Gastroesophageal reflux disease and Barrett's esophagus

A Large-scale genetic association study of esophageal adenocarcinoma risk

The incidence of esophageal adenocarcinoma (EA) has been increasing rapidly, particularly among white males, over the past few decades in the USA. However, the etiology of EA and the striking male predominance is not fully explained by known risk factors. To identify susceptible genes for EA risk, we conducted a pathway-based candidate gene association study on 335 Caucasian EA cases and 319 Caucasian controls. A total of 1330 single-nucleotide polymorphisms (SNPs) selected from 354 genes were analyzed using an Illumina GoldenGate assay. The genotyped common SNPs include missense and exonic SNPs, SNPs within untranslated regions and 2 kb 5' of the gene, and tagSNPs for genes with little functional information available. Logistic regression adjusted for potential confounders was used to assess the genetic effect of each SNP on EA risk. We also tested gene-gender interactions using the likelihood ratio tests. We found that the genetic variants in the apoptosis pathway were significantly associated with EA risk after correcting for multiple comparisons. SNPs of rs3127075 in Caspase-7 (CASP7) and rs4661636 in Caspase-9 (CASP9) genes that play a critical role in apoptosis were found to be associated with an increased risk of EA. A protective effect of SNP rs572483 in the progesterone receptor (PGR) gene was observed among women carrying the variant G allele [adjusted odds ratio (OR) = 0.19; 95% confidence interval (CI) = 0.08-0.46] but was not observed among men (adjusted OR = 1.38; 95% CI = 0.95-2.00). In conclusion, this study suggests that the genetic variants of CASP7 and CASP9 in the apoptosis pathway may be important predictive markers for EA susceptibility and that PGR in the sex hormone signaling pathway may be associated with the gender differences in EA risk.

Polymorphisms of the NER pathway genes, ERCC1 and XPD are associated with esophageal adenocarcinoma risk

PURPOSE

Functional variation in DNA repair capacity through single nucleotide polymorphisms (SNPs) of key repair genes is associated with a higher risk of developing various types of cancer. Studies have focused on the nucleotide excision repair (NER) and base excision repair (BER) pathways. We investigated whether variant alleles in seven SNPs within these pathways increased the risk of esophageal adenocarcinoma.

METHODS

DNA was extracted from prospectively collected blood specimens. The samples were genotyped for SNPs in NER genes (XPD Lys751Gln, XPD Asp312Asn, ERCC1 8092C/A, and ERCC1 118C/T), and BER genes (XRCC1 Arg399Gln, APE1 Asp148Glu, and hOGG1 Ser326Cys). The presence of variant alleles was correlated with risk of esophageal adenocarcinoma both individually and jointly.

RESULTS

Variant alleles in NER SNPs XPD Lys751Gln (AOR = 1.50, 95% CI 1.1-2.0), ERCC1 8092 C/A (AOR = 1.44, 95% CI 1.1-1.9), and ERCC1 118C/T (AOR = 1.42, 95% CI 1.0-1.9) were individually associated with esophageal adenocarcinoma risk. An increasing number of variant alleles in NER SNPs showed a significant trend with esophageal adenocarcinoma risk (p = 0.007).

CONCLUSIONS

The presence of variant alleles in NER genes increases risk of esophageal adenocarcinoma. There is evidence of an additive role for SNPs along a common DNA repair pathway. Future larger studies of esophageal adenocarcinoma etiology should evaluate entire biological pathways.

Gastroesophageal reflux disease in pregnancy

Gastroesophageal reflux disease during pregnancy is common. Altered structure and function of the normal physiological barriers to reflux of gastric contents into the oesophagus explain the high incidence of this problem in pregnant women. For the majority of patients, life-style modifications are helpful, but are not sufficient to control symptoms and medication is required. The optimum management of reflux in pregnant patients requires special attention and expertise, since the safety of the mother, foetus and neonate remain the primary focus. Gastroenterologists and obstetricians should work together to optimise treatment. Typically, one utilises a step-up program that starts with life-style modifications and antacids. If those methods fail, histamine-2 receptor antagonists and proton pump inhibitors are tried. Rarely, promotility agents are used. Initiation of these medications must be undertaken after a careful discussion of risks and benefits with patients. In patients without a prior history of reflux, symptoms usually abate after delivery.

Laser Ablation Therapies for Barrett’s Esophagus

The metaplastic change of the normal squamous epithelium of the distal esophagus into a specialized columnar epithelium is known as Barrett's esophagus (BE) and is associated with an increased risk of adenocarcinoma of the esophagus. It is a frequent complication of gastroesophageal reflux disease (GERD) and up to 10% of patients with GERD suffer from BE. The progression to dysplasia increases the risk of cancer development and the annual risk of developing cancer in Barrett's esophagus is estimated to be 0.5% per year. The management of BE with high grade dysplasia (HGD) is controversial. Recent innovations in endoscopic therapy have allowed for the development of multiple endoscopic techniques, such as photodynamic therapy (PDT), argon plasma coagulation (APC), and endoscopic mucosal resection. In this article, we will discuss primarily photodynamic therapy, and other ablative technologies such as argon plasma coagulation in the treatment of BE.

