Human gastric carcinoid detected during long-term antiulcer therapy of H2 receptor antagonist and proton pump inhibitor

Proton Pump Inhibitors and Cancer Risk: A Comprehensive Review of Epidemiological and Mechanistic Evidence

Background: Proton pump inhibitors (PPIs) are commonly prescribed long-acting drugs used to treat acid reflux, gastroesophageal reflux disease (GERD), and peptic ulcers. Recently, concerns have been raised about their safety, particularly due to the association between long-term PPI use and cancer development. Multiple comprehensive studies have consistently suggested a noteworthy link between prolonged PPI usage and an increased risk of developing gastric, esophageal, colorectal, and pancreatic cancers, yet the precise underlying mechanism remains elusive. Methods: First, we review the extensive body of research that investigates the intricate relationship between cancer and PPIs. Then, we predict PPI toxicity using the prodrug structures with the ProTox-II webserver. Finally, we predict the relative risk of cancer for each PPI, using PubMed citation counts of each drug and keywords related to cancer. Results: Our review indicates that prolonged PPI use (exceeding three months) is significantly associated with an elevated risk of cancer, while shorter-term usage (less than three months) appears to pose a comparatively lower risk. Our review encompasses various proposed mechanisms, such as pH and microbiome alterations, vitamin and mineral malabsorption, hypergastrinemia, and enterochromaffin-like cell proliferation, while ProTox-II also suggests aryl hydrocarbon receptor binding. Potentially, the PubMed citations count suggests that the PPIs omeprazole and lansoprazole are more associated with cancer than pantoprazole and esomeprazole. In comparison, the H2R blocker, famotidine, is potentially less associated with cancer than PPIs, and may serve as a safer alternative treatment for periods beyond 3 months. Conclusions: Despite the well-established cancer risk associated with PPIs, it is notable that these medications continue to be widely prescribed for periods longer than 3 months. Thus, it is of paramount importance for clinicians and patients to thoughtfully evaluate the potential risks and benefits of long-term PPI usage and explore alternative treatments before making informed decisions regarding their medical management.

Current understanding of pathogenetic mechanisms in neuroendocrine neoplasms

INTRODUCTION

Despite the fact that important advances in research on neuroendocrine neoplasms (NENs) have been made, consistent data about their pathogenetic mechanism are still lacking. Furthermore, different primary sites may recognize different pathogenetic mechanisms.

AREAS COVERED

This review analyzes the possible biological and molecular mechanisms that may lead to NEN onset and progression in different organs. Through extensive research of the literature, risk factors including hypercholesterolemia, inflammatory bowel disease, chronic atrophic gastritis are evaluated as potential pathogenetic mechanisms. Consistent evidence is available regarding sporadic gastric NENs and MEN1 related duodenopancreatic NENs precursor lesions, and genetic-epigenetic mutations may play a pivotal role in tumor development and bone metastases onset. In lung neuroendocrine tumors (NETs), diffuse proliferation of neuroendocrine cells on the bronchial wall (DIPNECH) has been proposed as a premalignant lesion, while in lung neuroendocrine carcinoma nicotine and smoke could be responsible for carcinogenic processes. Also, rare primary NENs such as thymic (T-NENs) and Merkel cell carcinoma (MCC) have been analyzed, finding different possible pathogenetic mechanisms.

EXPERT OPINION

New technologies in genomics and epigenomics are bringing new light to the pathogenetic landscape of NENs, but further studies are needed to improve both prevention and treatment in these heterogeneous neoplasms.

How safe are heartburn medications and who should use them?

INTRODUCTION

Heartburn is a frequent symptom occurring in daily clinical practice and is mainly associated with gastroesophageal reflux disease (GERD). However, it can be stimulated by various factors and diseases other than GERD can present with heartburn. Therefore, physicians must be very careful in distinguishing GERD from non-GERD conditions in their patients, particularly when heartburn is refractory to anti-reflux medications.

AREAS COVERED

The aim of this narrative review was to analyze the medical literature regarding the prevalence of heartburn and the various clinical disorders which can be present with this symptom. The type of medications usually adopted for treating heartburn and their grade of safety have been reviewed using an extensive computerized (Medline/PubMed) search with particular focus on the last 20 years.

EXPERT OPINION

Many drugs can be used for relieving heartburn in patients with GERD, although PPIs are the pharmacological agents with the greatest efficacy. However, it must be highlighted that many non-GERD conditions may present clinically with this symptom whose intensity does not differ between GERD and functional esophageal disorders, which represent about 50% of all patients with suspected GERD. It is very important to identify these functional conditions because their treatment differs completely from that of GERD.

The First Case of Gastric Neuroendocrine Tumors Induced by a Proton Pump Inhibitor in von Hippel-Lindau Disease

Von Hippel-Lindau (VHL) disease is a rare inherited familial syndrome complicated with various neoplasms, including neuroendocrine tumors (NETs). We herein report the first case of multiple gastric NETs in a 45-year-old man with VHL. He had multiple gastric polyps, and several endoscopic resected lesions were diagnosed as NETs. The serum gastrin level was elevated because he was taking a proton pump inhibitor (PPI). We suspected that gastrin had played a role in the development of NETs, and the remaining polyps were followed up with discontinuation of the PPI. The NETs gradually reduced in size until they became hard to notice on endoscopy and have remained nearly invisible for over eight years.

Gastroprotective Effects of Fermented Gold Kiwi (Actinidia chinenesis L.) Extracts on HCl/EtOH-Induced Gastric Injury in Rats

Gastritis and gastric ulcers caused by stressors such as drinking are common. The ability of functional foods to protect the stomach more effectively and reduce the risk of side effects is of interest. The fermentation process can increase the preservation and bioactive compound content of kiwi fruits. This study produced fermented kiwi powder using two lactic acids separated from gold kiwi fruits. Gold kiwi puree (Actinidia chinensis L.) was fermented using beneficial bacteria. Fermentation increased the content of bioactive compounds such as organic acids, flavonoids, and carotenoids. We investigated whether fermented gold kiwi (FGK) extract had antioxidant and gastric protective effects in an HCl/EtOH-induced gastritis animal model and pyloric ligation animal model. FGK increased radical scavenging activity in a dose-dependent manner. In the gastritis model, FGK inhibited inflammation-related factors such as iNOS, COX-2, IL-6, and TNF-α, while increasing the expression of the protective molecule PGE2. Furthermore, FGK administration improved gastric lesion site appearance, clinical symptoms, and mucosal thickness in rats. FGK also reduced gastric fluid volume, free acidity, total acidity, and pepsin activity in the pyloric ligation model. These results suggest that FGK can decrease the inflammatory response and protect the gastric mucosa. FGK therefore has the potential to prevent and treat gastritis and gastric ulcers.

Enterochromaffin-like Cell Hyperplasia-Associated Gastric Neuroendocrine Tumors May Arise in the Setting of Proton Pump Inhibitor Use: The Need for a New Clinicopathologic Category

CONTEXT.—

Hypergastrinemia states such as achlorhydria from gastric mucosal atrophy or a gastrin-producing tumor in humans have been associated with the development of enterochromaffin-like (ECL) cell hyperplasia and gastric neuroendocrine tumors (GNETs). Whether drugs that can elevate serum gastrin levels, such as proton pump inhibitors (PPIs), can produce the same tissue effect is not known and there is no concrete evidence linking the use of PPIs to GNETs outside animal models and case reports.

