Navtej Buttar

Endoscopic and Surgical Treatment of Mucosal (T1a) Esophageal Adenocarcinoma in Barrett's Esophagus

BACKGROUND & AIMS Endoscopic therapy is emerging as an alternative to surgical therapy in patients with mucosal (T1a) esophageal adenocarcinoma (EAC) given the low likelihood of lymph node metastases. Long-term outcomes of patients treated endoscopically and surgically for mucosal EAC are unknown. We compared long-term outcomes of patients with mucosal EAC treated endoscopically and surgically. METHODS Patients treated for mucosal EAC between 1998 and 2007 were included. Patients were divided into an endoscopically treated group (ENDO group) and a surgically treated group (SURG group). Vital status information was queried using an institutionally approved internet research and location service. Statistical analysis was performed using Kaplan-Meier curves and Cox proportional hazard ratios. RESULTS A total of 178 patients were included, of whom 132 (74%) were in the ENDO group and 46 (26%) were in the SURG group. The mean follow-up period was 64 months (standard error of the mean, 4.8 mo) in the SURG group and 43 months (standard error of the mean, 2.8 mo) in the ENDO group. Cumulative mortality in the ENDO group (17%) was comparable with the SURG group (20%) (P = .75). Overall survival also was comparable using the Kaplan-Meier method. Treatment modality was not a significant predictor of survival on multivariable analysis. Recurrent carcinoma was detected in 12% of patients in the ENDO group, all successfully re-treated without impact on overall survival. CONCLUSIONS Overall survival in patients with mucosal EAC when treated endoscopically appears to be comparable with that of patients treated surgically. Recurrent carcinoma occurs in a limited proportion of patients, but can be managed endoscopically.

The Crosstalk of mTOR/S6K1 and Hedgehog Pathways

Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States. The TNF-α/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of the Hedgehog (HH) pathway, has been observed in EAC. In this study, we found that an activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by an mTOR pathway inhibitor enhances the killing effects of the HH pathway inhibitor. Together, our results established a crosstalk between the mTOR/S6K1 and HH pathways, which provides a mechanism for SMO-independent Gli1 activation and also a rationale for combination therapy for EAC.

Central Adiposity Is Associated With Increased Risk of Esophageal Inflammation, Metaplasia, and Adenocarcinoma: A Systematic Review and Meta-analysis

BACKGROUND & AIMS Central adiposity has been implicated as a risk factor for Barretts esophagus (BE) and esophageal adenocarcinoma (EAC), possibly promoting the progression from inflammation to metaplasia and neoplasia. We performed a systematic review and meta-analysis of studies to evaluate the association between central adiposity and erosive esophagitis (EE), BE, and EAC, specifically exploring body mass index (BMI)-independent and gastroesophageal reflux (GERD)-independent effects of central adiposity on the risk of these outcomes. METHODS We performed a systematic search of multiple databases through March 2013. Studies were included if they reported effect of central adiposity (visceral adipose tissue area, waist-hip ratio, and/or waist circumference) on the risk of EE, BE, and EAC. Summary adjusted odds ratio (aOR) estimates with 95% confidence intervals (CIs), comparing highest category of adiposity with the lowest category of adiposity, were calculated by using random-effects model. RESULTS Forty relevant articles were identified. Compared with patients with normal body habitus, patients with central adiposity had a higher risk of EE (19 studies; aOR, 1.87; 95% CI, 1.51-2.31) and BE (17 studies; aOR, 1.98; 95% CI, 1.52-2.57). The association between central adiposity and BE persisted after adjusting for BMI (5 studies; aOR, 1.88; 95% CI, 1.20-2.95). Reflux-independent association of central adiposity and BE was observed in studies that used GERD patients as controls or adjusted for GERD symptoms (11 studies; aOR, 2.04; 95% CI, 1.44-2.90). In 6 studies, central adiposity was associated with higher risk of EAC (aOR, 2.51; 95% CI, 1.54-4.06), compared with normal body habitus. CONCLUSIONS On the basis of a meta-analysis, central adiposity, independent of BMI, is associated with esophageal inflammation (EE), metaplasia (BE), and neoplasia (EAC). Its effects are mediated by reflux-dependent and reflux-independent mechanisms.

