurrent intestinal metaplasia.