OBJECTIVE.—

To explore the clinicopathologic association for GNETs of presumed ECL cell origin that cannot be reliably placed into any of the 3 established categories currently recognized by the World Health Organization.

DESIGN.—

This is a retrospective clinicopathologic study of GNETs in the body/fundus of a period of 15 years (2005-2019).

RESULTS.—

Of a total of 87 cases, 57 (65.5%) were associated with atrophic gastritis, 2 (2.3%) were associated with Zollinger-Ellison syndrome, and 28 (32.2%) were unclassified. Of the latter, 11 were consistent with true sporadic/type 3 GNETs, while 17 had background mucosal changes of parietal cell and ECL cell hyperplasia but without underlying detectable gastrinoma, and 88.2% (15 of 17) of patients from this group had documented long-term PPI use. This subtype of GNETs was more commonly multifocal, and of higher grade (P = .03) than "true" sporadic GNETs.

CONCLUSIONS.—

A subset of GNETs arises in the background of gastric mucosal changes suggestive of hypergastrinemia, but without underlying gastrinoma, and could be linked to long-term PPI use.

Towards Understanding of Gastric Cancer Based upon Physiological Role of Gastrin and ECL Cells

Simple Summary

Generally, we know that cancers represent genetic changes in tumour cells, but we most often do not know the causes of cancers or how they develop. Our knowledge of the regulation of gastric acid secretion is well known, with the gastric hormone gastrin maintaining gastric acidity by stimulation of the enterochromaffin-like (ECL) cell to release histamine, which subsequently augments acid secretion. Furthermore, it seems to be a general principle that stimulation of function (which, for the ECL cell, is release of histamine) in a parallel way stimulates the proliferation of the same cell. Long-term hyperstimulation of cell division predisposes to genetic changes and, thus, development of tumours. All conditions with reduced gastric acidity result in an increased risk of gastric tumours due to elevated gastrin in order to restore gastric acidity. It is probable that Helicobacter pylori infection (the most important cause of gastric cancer), as well as drugs inhibiting gastric acid secretion induce gastric cancer in the long-term, due to an elevation of gastrin caused by reduced gastric acidity. Gastric carcinomas have been shown to express ECL cell markers, further strengthening this relationship.

Abstract

The stomach is an ideal organ to study because the gastric juice kills most of the swallowed microbes and, thus, creates rather similar milieu among individuals. Combined with a rather easy access to gastric juice, gastric physiology was among the first areas to be studied. During the last century, a rather complete understanding of the regulation of gastric acidity was obtained, establishing the central role of gastrin and the histamine producing enterochromaffin-like (ECL) cell. Similarly, the close connection between regulation of function and proliferation became evident, and, furthermore, that chronic overstimulation of a cell with the ability to proliferate, results in tumour formation. The ECL cell has long been acknowledged to give rise to neuroendocrine tumours (NETs), but not to play any role in carcinogenesis of gastric adenocarcinomas. However, when examining human gastric adenocarcinomas with the best methods presently available (immunohistochemistry with increased sensitivity and in-situ hybridization), it became clear that many of these cancers expressed neuroendocrine markers, suggesting that some of these tumours were of neuroendocrine, and more specifically, ECL cell origin. Thus, the ECL cell and its main regulator, gastrin, are central in human gastric carcinogenesis, which make new possibilities in prevention, prophylaxis, and treatment of this cancer.

Gastric neuroendocrine tumours from long-term proton pump inhibitor users are indolent tumours with good prognosis

AIMS

Proton pump inhibitors (PPIs) are among the most widely used medications in the United States. Most PPI users have persistent hypergastrinaemia during treatment. However, gastric neuroendocrine tumours diagnosed in long-term PPI users are rarely reported. Their clinicopathological features and prognosis are not characterised. It remains unclear whether or not they can be classified as Type III sporadic tumours.

METHODS AND RESULTS

We retrospectively characterised 66 gastric neuroendocrine tumours from patients without atrophic gastritis and gastrinoma from two tertiary care medical centres, including 38 tumours in patients who had used PPIs for at least 1 year and 28 tumours from patients without long-term PPI use (control group, Type III tumours). Compared to controls, tumours from long-term PPI users tended to be in the pT1-2 category (98% versus 79%, P = 0.09) and less often invaded the serosa (3% versus 18%, P = 0.08) or lymphovascular spaces (11% versus 32%, P = 0.06). Using Kaplan-Meier analysis, long-term PPI users had significantly longer overall survival than controls (P = 0.035). While three control patients developed distant metastasis and seven died, long-term PPI users were without distant metastasis (P = 0.06) or death (P = 0.002) during follow-up. However, five long-term PPI users developed additional gastric neuroendocrine tumour(s), while none of the controls did (P = 0.07).

CONCLUSIONS

Our results show that gastric neuroendocrine tumours of long-term PPI users are probably less aggressive compared to Type III sporadic tumours and have an indolent disease course. Our findings support the classification of gastric neuroendocrine tumours in long-term PPI users as a separate subtype.

Proton Pump Inhibitor Use, Hypergastrinemia, and Gastric Carcinoids-What Is the Relationship?

Neuroendocrine tumors (NETs) throughout the body are the focus of much current interest. Most occur in the gastrointestinal tract and have shown a major increase in incidence over the past 30 years, roughly paralleling the world-wide increase in the use of proton pump inhibitor (PPI) drugs. The greatest rise has occurred in gastric carcinoids (g-NETs) arising from enterochromaffin-like (ECL) cells. These tumors are long known to occur in auto-immune chronic atrophic gastritis (CAG) and Zollinger-Ellison syndrome (ZES), with or without multiple endocrine neoplasia type-1 (MEN-1), but the incidences of these conditions do not appear to have increased over the same time period. Common to these disease states is persistent hypergastrinemia, generally accepted as causing g-NETs in CAG and ZES, and postulated as having similar tumorigenic effects in PPI users. In efforts to study the increase in their occurrence, g-NETs have been classified in a number of discussed ways into different grades that differ in their incidence and apparent pathogenesis. Based on a large amount of experimental data, tumorigenesis is mediated by gastrin’s effects on the CCK2R-receptor on ECL-cells that in turn leads to hyperplasia, dysplasia, and finally neoplasia. However, in all three conditions, the extent of response of ECL-cells to gastrin is modified by a number of genetic influences and other underlying risk factors, and by the duration of exposure to the hormonal influence. Data relating to trophic effects of hypergastrinemia due to PPI use in humans are reviewed and, in an attached Appendix A, all 11 reports of g-NETs that occurred in long-term PPI users in the absence of CAG or ZES are summarized. Mention of additional suspected cases reported elsewhere are also listed. Furthermore, the risk in humans may be affected by the presence of underlying conditions or genetic factors, including their PPI-metabolizer phenotype, with slow metabolizers likely at increased risk. Other problems in estimating the true incidence of g-NETs are discussed, relating to non-reporting of small tumors and failure of the Surveillance, Epidemiology, and End Results Program (SEER) and other databases, to capture small tumors or those not accorded a T1 rating. Overall, it appears likely that the true incidence of g-NETs may be seriously underestimated: the possibility that hypergastrinemia also affects tumorigenesis in additional gastrointestinal sites or in tumors in other organ systems is briefly examined. Overall, the risk of developing a g-NET appears greatest in patients who are more than 10 years on drug and on higher doses: those affected by chronic H. pylori gastritis and/or consequent gastric atrophy may also be at increased risk. While the overall risk of g-NETs induced by PPI therapy is undoubtedly low, it is real: this necessitates caution in using PPI therapy for long periods of time, particularly when initiated in young subjects.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Does the Novel Potassium-Competitive Acid Blocker Vonoprazan Cause More Hypergastrinemia than Conventional Proton Pump Inhibitors? A Multicenter Prospective Cross-Sectional Study

BACKGROUND/AIM

The long-term administration of proton pump inhibitors (PPIs) is useful for preventing recurrent reflux esophagitis. On the other hand, several adverse reactions, such as an increase in the blood gastrin level, have been reported. The aim of the present study was to examine the increase in the blood gastrin level due to the long-term administration of conventional PPIs compared with vonoprazan.