Direct Percutaneous Endoscopic Jejunostomy: Outcomes in 307 Consecutive Attempts

BACKGROUND:Clinical utilization of direct percutaneous endoscopic jejunostomy (DPEJ) is increasing. However, little data exist regarding important clinical outcomes with DPEJ.OBJECTIVE:To describe the indications, success, and complications of DPEJ in a large cohort of >300 consecutive attempted DPEJ cases at our institution.METHODS:Institutional databases identified 316 consecutive attempted DPEJ placements between January 1996 and August 2004. The medical records of consenting patients were abstracted for demographics, indication, success, complications, and follow-up. A scheme for classifying complication severity was designed.RESULTS:Three hundred and seven attempts at DPEJ were made on 286 patients. Of these, 209 succeeded (68%). The most common indications for DPEJ included resectable distal esophageal cancer, other malignancies causing obstruction, gastroparesis, prior esophageal or gastric resection, and high aspiration risk. Overall, 81 adverse events (AEs) were associated with DPEJ placement or removal in 69 (22.5%) cases. There were 14 serious AEs, 20 moderate AEs, and 47 mild AEs. Serious AEs included 7 bowel perforations, 3 jejunal volvuli, 3 major bleeds, and 1 aspiration. The only death was due to profound jejunal mesenteric bleeding after an unsuccessful trocar pass. Moderate AEs included 9 chronic enterocutaneous fistulae. Many of the 47 mild AEs were site infections requiring oral antibiotics (23) or persistent site pain (14).CONCLUSIONS:DPEJ was associated with a moderate or severe complication in ∼10% of cases. While DPEJ is a useful technique to gain enteral access that obviates the need for surgery and is more reliable than percutaneous gastrostomy with jejunal extension, patients and physicians should be aware of the risks involved.

Significance of Neoplastic Involvement of Margins Obtained by Endoscopic Mucosal Resection in Barrett's Esophagus

OBJECTIVES:Although EMR has been used for elimination of neoplasia in BE, the significance of positive carcinoma margins and depth of invasion on endoscopic resection pathology has not been assessed using a valid standard. The aim of this study was to assess the accuracy of tumor staging by EMR using esophagectomy as the standard.METHODS:Medical records of patients, who underwent endoscopic resection for esophageal carcinoma or high-grade dysplasia in BE followed by esophagectomy, were reviewed. Data were abstracted from a prospectively maintained EMR database. Endosonography and endoscopic resection were performed by a single experienced endoscopist. Two experienced GI pathologists interpreted all histological results. Standard statistical tests were used to compare continuous and categorical variables.RESULTS:Twenty-five patients were included in the study. Three patients had mucosal carcinoma and 16 had submucosal carcinoma following endoscopic resection. Surgical pathology staging was consistent with preoperative EMR staging in all patients. No patient with negative mucosal resection margins had residual tumor at the resection site at esophagectomy. In patients with submucosal carcinoma, 8 had residual carcinoma at the EMR site at surgery and 5 patients had metastatic lymphadenopathy.CONCLUSIONS:Tumor staging using EMR pathology is accurate when compared with surgical pathology following esophagectomy. Negative margins on EMR pathology correlate with absence of residual disease at the EMR site at esophagectomy. Submucosal carcinoma on EMR specimens was associated with a high prevalence of residual disease at surgery (50%) and metastatic lymphadenopathy (31%).

