CagA-positive strains of Helicobacter pylori may protect against Barrett's esophagus

Outcomes of Helicobacter pylori treatment in community practice and impact of therapeutic effectiveness information on physician behaviour

BACKGROUND

The effect of knowledge of Helicobacter pylori eradication rates on physician choice of treatment regimen is unknown. As practice variation results in differences in outcome, it is important to determine whether physician behaviour can be altered by such knowledge.

AIMS

(i) To determine whether dissemination of practice variation and effectiveness data regarding H. pylori changes subsequent prescribing behaviour and (ii) whether this change results in an improvement in the effectiveness of therapy.

METHODS

Community gastroenterologists in the Portland metropolitan area enrolled patients being treated for H. pylori. The regimen used, diagnostic method, indication and success in eradication was measured. Patient-centred factors were also measured, including symptoms, interest in post-treatment diagnostic testing and willingness to pay.

RESULTS

Significantly more physicians participating in both studies used proton pump inhibitor-triple therapy based regimens in this trial (46% vs. 85%, P=0.01), although the overall difference between the two trials was not significant (62% vs. 83%, P=0.11). There was no change in overall eradication rates by per protocol analysis between trials (84% vs. 85%, P=0.78), but a significant decrease in effectiveness by intention-to-treat analysis observed in this study (80% vs. 71%, P=0.03). Significantly more patients were treated for reasons other than peptic ulcer disease in this study (P=0.0003).

CONCLUSIONS

The overall effectiveness of H. pylori therapy in practice remains good. There has been a shift in the choice of treatment regimen and indication for therapy between the time periods of the two studies. Dissemination of treatment data appears to effect prescribing behaviour, but whether it has a beneficial effect on treatment outcome remains unproven.

Barrett esophagus

There continues to be great interest in Barrett esophagus, the premalignant lesion for adenocarcinoma of the esophagus and the esophagogastric junction. There were several publications this past year related to the epidemiology, pathogenesis, new methods for detection, biomarkers for stratifying patients by risk, and the treatment of patients with Barrett esophagus. Patients with intestinal metaplasia in short lengths of columnar mucosa in the distal esophagus (ie, short-segment Barrett esophagus) appear to be distinct from those with intestinal metaplasia in the gastric cardia. The reported risk of cancer in patients with Barrett esophagus is probably subject to publication bias, with small series reporting a higher incidence of cancer. New methods for the diagnosis and detection of intestinal metaplasia and dysplasia are being evaluated and may, in future, help in obtaining more accurate screening and more focused surveillance of patients with Barrett esophagus. The validation of biomarkers may help us to risk stratify patients at high risk for cancer development. Endoscopic mucosal resection appears to be a safe and effective technique for the resection and accurate diagnosis of dysplastic or cancerous areas within Barrett esophagus.

Gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a chronic disorder that affects millions of people worldwide and has the potential to lead to serious consequences, including cancer of the esophagus. It for this reason that there is such intense interest in the topic, this emphasized by the identification of some 341 articles published in the English language in the year 2000 alone. The present report highlights the results of a number of studies that either increase our understanding of the condition or raise important issues about its diagnosis and treatment. Included in the areas covered are (1) the role of genetics in GERD; (2) the mechanism for transient lower esophageal sphincter relaxations and their association with hiatal hernias; (3) the role of Helicobacter pylori in GERD and Barrett esophagus; (4) efficacy and safety of proton pump inhibitors in GERD; and (5) the mechanism for chronic cough in patients with GERD, among others.

The phenotype of gastric mucosa coexisting with Barrett's oesophagus

BACKGROUND/AIMS

Barrett's oesophagus complicates the gastro-oesophageal acid reflux. Helicobacter pylori infection, particularly with cagA positive strains, induces inflammatory/atrophic lesions of the gastric mucosa, which may impair acid output. No systematic study has investigated the phenotype of the gastric mucosa coexisting with Barrett's oesophagus. This study was designed to identify the phenotype of gastric mucosa associated with Barrett's oesophagus.

METHODS

In this retrospective case control study, the phenotype of the gastric mucosa was histologically characterised in 53 consecutive patients with Barrett's oesophagus and in 53 (sex and age matched) non-ulcer dyspeptic controls. Both patients and controls underwent extensive sampling of the gastric mucosa (two antral, one incisural, and two oxyntic biopsies). Intestinal metaplasia (IM) was categorised (type I, complete IM; types II and III, incomplete IM) by the high iron diamine stain; cagA status was ascertained by genotyping.