METHODS

A prospective cross-sectional study was conducted. We examined the blood gastrin levels of patients taking vonoprazan or conventional PPIs in whom the grade of atrophic gastritis had been endoscopically evaluated in the last year.

RESULTS

The blood gastrin level was significantly higher in the vonoprazan group than that in the PPI group in patients with milder or no atrophic gastritis, irrespective of the administration periods. However, no significant difference was observed between the groups in patients with severe atrophic gastritis.

CONCLUSION

Vonoprazan more markedly increased the blood gastrin level compared with conventional PPIs in patients with milder or no atrophic gastritis. This indicates that vonoprazan may have stronger acid-suppressing effects in such patients than conventional PPIs. Key Message: We should be aware of the potential development of hypergastrinemia during the long-term administration of vonoprazan, especially in patients with mild or no atrophic gastritis.

Treatment of PPI-resistant gastro-oesophageal reflux: A systematic review

BACKGROUND AND STUDY AIMS

Several studies have demonstrated the superiority of proton-pump inhibitors (PPIs) in resolving erosive gastro-oesophageal reflux disease (GORD). However, this first line of treatment can fail to control symptoms in around 30% of cases, especially in the presence of non-erosive GORD. In situations where the first line of treatment fails, there is a lack of concordance regarding the best strategy to apply. This study presents a systematic review of the trials which have tested second-line treatments after PPI failure.

METHODS

The study was conducted according to the PRISMA statement. The systematic review included medical trials written in English which were published between 2000 and 2016 and were retrieved from PubMed and Scopus using the keywords 'PPI-resistant gastro-oesophageal reflux', 'alginate AND gastro-oesophageal reflux', 'hyaluronic acid AND gastro-oesophageal reflux', 'prokinetics AND gastro-oesophageal reflux', 'sucralfate AND gastro-oesophageal reflux' and 'baclofen AND gastro-oesophageal reflux'.

RESULTS

Ten randomised and non-randomised studies were included, which included 1515 patients of both sexes (mean age = 49.19 years, age range = 18-85, males = 700; 46.2%).

CONCLUSIONS

A personalised choice of the best treatment for PPI-resistant GORD should be based on the results of an upper endoscopy and pH/MII monitoring. For patients in situations where the first line of treatment fails, we encourage the execution of trials for testing double doses of PPIs against alternative medicaments.

Advantages and Disadvantages of Long-term Proton Pump Inhibitor Use

Proton pump inhibitors (PPIs) potently inhibit gastric acid secretion and are widely used for treatment of acid-related diseases including gastroesophageal reflux disease and secondary prevention of aspirin/NSAID-induced ulcers. Although clinically important adverse effects of PPIs can occur, just as with other drugs, those are not frequently observed during or after administration. Thus, PPIs are regarded as relatively safe and considered to be clinically beneficial. Recently, PPIs have become frequently administered to patients with functional gastrointestinal diseases or primary prevention of drug-related gastroduodenal damage, even though their beneficial effects for those conditions have not been fully confirmed. PPIs tend to be given for conditions in which the necessity of the drug has not been clarified, thus otherwise rare adverse effects are presented as clinically relevant. Although several PPI-related adverse effects have been reported, their clinical relevance is not yet clear, since the evidence reported in those studies is not at a high enough level, as the majority are based on retrospective observational studies and the reported hazard ratios are low. It is important to administer PPIs only for patients who will gain a substantial clinical benefit and to continue to investigate their adverse effects with high quality prospective studies.

Factors related to gastric neuroendocrine tumors

INTRODUCTION AND AIMS

An association between long-term use of proton pump inhibitors and the development of gastric neuroendocrine tumors has been reported, but it is still a subject of debate. The aims of the present study were to determine the presence of this association in a Mexican population and to identify the risk factors for developing gastric neuroendocrine tumors.

MATERIALS AND METHODS

A case-control study was conducted, in which the cases were patients with a histopathologic diagnosis of gastric neuroendocrine tumor and the controls were patients evaluated through upper endoscopy. The controls were paired by age, sex, and endoscopic examination indication. Proton pump inhibitor use was considered prolonged when consumption was longer than 5 years.

RESULTS

Thirty-three patients with gastric neuroendocrine tumor and 66 controls were included in the study. Eighteen (54.5%) patients in the case group were women, as were 39 (59%) of the patients in the control group. The median age of the patients in the case group was 55 years (minimum-maximum range: 24-82) and it was 54 years (minimum-maximum range:18-85) in the control group. A greater number of patients in the gastric neuroendocrine tumor group presented with gastric atrophy (p<0.0001) and autoimmune atrophic gastritis (p=0.0002), compared with the control group. No association between gastric neuroendocrine tumor and prolonged proton pump inhibitor use, sex, smoking, gastroesophageal reflux disease, Helicobacter pylori infection, diabetes mellitus, or autoimmune diseases was found in the univariate analysis.

CONCLUSIONS

The results of our study showed no association between proton pump inhibitor use for more than 5 years and the development of gastric neuroendocrine tumor. The presence of gastric atrophy and autoimmune atrophic gastritis was associated with gastric neuroendocrine tumor development.

The Benefits of Combination Therapy with Esomeprazole and Rebamipide in Symptom Improvement in Reflux Esophagitis: An International Multicenter Study

Background/Aims

To investigate the effects of esomeprazole and rebamipide combination therapy on symptomatic improvement in patients with reflux esophagitis.

Methods

A total of 501 patients with reflux esophagitis were randomized into one of the following two treatment regimens: 40 mg esomeprazole plus 300 mg rebamipide daily (combination therapy group) or 40 mg esomeprazole daily (monotherapy group). We used a symptom questionnaire that evaluated heartburn, acid regurgitation, and four upper gastrointestinal symptoms. The primary efficacy end point was the mean decrease in the total symptom score.

Results

The mean decreases in the total symptom score at 4 weeks were estimated to be -18.1±13.8 in the combination therapy group and -15.1±11.9 in the monotherapy group (p=0.011). Changes in reflux symptoms from baseline after 4 weeks of treatment were -8.4±6.6 in the combination therapy group and -6.8±5.9 in the monotherapy group (p=0.009).

Conclusions

Over a 4-week treatment course, esomeprazole and rebamipide combination therapy was more effective in decreasing the symptoms of reflux esophagitis than esomeprazole monotherapy.