COX‐2 induction by unconjugated bile acids involves reactive oxygen species‐mediated signalling pathways in Barrett's oesophagus and oesophageal adenocarcinoma

Objectives: Bile reflux contributes to oesophageal injury and neoplasia. COX-2 is involved in both inflammation and carcinogenesis; however, the precise mechanisms by which bile acids promote COX-2 expression in the oesophagus are largely unknown. We analysed the molecular mechanisms that govern bile acid-mediated expression of COX-2 in Barrett’s oesophagus and oesophageal adenocarcinoma (OA). Design: The effects of bile acids on COX-2 expression were analysed in immortalised Barrett’s oesophagus and OA cells using immunoblotting and transient transfections. Pharmacological inhibitors, phospho-specific antibodies, dominant-negative mutants and siRNA techniques were used to identify relevant signalling pathways. Flow cytometry and reactive oxygen species (ROS) scavengers were used to examine ROS involvement. Immunohistochemistry was performed on oesophageal mucosa obtained from an established rat model of bile reflux. Results: Unconjugated bile acids potently stimulated COX-2 expression and induced AKT and ERK1/2 phosphorylation in concert with COX-2 induction. These findings were mimicked in the in vivo rat model. Dominant-negative (DN) AKT and LY294002 (PI3K inhibitor) or U0126 (MEK-1/2 inhibitor) blocked chenodeoxycholic acid (CD) and deoxycholic acid (DC) mediated COX-2 induction. CD and DC also induced CREB phosphorylation and AP-1 activity. CREB-specific siRNA and DN AP-1 blocked CD and DC-induced COX-2 induction. Finally, CD and DC increased intracellular ROS, while ROS scavengers blocked COX-2 induction and the signalling pathways involved. Conclusions: Unconjugated bile acids induce CREB and AP-1-dependent COX-2 expression in Barrett’s oesophagus and OA through ROS-mediated activation of PI3K/AKT and ERK1/2. This study enhances our understanding of the molecular mechanisms by which bile acids promote the development of oesophageal adenocarcinoma.

Utility of Biomarkers in Prediction of Response to Ablative Therapy in Barrett's Esophagus

BACKGROUND & AIMS Photodynamic therapy (PDT) has been shown to be effective in the treatment of high-grade dysplasia (HGD)/mucosal carcinoma in Barretts esophagus (BE). Substantial proportions of patients do not respond to PDT or progress to carcinoma despite PDT. The role of biomarkers in predicting response to PDT is unknown. We aimed to determine if biomarkers known to be associated with neoplasia in BE can predict loss of dysplasia in patients treated with ablative therapy for HGD/intramucosal cancer. METHODS Patients with BE and HGD/intramucosal cancer were studied prospectively from 2002 to 2006. Biomarkers were assessed using fluorescence in situ hybridization performed on cytology specimens, for region-specific and centromeric probes. Patients were treated with PDT using cylindric diffusing fibers (wavelength, 630 nm; energy, 200 J/cm fiber). Univariate and multiple variable logistic regression was performed to determine predictors of response to PDT. RESULTS A total of 126 consecutive patients (71 who underwent PDT and 55 patients who did not undergo PDT and were under surveillance, to adjust for the natural history of HGD), were included in this study. Fifty (40%) patients were responders (no dysplasia or carcinoma) at 3 months after PDT. On multiple variable analysis, P16 allelic loss (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.10-0.96) predicted decreased response to PDT. BE segment length (OR, 0.71; 95% CI, 0.59-0.85), and performance of PDT (OR, 7.17; 95% CI, 2.50-20.53) were other independent predictors of loss of dysplasia. CONCLUSIONS p16 loss detected by fluorescence in situ hybridization can help predict loss of dysplasia in patients with BE and HGD/mucosal cancer. Biomarkers may help in the selection of appropriate therapy for patients and improve treatment outcomes.