The role of proton pump inhibitors in the treatment of heartburn during pregnancy

PURPOSE

To review the problem of heartburn in gravid women, discuss the present treatment options, and examine the use of proton pump inhibitors (PPIs) as one of the treatment options for moderate to severe heartburn.

DATA SOURCES

Extensive review of worldwide scientific literature on the use and safety of PPIs during pregnancy and heartburn during pregnancy.

CONCLUSIONS

Preliminary information indicates that use of PPIs during pregnancy is safe for both the fetus and the woman and that obstetrical practitioners are using them more frequently. Randomized controlled trials are needed to examine the efficacy of PPIs to treat heartburn during pregnancy, especially as they are compared to histamine(2) receptor antagonists.

IMPLICATIONS FOR PRACTICE

Heartburn during pregnancy is at risk for being undertreated, given that delivery is the cure. As PPIs are more widely used by women, questions will arise regarding their use in the first trimester as well as throughout pregnancy. This article brings nurse practitioners up to date on the safety of PPIs through the literature review and suggests various treatment options that can be discussed with the patient.

Clinical relevance of esophageal and gastric pH measurements in patients with gastro-esophageal reflux disease (GERD)

BACKGROUND

Gastro-esophageal reflux disease (GERD) is a highly prevalent disease caused by the exposure of the esophagus to refluxed gastric contents. Proton pump inhibitors (PPIs) are the mainstay of current treatment. At present, the assessment of the efficacy of different PPIs in the treatment of GERD employs two measures: esophageal and gastric pH monitoring. Esophageal pH monitoring is the most accurate method of detecting reflux episodes and, therefore, its role as a diagnostic modality is well accepted. Gastric pH monitoring, on the other hand, is an accurate measure of gastric acid pH, but its relevance to patients with GERD is questionable, since recordings correlate poorly with esophageal acid exposure.

OBJECTIVE

This paper reviews (based on a Medline literature search, 1980-2004) the clinical relevance of esophageal and gastric pH measurements in both the management of GERD and in the evaluation of the efficacy of PPI therapy.

FINDINGS AND CONCLUSIONS

Evidence presented suggests that the assessment of esophageal pH yields data of greater relevance to patients with GERD than does data from gastric pH. This largely arises from the fact that esophageal pH monitoring assesses the pH of the refluxate and the frequency of reflux episodes at the mucosal site affected by the disease. The use of esophageal pH monitoring is recommended in patients who fail to present with endoscopic evidence of esophagitis, those with extra-esophageal symptoms, those who have failed traditional anti-reflux therapies, and those who are potential candidates for anti-reflux surgery. In recent years, the technique has benefited from the development of a wireless pH probe, and there is also an increasing body of evidence supporting its use in combination with other emerging technologies, such as Bilitec monitoring and multichannel intraluminal impedance. Such an approach is anticipated to aid both the diagnosis of GERD and the characterization of gastro-esophageal reflux (GER) in these patients.

Argon plasma coagulation in Barrett's esophagus

Despite the availability of many clinical trials, there is no evidence that APC has any role in the management of Barrett's esophagus. Ablation therapy is not indicated for nondysplastic Barrett's esophagus (and this is true, whatever the technique used), and it should not be performed outside of a carefully designed and approved clinical trial. Indeed, these patients have a low risk of cancer, and there is no evidence that Barrett's esophagus ablation will be of any benefit for these patients. In some cases, APC could be of some help, especially for treating short segments of dysplastic Barrett's esophagus. In this field, however, it competes with the growing indication of mucosectomy, which clearly offers advantages in terms of treatment's quality control assessment.

What you need to know about Barrett's esophagus

The incidence of Barrett's esophagus is increasing and this diagnosis is being seen more frequently in endoscopy units. Barrett's esophagus is a premalignant condition where the cells that normally line the esophagus are replaced with specialized columnar cells. Patients with Barrett's require close surveillance to monitor their condition and screen for the development of esophageal adenocarcinoma. This article provides an overview of Barrett's esophagus to better prepare gastroenterology nurses for educating and caring for this population of patients. Included is a discussion of the pathophysiology, signs and symptoms, and diagnostics of this disease entity. Current treatment options including medical management with proton pump inhibitors, endoscopic mucosal ablation techniques such as photodynamic therapy, and surgical intervention are also discussed. Current patient education approaches are also discussed.