Evidence-based clinical practice guidelines for gastroesophageal reflux disease 2015

As an increase in gastroesophageal reflux disease (GERD) has been reported in Japan, and public interest in GERD has been increasing, the Japanese Society of Gastroenterology published the Evidence-based Clinical Practice Guidelines for GERD (1st edition) in 2009. Six years have passed since its publication, and there have been a large number of reports in Japan concerning the epidemiology, pathophysiology, treatment, and Barrett's esophagus during this period. By incorporating the contents of these reports, the guidelines were completely revised, and a new edition was published in October 2015. The revised edition consists of eight items: epidemiology, pathophysiology, diagnosis, internal treatment, surgical treatment, esophagitis after surgery of the upper gastrointestinal tract, extraesophageal symptoms, and Barrett's esophagus. This paper summarizes these guidelines, particularly the parts related to the treatment for GERD. In the present revision, aggressive proton pump inhibitor (PPI) maintenance therapy is recommended for severe erosive GERD, and on-demand therapy or continuous maintenance therapy is recommended for mild erosive GERD or PPI-responsive non-erosive GERD. Moreover, PPI-resistant GERD (insufficient symptomatic improvement and/or esophageal mucosal break persisting despite the administration of PPI at a standard dose for 8 weeks) is defined, and a standard-dose PPI twice a day, change in PPI, change in the PPI timing of dosing, addition of a prokinetic drug, addition of rikkunshito (traditional Japanese herbal medicine), and addition of histamine H2-receptor antagonist are recommended for its treatment. If no improvement is observed even after these treatments, pathophysiological evaluation with esophageal impedance-pH monitoring or esophageal manometry at an expert facility for diseases of the esophagus is recommended.

Are proton pump inhibitors really so dangerous?

For decades, millions of patients with acid-related disorders have had their acid inhibited effectively and safely first with H2-receptor antagonists (H2RAs) and then with proton pump inhibitors (PPI). As with any pharmacological agent, PPIs have been reported to be associated with some adverse events, but several recent large-scale observational studies have evidenced new and serious abnormalities generally linked to their chronic use. However, these studies have often important limitations for their frequent retrospective design and other methodological drawbacks, such as selection biases of the analyzed populations and the presence of various confounding factors. Overall, although the conclusions of these pharmacovigilant investigations must be taken into account and can generate important hypotheses for future research, they do not have to create panic among patients and alarmism among physicians. On considering the weakness of these studies, we suggest physicians should not refrain from continuing to use PPIs, if these drugs are given for medical indications clearly established in the literature and, more importantly, they should not be induced to shift to H2RAs, a class of antisecretory agents that are much less effective than PPIs. A return to the past is potentially dangerous for the patients, taking into account the well-known success of PPIs in the wide spectrum of all acid-related conditions.

Does long-term profound inhibition of gastric acid secretion increase the risk of ECL cell-derived tumors in man?

OBJECTIVE

Since the description of ECL cell-derived tumors in rodents after long-term profound acid inhibition inducing hypergastrinemia, there has been concern that proton pump inhibitors (PPIs) could also do that in man. The recent description of a Spanish family with gastric ECL cell tumors at the age of about 30 years secondary to a defect in the proton pump due to mutation in the ATP4A gene clearly shows that hypergastrinemia alone also is sufficient to induce ECL cell neoplasia in man. The present review aims to evaluate the risk of gastric neoplasia secondary to gastric acid inhibition.

METHODS

Literature (MEDLINE) was searched for the role of the ECL cell in gastric carcinogenesis in animals and man in general and particularly secondary to long-term inhibition of acid secretion.

RESULTS

An important proportion of patients treated with PPI develops hypergastrinemia causing ECL cell hyperplasia and the first descriptions of ECL cell carcinoids secondary to PPI have been reported. The role of the ECL cell has hitherto been under estimated in gastric carcinogenesis in man where for instance the signet ring cell type of gastric carcinoma seems to originate from the ECL cell.

CONCLUSIONS

The first two of three steps in rodent ECL cell carcinogenesis (hyperplasia, carcinoid, and carcinoma) secondary to PPI dosing, have been described for man. It is every reason to believe that the final step, gastric carcinoma, will develop also in man. Clinical decisions should be based not only on so-called evidence based medicine, but also on physiological knowledge and animal studies.

Gastric neuroendocrine neoplasms and proton pump inhibitors: fact or coincidence?

OBJECTIVE

Reporting on three cases of gastric neuroendocrine tumors (g-NETs) in patients taking long-term proton pump inhibitors (PPIs). These tumors are not classifiable considering current criteria. g-NETs are currently grouped as: types 1 and 2, related to hypergastrinemia due to chronic atrophic gastritis and Zollinger-Ellison syndrome respectively, and type 3, normogastrinemic and more aggressive. Although the g-NETs onset in patients taking PPIs is biologically plausible, only a few cases have been reported so far.

MATERIALS AND METHODS

From January 2005 to July 2014, 31 g-NETs were referred to our Unit: 24 (77%), one (3%) and three (10%) resulted types 1, 2 and 3, respectively. Three cases (10%) did not meet the current classification criteria.

RESULTS

The three patients were administered long-term PPIs for gastro-esophageal reflux disease. Patient 1: a 78-year-old man, with a 4-mm well-differentiated g-NET (Ki-67<1%) and marked hypergastrinemia. Patient 2: a 58-year-old man affected by a 6-mm well-differentiated (Ki-67 = 4%) g-NET, with normal gastrin levels. Patients 3: a 67-year-old woman with an 18-mm well-differentiated g-NET (Ki-67 <2%), with mild hypergastrinemia. In the three patients, histology and pertinent blood tests excluded chronic atrophic gastritis, Helicobacter pylori infection or Zollinger-Ellison syndrome. The first two patients underwent endoscopic polypectomy; in the third case total gastrectomy was performed. Further clinical, endoscopic and imaging follow-up did not show any g-NET recurrence.

CONCLUSIONS

The present data point to the existence and epidemiological relevance of g-NETs associated with PPIs intake. These neoplasms are not included in the current classification, thus their treatment and follow-up have not been established.

Potent acid inhibition by vonoprazan in comparison with esomeprazole, with reference to CYP2C19 genotype

BACKGROUND

Acid inhibitory effects of proton pump inhibitors (PPIs) are influenced by CYP2C19 genotype. In contrast, the potent acid inhibition of vonoprazan is not influenced by CYP2C19 genotype.

AIM

To compare the acid inhibitory effects of vonoprazan and esomeprazole in relation to CYP2C19 genotype.

METHODS

Twenty-eight healthy Japanese volunteers [7 CYP2C19 poor metabolisers (PMs), 11 intermediate metabolisers (IMs) and 10 rapid metabolisers (RMs)] received four different regimens in a randomised crossover manner: (i) vonoprazan 20 mg twice daily (b.d.), (ii) vonoprazan 20 mg daily, (iii) esomeprazole 20 mg b.d. and (iv) esomeprazole 20 mg daily. The timing of each dosing was 1 h before a meal. Twenty-four-hour intragastric pH monitoring was performed on day 7 on each regimen.

RESULTS

In the overall genotype group, pH ≥4 holding time ratios (pH 4 HTRs) with vonoprazan b.d., vonoprazan daily, esomeprazole b.d. and esomeprazole daily were 100%, 95%, 91%, and 68% respectively. pH 5 HTRs were 99%, 91%, 84% and 54% respectively. Vonoprazan b.d. potently suppressed acid for 24 h, and was significantly superior to other regimens irrespective of CYP2C19 genotype. Vonoprazan daily was equivalent to esomeprazole b.d. in IMs and PMs, but superior in RMs. CYP2C19 genotype-dependent differences were observed in esomeprazole daily but not in vonoprazan b.d. or daily.