RESULTS

Helicobacter pylori was present in 19 of the 53 patients with Barrett's oesophagus and in 30 of the 53 controls (p < 0.02); eight of the 19 patients with Barrett's oesophagus and 28 of the 35 controls harboured cagA positive H pylori (p < 0.03). The histological severity of non-atrophic gastritis detected in the controls was significantly higher than that detected in the patients with Barrett's oesophagus (p < 0.0001). Multifocal atrophic gastritis was present in 4% of the patients with Barrett's oesophagus and in 23% of controls (p < 0.01). The odds ratio for the association between multifocal atrophic gastritis and Barrett's oesophagus was 0.20 (95% confidence interval, 0.006 to 0.60). Gastric IM was detected in 13.2% of the patients with Barrett's oesophagus and in 30.1% of the controls (p < 0.03). Type III IM at the gastric mucosa was only detected among controls.

CONCLUSIONS

Barrett's oesophagus is associated with a low prevalence of H pylori cagA positive infection and multifocal atrophic gastritis. This pathobiological pattern is considered to be associated with a low risk of distal gastric cancer.

Review article: should we kill or should we save Helicobacter pylori?

Results from epidemiological studies and therapeutic clinical trials have shown that Helicobacter pylori infection causes acute and chronic active gastritis and is the initiating factor for the majority of peptic ulcer disease. Eradication of the infection with antibiotics resolves gastritis and restores normal gastric physiology, accelerates healing of peptic ulcer disease, and virtually eliminates recurrence of duodenal ulcer disease. The infection also plays an important role in the initiation and/or progression of gastric atrophy and intestinal metaplasia, which may eventually lead to the development of distal gastric cancer. Furthermore, almost all patients with gastric MALT lymphoma are infected with H. pylori and cure of the infection leads to histological regression of the tumor and maintains the regression in over 80% of patients during long-term follow-up. Preliminary uncontrolled data from Japan show that eradication of the infection significantly reduced metachronous intestinal-type gastric cancer following initial endoscopic resection of early gastric cancer and might also prevent the progression of gastric adenoma to gastric dysplasia or gastric cancer. Although this overwhelming evidence has demonstrated that H. pylori infection is bad for humans, some have questioned the wisdom of eradicating the infection in all those infected. Their arguments are largely based on hypothesis and circumstantial evidence: 1) Less than 20% of all H. pylori infected persons will develop significant clinical consequences in their lifetime. 2) H. pylori strains are highly diverse at a genetic level and are of different virulence. 3) The antiquity of H. pylori infection in humans and their co-evolution suggests that H. pylori may be a commensal to humans. Eradication of H. pylori may remove some beneficial bacterial strains and may provoke esophageal disease or gastric cancer at the cardia. However, careful review of the literature confirms that H. pylori infection is a serious pathogen albeit in a minority of those infected. It remains for carefully designed prospective studies, rather than hypothesis to make changes in the current consensus position.

Achalasia

The optimal treatment of achalasia includes several options and presents a challenge for most gastroenterologists. There are numerous patient variables that must be assessed including age, degree of symptoms, duration of disease, desires of each patient, and related comorbidities. Treatment includes both medical and surgical options, with medical therapy further subclassified into pharmacologic and pneumatic dilation. Pneumatic dilations with a polyethylene dilator (sizes of 3.0, 3.5, and 4.0 cm) and laparoscopic myotomy represent the most common forms of therapy. A graduated increase in dilator size, based on symptomatic response, minimizes complications and is successful in more than 90% of patients. Further dilations or adjustment of pharmacologic therapy should be based on symptoms, weight gain, and a timed barium meal. Referral for myotomy should be considered for patients who do not respond to medical therapy or individuals that do not desire pneumatic dilations. Most patients responding to botulinum toxin (Botox; Allergan, Irvine, CA) injections will require repeat treatment at 3- to 6-month intervals. Due to cost constraints, Botox therapy should be reserved for patients who are at an increased risk from possible complications of a dilation or surgery, or those with less than 2 years of life expectancy. The most cost-effective course of therapy per patient cured over a 5-year period is pneumatic dilation, then Botox, and finally laparoscopic myotomy.