Prognostic Biomarkers for Esophageal Adenocarcinoma Identified by Analysis of Tumor Transcriptome

Background Despite many attempts to establish pre-treatment prognostic markers to understand the clinical biology of esophageal adenocarcinoma (EAC), validated clinical biomarkers or parameters remain elusive. We generated and analyzed tumor transcriptome to develop a practical biomarker prognostic signature in EAC. Methodology/Principal Findings Untreated esophageal endoscopic biopsy specimens were obtained from 64 patients undergoing surgery and chemoradiation. Using DNA microarray technology, genome-wide gene expression profiling was performed on 75 untreated cancer specimens from 64 EAC patients. By applying various statistical and informatical methods to gene expression data, we discovered distinct subgroups of EAC with differences in overall gene expression patterns and identified potential biomarkers significantly associated with prognosis. The candidate marker genes were further explored in formalin-fixed, paraffin-embedded tissues from an independent cohort (52 patients) using quantitative RT-PCR to measure gene expression. We identified two genes whose expression was associated with overall survival in 52 EAC patients and the combined 2-gene expression signature was independently associated with poor outcome (P<0.024) in the multivariate Cox hazard regression analysis. Conclusions/Significance Our findings suggest that the molecular gene expression signatures are associated with prognosis of EAC patients and can be assessed prior to any therapy. This signature could provide important improvement for the management of EAC patients.

Disruption of a Novel Krüppel-like Transcription Factor p300-regulated Pathway for Insulin Biosynthesis Revealed by Studies of the c.-331 INS Mutation Found in Neonatal Diabetes Mellitus

Krüppel-like transcription factors (KLFs) have elicited significant attention because of their regulation of essential biochemical pathways and, more recently, because of their fundamental role in the mechanisms of human diseases. Neonatal diabetes mellitus is a monogenic disorder with primary alterations in insulin secretion. We here describe a key biochemical mechanism that underlies neonatal diabetes mellitus insulin biosynthesis impairment, namely a homozygous mutation within the insulin gene (INS) promoter, c.-331C>G, which affects a novel KLF-binding site. The combination of careful expression profiling, electromobility shift assays, reporter experiments, and chromatin immunoprecipitation demonstrates that, among 16 different KLF proteins tested, KLF11 is the most reliable activator of this site. Congruently, the c.-331C>G INS mutation fails to bind KLF11, thus inhibiting activation by this transcription factor. Klf11−/− mice recapitulate the disruption in insulin production and blood levels observed in patients. Thus, these data demonstrate an important role for KLF11 in the regulation of INS transcription via the novel c.-331 KLF site. Lastly, our screening data raised the possibility that other members of the KLF family may also regulate this promoter under distinct, yet unidentified, cellular contexts. Collectively, this study underscores a key role for KLF proteins in biochemical mechanisms of human diseases, in particular, early infancy onset diabetes mellitus.

Contribution of intraoperative enteroscopy in the management of obscure gastrointestinal bleeding

Obscure gastrointestinal bleeding remains a significant diagnostic challenge. Our aims were (1) to determine the efficacy of intraoperative enteroscopy (IOE) in identifying lesions responsible for obscure gastrointestinal bleeding and (2) to determine the outcome of patients after treatment of these lesions. We retrospectively reviewed all patients who underwent IOE for obscure gastrointestinal bleeding from 1992 to 1998. Patients were divided into those with overt and those with occult gastrointestinal bleeding. Follow-up was complete in 67 patients (96%), with a median of 32 months (range 1 to 91 months). Seventy patients (52 overt and 18 occult) underwent IOE after extensive preoperative evaluation. Median duration of bleeding was 12 months, requiring a median of 14 blood transfusions. Risk factors for bleeding were identified in 46 patients (61 %). A lesion was identified and treated in 52 patients (74%)—39 in the overt group and 13 in the occult group. Lesions identified were vascular (54%), ulcerations (31%), tumors (11%), and small bowel diverticula (4%). Overall, 35 patients (52%) were found to have one or more lesions at IOE that were treated surgically and had no further bleeding. IOE, through a mid-small bowel enterotomy, has low morbidity and is effective in that it identified a treatable lesion in 74% of patients, which led to cure of bleeding in 52%.