CONCLUSION

Vonoprazan 20 mg b.d. inhibits acid irrespective of CYP2C19 genotype, more potently than esomeprazole 20 mg b.d., pH 4 and 5 holding time ratios reached 100% and 99%, respectively.

Safety of proton pump inhibitors and risk of gastric cancers: review of literature and pathophysiological mechanisms

INTRODUCTION

Despite being an overall safe drug, several long-term adverse effects are associated with proton pump inhibitors (PPIs). The link between PPI use and gastric neuroendocrine tumors (NETs), gastric adenocarcinomas and Barrett's esophagus progression gastric cancers has been investigated due to PPI-induced hypergastrinemia.

AREAS COVERED

The pathophysiological mechanisms underlying PPI exposure and gastric NETs, gastric adenocarcinomas and Barrett's esophagus progression are discussed. The quality of randomized control studies, cohort studies and case reports investigating the link between gastric cancers and PPIs are examined. Recommendations for clinicians are provided.

EXPERT OPINION

PPIs cause a hypergastrinemic state, increasing enterochromaffin-like cell dysplasia and risk of gastric NET development, increasing gastritis severity in the context of Helicobacter pylori infection, and progression of carcinogenesis in a certain predisposed subset of Barrett's esophagus patients. There are case reports of PPI-induced gastric NETs and adenocarcinomas as consequences of these effects. In pernicious anemia and chronic gastritis, clinicians should be aware of potential increased risk of gastric NET development with chronic PPI use in these patients. Eradication status of H. pylori prior to commencing long-term PPI therapy should be established to reduce the risk of severe atrophic gastritis and development of gastric dysplasia.

Systematic review: the effects of long-term proton pump inhibitor use on serum gastrin levels and gastric histology

BACKGROUND

Proton pump inhibitors (PPIs) have a well-established safety profile. However, concerns have been raised about a potential relationship between PPI-induced hypergastrinaemia and the development of enterochromaffin-like (ECL) cell hyperplasia, neuroendocrine tumours and gastric cancer during long-term therapy.

AIM

To review the effects of long-term PPI use on serum gastrin levels and gastric histopathology.

METHODS

A systematic literature search was conducted in PubMed on 21 April 2015 to identify studies reporting the effects of long-term (defined as >3 years) PPI use on gastrin levels and gastric histopathology.

RESULTS

A total of 16 studies (1920 patients) met the inclusion criteria. During long-term PPI therapy, mean gastrin levels rose to one to three times the upper limit of the normal range (~100 pg/mL), and an increased prevalence of ECL cell hyperplasia was observed (+7.8-52.0%). Helicobacter pylori-positive patients had a significantly increased risk of developing ECL linear/micronodular hyperplasia compared with H. pylori-negative patients [OR: 2.45 (95% CI: 1.47-4.10), P = 0.0006]; however, no evidence of neoplastic changes was found. The risk of corpus atrophy was markedly higher in H. pylori-positive patients than in H. pylori-negative patients [OR: 11.45 (95% CI: 6.25-20.99), P < 0.00001]. Not a single case of gastric adenocarcinoma was found.

CONCLUSIONS

Long-term PPI therapy induced moderate hypergastrinaemia in most patients and an increased prevalence of ECL cell hyperplasia. H. pylori-positive patients receiving long-term PPI therapy were exposed to a higher risk of corpus atrophy than H. pylori-negative patients. No neuroendocrine tumours or gastric cancers were found.

Inhibition of lysosomal enzyme activities by proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) are pro-drugs requiring an acidic pH for activation. The specificity of PPI toward the proton pump is mainly due to the extremely low pH at the parietal cell canalicular membrane where the pump is located. Reactivity of PPIs was also observed in moderately acidic environments like the renal collecting duct. But no PPI effect on lysosomal enzymes has been observed possibly because the previous studies were performed with liver tissue, where PPIs are metabolized.

METHODS

The reactivity of PPIs (omeprazole, lansoprazole and pantoprazole) with a cysteine-containing peptide was analyzed by mass spectrometry, and the impact of PPIs on lysosomal enzymes was evaluated in cultured cells and mice. The effect of PPIs on the immune system was examined with a mouse tumor immunotherapy model.

RESULTS

Incubation of a cysteine-containing peptide with PPIs at pH5 led to the conversion of most of the peptide into PPI-peptide adducts. Dose dependent inhibition of lysosomal enzyme activities by PPIs was observed in cultured cells and mouse spleen. Further, PPI counteracted the tumor immunotherapy in a mouse model.

CONCLUSIONS

Our data support the hypothesis that many of the PPI adverse effects are caused by systematically compromised immunity, a result of PPI inhibition of the lysosomal enzymes. This novel mechanism complements the existing mechanisms in explaining the increased incidence of tumorigenesis and infectious diseases among PPI users and underlie the ongoing concern about the overuse of PPIs in adult and pediatric populations.

Gastric carcinoids after long-term use of a proton pump inhibitor

BACKGROUND

Proton pump inhibitors (PPIs) are potent inhibitors of gastric acid secretion and give hypergastrinemia secondary to gastric hypoacidity. PPI treatment therefore induces enterochromaffin-like (ECL) cell hyperplasia. Long-term hypergastrinemia in rodents and man also leads to ECL cell neoplasia. Whether long-term PPI treatment will induce ECL cell neoplasia in man has been disputed.

AIM

To describe gastric carcinoids in two patients with a history of long-term PPI use.

RESULTS

Two patients had been taking PPI for 12-13 years due to gastro-oesophageal reflux disease. At routine upper gastrointestinal endoscopy a solitary tumour was found in the oxyntic mucosa of both patients. Histology from the tumours showed in both cases a well-differentiated neuroendocrine tumour. Biopsies from flat oxyntic mucosa showed no signs of atrophic gastritis and a normal presence of parietal cells in both cases, but hyperplasia of ECL cells. The tumour in patient 1 was resected endoscopically. After cessation of PPI treatment the tumour regressed in patient 2 and the ECL cell hyperplasia regressed in both patients. In patient 2 serum gastrin and chromogranin A were elevated during PPI treatment, and normalised after cessation of treatment. In patient 1, unfortunately, we had serum only after treatment, and at that time both parameters were normal.

CONCLUSION

These cases show that hypergastrinemia secondary to proton pump inhibitors treatment, like other causes of hypergastrinemia, may induce enterochromaffin-like cell carcinoids in man.

Gastric neuroendocrine carcinoma after long-term use of proton pump inhibitor

We present a case of a gastric neuroendocrine carcinoma in a patient with a history of long-term proton pump inhibitor (PPI) use. A 49-year-old man using PPI for the last 15 years due to gastroesophageal reflux disease developed progressive dysphagia, dyspepsia and weight loss. Upper gastrointestinal endoscopy, endoscopic ultrasonography and abdominal CT diagnosed a malignant tumor localized to a hiatal hernia. Fasting serum chromogranin A and gastrin concentrations were elevated (32 nmol/l and 159 pmol/l, respectively). Helicobacter pylori PCR analysis of antral biopsies was negative. Biopsies from endoscopically normal oxyntic mucosa showed enterochromaffin-like (ECL) cell hyperplasia. Tumor biopsies revealed a poorly differentiated neuroendocrine carcinoma. Sevier-Munger staining, immunohistochemistry and electron microscopy indicated ECL cell as origin of the tumor cells. Concerns have previously been raised about the safety of long-term PPI use due to a possible increased risk of cancer. This case illustrates a patient with a poorly differentiated neuroendocrine carcinoma with ECL cell characteristics probably induced by hypergastrinemia secondary to long-term PPI use.

Gastric histology in children treated with proton pump inhibitors long term, with emphasis on enterochromaffin cell-like hyperplasia

BACKGROUND

There are longstanding concerns that carcinoid tumours or atrophic gastritis might develop in children receiving proton pump inhibitors (PPIs) long term. In children, this has not been studied using stains sensitive and specific for enterochromaffin-like (ECL) cells.

AIM

To evaluate gastric biopsies for ECL hyperplasia or gastric atrophy, in children treated long-term with PPIs.

METHODS

Synaptophysin and chromogranin immunostaining, biopsies read anonymised, blinded. Endocrine cell numbers graded according to Rindi and Solcia.

RESULTS

Of 130 children with gastro-oesophageal reflux disease (GERD), 65 had sequential gastric biopsies, starting at median 8.2 years (<1 to 17). Of the 65, 83% had GERD-predisposing conditions, mostly neurological impairment or repaired oesophageal atresia. Four hundred and fifty-eight tissue blocks (208 antrum, 250 body) were available from a mean of 5.8 endoscopies (2-14). Of 82 gastric body biopsies in 40 patients with ECL hyperplasia, 67 had grade 1 hyperplasia, 15 grade 2. Of the 40, nine had ECL hyperplasia before PPI use; all nine had received H2-receptor antagonists. Median duration of PPI use was 3.17 years in patients with ECL hyperplasia, 2.20 years in those without (P=0.16). Helicobacter pylori was present in four patients; two had ECL hyperplasia. PPI duration was >3 years in 24 patients. In nine patients who received H2-receptor antagonists, changes were present before PPI use. No patient had atrophic gastritis.

CONCLUSIONS

A high percentage of children (61%) receiving long-term PPI continuously for up to 10.8 years (median 2.84 years) develop minor degrees of ECL hyperplasia. This has no known clinical significance. Children on PPIs for this duration do not appear to develop atrophic gastritis or carcinoid tumours.

Long-term gastric changes in achlorhydric H(+)/K(+)-ATPase beta subunit deficient mice

OBJECTIVE

Hypergastrinemia is known to induce enterochromaffin-like (ECL) cell derived tumors in rodents and man. In this study, we have examined the effect of life-long gastric anacidity and secondary hypergastrinemia in H(+)/K(+)-ATPase beta subunit knockout (KO) mice.

MATERIAL AND METHODS

Female H(+)/K(+)-ATPase beta subunit KO mice and controls were followed up to 20 months before being sacrificed. At termination, intragastric acidity was measured and internal organs were examined for macroscopic and histological changes. Plasma gastrin and serum albumin were measured.

RESULTS

KO mice were anacidic and hypergastrinemic. The oxyntic mucosa was markedly, and with increase in age, hyperplastic with cystic dilatations resembling the changes seen in patients with Menetrier's disease. Serum albumin in KO mice did not differ from controls. KO mice had a marked ECL cell hyperplasia, but only one gastric carcinoma was found.

CONCLUSION

H(+)/K(+)-ATPase beta subunit KO mice develop Menetrier-like changes in the stomach, and may be useful in studying the pathogenesis and treatment of Menetrier's disease. The reason why only one KO mice developed gastric neoplasia whereas the histamine-2 blocker loxtidine has previously been found to regularly induce ECL cell carcinoids in mice is not known.

Medical versus surgical management for gastro-oesophageal reflux disease (GORD) in adults

BACKGROUND

Gastro-oesophageal reflux disease (GORD) is a common condition with up to 20% of patients from Westernised countries experiencing heartburn, reflux or both intermittently. It is unclear whether medical or surgical (laparoscopic fundoplication) management is the most clinically and cost-effective treatment for controlling GORD.

OBJECTIVES

To compare the effects of medical management versus laparoscopic fundoplication surgery on health-related and GORD-specific quality of life (QOL) in adults with GORD.

SEARCH STRATEGY

We searched CENTRAL (Issue 2, 2009), MEDLINE (1966 to May 2009) and EMBASE (1980 to May 2009). We handsearched conference abstracts and reference lists from published trials to identify further trials. We contacted experts in the field for relevant unpublished material.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing medical management with laparoscopic fundoplication surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from articles identified for inclusion and assessed the methodological quality of eligible trials. Primary outcomes were: health-related and GORD-specific QOL, heartburn, regurgitation and dysphagia.

MAIN RESULTS

Four trials were included with a total of 1232 randomised participants. Health-related QOL was reported by four studies although data were combined using fixed-effect models for two studies (Anvari 2006; REFLUX Trial 2008). There were statistically significant improvements in health-related QOL at three months and one year after surgery compared to medical therapy (mean difference (MD) SF36 general health score -5.23, 95% CI -6.83 to -3.62; I(2) = 0%). All four studies reported significant improvements in GORD-specific QOL after surgery compared to medical therapy although data were not combined. There is evidence to suggest that symptoms of heartburn, reflux and bloating are improved after surgery compared to medical therapy, but a small proportion of participants have persistent postoperative dysphagia. Overall rates of postoperative complications were low but surgery is not without risk and postoperative adverse events occurred although they were uncommon. The costs of surgery are considerably higher than the cost of medical management although data are based on the first year of treatment therefore the cost and side effects associated with long-term treatment of chronic GORD need to be considered.

AUTHORS' CONCLUSIONS

There is evidence that laparoscopic fundoplication surgery is more effective than medical management for the treatment of GORD at least in the short to medium term. Surgery does carry some risk and whether the benefits of surgery are sustained in the long term remains uncertain. Treatment decisions for GORD should be based on patient and surgeon preference.

Unusual multiple gastric carcinoids with hypergastrinemia: report of a case

We report the case of a patient demonstrating multiple gastric carcinoids with hypergastrinemia. A 50-year-old Japanese woman was admitted to our hospital for the further examination of multiple carcinoids of the stomach with hypergastrinemia, although she was asymptomatic. However, based on our clinical examination, this case seemed to be neither type I nor II carcinoid. We performed a total gastrectomy with D1 lymph node dissection. A pathological examination showed numerous endocrine micronests, hyperplasia of the parietal cells extending to the foveolar neck region, and numerous dilated oxyntic glands filled with eosinophilic secretions. Many parietal cells exhibited vacuolated cytoplasms and apical snouts. Furthermore, the dilated glands at the base of the mucosa had hyperchromatic nuclei and ciliated surfaces. The postoperative serum gastrin level was soon normalized to 47 pg/ml. This is only the third reported case of multiple gastric carcinoids with hypergastrinemia due to an intrinsic abnormality in the acid secretion of the parietal cells.

Rebamipide contributes to reducing adverse effects of long-term administration of omeprazole in rats

Proton pump inhibitors (PPIs) have become of great importance for the treatment of peptic ulcer disease and gastroesophageal reflux disease. However, these drugs have several adverse effects, including worsening of corpus atrophic gastritis in patients with H. pylori infection, various histological changes including fundic gland-type polyps, inhibition of glycoprotein production, and hypergastrinemia. On the other hand, it has been reported that rebamipide, a gastroprotective drug, has the potential to increase mucous secretion and basically regulate physiological defensive functions aimed to maintain tissue integrity. In this study, we attempted to clarify whether rebamipide improves morphological changes and hypergastrinemia after administration of omeprazole (OPZ) for 1 year in rats. Eight-week-old male Wistar rats were used. Rats were divided into four groups according to diet as follows: 100 mg/kg body weight OPZ group, 100 mg/kg body weight OPZ and 30 mg/kg body weight rebamipide (OPZ + trebanipide group), 30 mg/kg body weight rebamipide, and normal diet (CRF-1). Morphological changes in gastric mucosa in all groups were studied using hematoxylin and eosin staining, periodic acid-Schiff staining, and immunohistochemical staining for alpha-amylase. Serum gastrin level and basal acid secretion were also examined. In the OPZ group, cystic degenerations with amorphous eosinophilic contents, decreased mucous secretion, decreased chief cells, and development of pancreatic acinar cell metaplasia were detected. However, in the OPZ+rebamipide group, these morphological changes were significantly milder than in the OPZ group. Serum gastrin level and basal acid secretion in the OPZ group increased significantly compared to those in the control group. But these factors in the OPZ+rebamipide group were almost normalized (similar to those of control animals). In conclusion, long-term OPZ treatment causes various morphological changes, hypergastrinemia, and basal acid hypersecretion. The present results suggest that rebamipide contributes to reducing these adverse effects caused by long-term OPZ treatment in rats.

Adéquation aux recommandations des prescriptions des inhibiteurs de la pompe à protons dans un service de médecine interne

INTRODUCTION

Proton pump inhibitors (PPIs) are an efficient therapy, being widely used by physicians. In 2004, cost of PPIs' therapy was as high as 748 millions of euros (for The Caisse primaire d'Assurance Maladie) in France. Although validated indications of PPIs are well known, numerous un-necessary prescriptions of PPIs are common. The aim of this prospective study was to evaluate PPIs' prescriptions of patients in a department of internal medicine.

PATIENTS AND METHODS

This is a 12-week assessment of medical charts of patients, receiving PPI therapy in patients in our department of internal medicine. Data were collected by a standardized questionnaire, with regards to: PPIs' nature and regimen, PPIs' indications as well as duration of therapy.

RESULTS

The medical charts of 729 consecutive patients, with a mean age of 67 years, were collected. Two hundred (and) twenty-four patients (30.7%) received PPI therapy; 157 of these patients were given PPI before admission in our department. Omeprazole was used in 71% of patients. Duration of PPI therapy was over one year in 45% of cases. Thirty-five per cent of family physicians' PPI prescription were validated and 23.8% of those of physicians working in the department of internal medicine. The main non-conform PPI's indications, by family physicians and internists were as follows: prevention of hemorrhagic risk of anti-platelet agent (21 vs 16.4%), anticoagulant (17.8 vs 16.4%), steroids (8.3 vs 13.4%) or non-steroid anti-inflammatory therapy without risk factor (1.9 vs 9%). Finally, in patients receiving PPI therapy before admission, this therapy was maintained in 76% of cases.

CONCLUSION

This prospective study confirms the frequent prescription of PPI therapy in a department of internal medicine (31% of patients). It also underscores the importance of PPIs' use by family physicians and physicians working in a department of internal medicine; this series further highlights the difficulties to interrupt this well tolerated therapy. To date, PPI therapy should be prescribed with a cautious consideration of cost and benefit.

A comparison of the cost effectiveness of pharmacotherapy or surgery (laparoscopic fundoplication) in the treatment of GORD

BACKGROUND

Gastro-oesophageal reflux disease (GORD) causes some of the most frequently seen symptoms in both primary and secondary care. An estimated 4-5 patients (age range 18-60 years) per 10,000 (0.045% of the general population) are receiving maintenance proton pump inhibitors (PPIs) for oesophagitis and reflux. The treatment of reflux disease represents significant prescription drug costs to the UK NHS. An alternative to lifelong pharmacotherapy is surgical treatment of reflux using the laparoscopic fundoplication technique to effect a cure. A multicentre study (REFLUX trial) comparing laparoscopic fundoplication with medical management (PPIs) among patients with GORD is currently underway in the UK. This study includes data collection to contribute to a cost-effectiveness analysis.

OBJECTIVE

To generate some preliminary estimates of the cost effectiveness of surgical and medical management of GORD to guide UK NHS decision making before the REFLUX trial reports.

METHODS

A Markov model was developed in Excel. Probabilistic sensitivity analysis was employed to assess the uncertainty associated with the point estimates. Two strategies were compared: long-term medical management or immediate laparoscopic surgery for GORD. Health outcomes were expressed in terms of QALYs with a lifetime time horizon (30 years) for a patient aged 45 years at commencement of treatment. Costs (pound, 2004 values) of drugs and costs associated with surgery were obtained from five of the REFLUX study centres. Costs and outcomes were discounted by 3.5% per anum. Value of information analysis was used to quantify the cost of uncertainty associated with the decision about which therapy to adopt, indicating the maximum value of future research.

RESULTS

Treatment with laparoscopic fundoplication is the most costly strategy but is also associated with more QALYs. The incremental cost per additional QALY for surgery versus medical management was 180 pounds. However, the cost effectiveness of surgery was uncertain, and the probability that it is cost effective at the threshold of 30,000 pounds per QALY was 0.639. Value of information analysis suggests that further research in this area could be potentially worthwhile. Specifically, this research should focus on the health-related quality of life of patients on medical management or post-surgery.

CONCLUSIONS

The results of the model suggest that, on the basis of current evidence, laparoscopic fundoplication represents a cost effective means of treating GORD rather than lifelong medical management.

Antiulcer drugs and gastric cancer

Inhibitors of gastric acid secretion are efficient drugs in the treatment of acid-related diseases. However, by reducing gastric acidity, hypergastrinemia develops. Gastrin regulates its target cell, the enterochromaffin (ECL) cell, both functionally and tropicaly. Long-term hypergastrinemia in whatever species studied, has been shown to induce tumors originating from the ECL cell. In man, at least 10 years of hypergastrinemia, accompanied by high or reduced gastric acidity is necessary to induce ECL cell carcinoids. There are reports indicating development of ECL cell carcinoids after long-term treatment with proton pump inhibitors. Moreover, the ECL cell may give rise to gastric carcinomas of diffuse type, which have increased during the last decades. Furthermore, most of the carcinomas developing in patients with long-lasting hypergastrinemia are of ECL cell origin. Therefore, long-lasting iatrogenic hypergastrinemia induced by potent inhibitors of acid secretion may be expected to increase the occurrence of gastric carcinomas in the future.

New molecular targets for treatment of peptic ulcer disease

Most patients with peptic ulcer disease are currently treated with proton pump inhibitors or histamine H(2) receptor antagonists. The long-term use of these compounds has been associated with two potential problems. Firstly, proton pump inhibitors may induce enterochromaffin-like (ECL) cell hyperplasia. Secondly, ulcers may relapse despite maintenance therapy with histamine H(2) antagonists. This has been the rationale for the development of new antisecretory agents, including antagonists against gastrin and gastrin releasing peptide (GRP), as well as ligands to histamine H(3) receptors. Several potent, high affinity cholecystokinin (CCK)-2 receptor antagonists have recently been identified such as L-365260, YM-022, RP-73870, S-0509, spiroglumide and itriglumide (CR-2945). Current data suggest that they all have antisecretory and anti-ulcer effects. In addition to reducing acid production, CCK-2 receptor antagonists may possibly also accelerate gastric emptying, a combination of functions which could potentially be beneficial in patients with functional dyspepsia. Receptors for bombesin and its mammalian counterpart GRP have been localised in the brain, spinal cord and enteric nerve fibres of the gut as well as on secretory cells and smooth muscle cells of the intestinal tract. Current data clearly indicate that endogenous GRP is involved in the regulation of basal and postprandial acid secretion. However, at this stage it is not clear whether GRP agonists or GRP antagonists can be developed into useful drugs. The peptide has a wide range of biological effects and it is likely that analogues of GRP or antagonists of the peptide affect not only gastric acid secretion but also induce considerable side effects. Histamine plays a central role in the stimulation of acid secretion. After their detection in the brain, H(3) receptors have been identified in a variety of tissues including perivascular nerve terminals, enteric ganglia of the ileum and lung, and ECL cells. Despite many studies, the role of H(3) receptors in the regulation of gastric acid secretion is still unclear. Controversial data have been presented, and study results largely depend on the species and experimental models. It seems unlikely that proton pump inhibitors or H(2) receptor antagonists will be replaced in the near future by new antisecretory agents. The current shortcomings of the new compounds include mainly their reduced clinical effectiveness and pharmacological limitations. However, the development of these new antisecretory compounds provides interesting tools to assess the physiological and pharmacological role of different receptors within the gastrointestinal tract. The use of CCK-2 receptor antagonists in patients with functional dyspepsia and Zollinger-Ellison syndrome should be examined in randomised, controlled trials.

A 50-year analysis of 562 gastric carcinoids: small tumor or larger problem?

OBJECTIVES

Interest in gastric carcinoid tumors has amplified considerably given the biological establishment of their relationship to gastrin and advances in the elucidation of the pathobiology of such lesions. The recognized propensity of acid-suppressing agents such as the proton pump inhibitor class of drugs to increase plasma gastrin levels has been proposed as a causal relationship in the apparent increase in the identification of such lesions although the increased prevalence of endoscopy and the enhanced awareness of pathologists have also been considered as contributory factors. We sought to examine if there has been an increase in gastric carcinoid incidence time correlative with these parameters.

METHODS

Carcinoid tumor cases from the End Results Group (1950-1969) and the Third National Cancer Survey (TNCS) (1969-1971) databases were combined with the most recent release of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry (1973-1999); these three datasets revealed 13715 carcinoid cases, of which 562 were gastric in origin. Age-adjusted analyses as well as population-based gender and race correction ratios were completed in conjunction with United States decennial census data. To allow a finer granularity in incidence trends, the SEER database was divided into early (1973-1991) and late (1991-1999) subsets. RESULTS Since 1950, the percentage of gastric carcinoids among all gastric malignancies has increased from 0.3% to 1.77%. Since 1969, the proportion of gastric carcinoids among all enteric carcinoid lesions has increased from 2.4% to 8.7%. Age-adjusted incidence rates among male, female, black, and white population subsets have all increased since the TNCS time period, with the greatest increase (800%) noted in white females. The male:female ratio has fallen from 0.90 to 0.54. The occurrence of synchronous or metachronous noncarcinoid tumors with gastric carcinoid tumors has decreased by 26% during the course of SEER data collection. The 5-yr survival rate for gastric carcinoids overall has risen from 51% to 63% during the same time period.

CONCLUSIONS

Gastric carcinoids have increased in incidence over the last 50 yr. Differential increases in predominance across gender and race subdivisions may reflect genetic-based propensities (or protection) for gastric carcinoid tumors among certain ethnic populations. Increased endoscopic surveillance and associated sophisticated pathological evaluation of gastric biopsies undoubtedly are responsible for some of the observed increase in the incidence of gastric carcinoid tumors. These data allow no specific role to be assigned to the effects of acid-suppressive medications. Nevertheless the role of such agents cannot be discounted at this time since the time frame of the increased incidence is somewhat comparable to the introduction of these agents as is the known biological effect of gastrin on ECL cell proliferation.

The use of proton pump inhibitors in children: a comprehensive review

Proton pump inhibitors (PPIs) belong to a group of chemically related compounds whose primary function is the inhibition of acid production in the final common metabolic pathway of gastric parietal cells. PPIs are highly selective and effective in their action and have few short- or long-term adverse effects. These pharmacologic features have made the development of PPIs the most significant advancement in the management of acid peptic related disorders in the last two decades. There are numerous published adult studies that describe the pharmacology, efficacy and safety of these anti-secretory agents; however, in the pediatric population, there are very few comparable studies, particularly multicenter studies with significant patient enrollment. In preparing this article, our aim was to perform a comprehensive review of the literature on the clinical pharmacology and use of PPIs in the pediatric population, and to briefly review some recent articles. Relevant literature was identified by performing MEDLINE/Pubmed searches from January 1990 to December 2001. Combinations of the following search terms were use to analyze these databases: proton pump inhibitor, children, pediatrics, gastroesophageal reflux disease (GERD), esophagitis, intestinal metaplasia, Helicobacter pylori, omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, and safety. Abstracts from the 14th annual conference of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) 2001, and the Disease and Digestive Week 2001, were also included in the review. All pediatric studies reviewed were limited to either omeprazole or lansoprazole. The dosage range used for the management of GERD and related disorders with lansoprazole was 0.73-1.66 mg/kg/day (maximum 30 mg/day). The dosage range for GERD management using omeprazole was 0.3-3.5 mg/kg (maximum 80 mg/day). The dosage range for omeprazole used for H. pylori was 0.5-1.5 mg/kg/day, with a maximum dosage of 40 mg/day, and lansoprazole-containing regimens for H. pylori eradication used dosages ranging from 0.6-1.2 mg/kg/day, with a maximum dosage of 30 mg/day. Few severe adverse events were reported with the use of either drug. Eradication rates for H. pylori were 56-87% for lansoprazole-based triple therapy, and 75-94% for omeprazole-based eradication regimens. To date, there are no published controlled trials of sufficient power comparing the efficacy of the five commercially available PPIs in children, for a variety of acid peptic diseases. Studies suggest that PPIs are highly effective for the management of GERD and related disorders, and are a critically needed component of triple therapy to eradicate H. pylori. PPIs have a very good tolerability profile in adults and children, but long-term tolerability studies are needed, particularly in the pediatric population. Multicenter studies are critically needed to evaluate the second-generation PPIs, to compare PPI efficacy to each other, and to assess the importance of developmental and genetic pharmacology of these drugs in children with acid-peptic disease.

Medical or surgical therapy for erosive reflux esophagitis: cost-utility analysis using a Markov model

OBJECTIVE

To compare the cost and utility of healing and maintenance regimens of omeprazole and laparoscopic Nissen fundoplication (LNF) in the framework of the Canadian medical system.

SUMMARY BACKGROUND DATA

Medical therapy with proton pump inhibitors for endoscopically proven reflux esophagitis is a safe and effective treatment option. Of late, the surgical treatment of choice for this disease has become LNF.

METHODS

The authors' base case was a 45-year-old man with erosive reflux esophagitis refractory to H2-blockers. A cost-utility analysis was performed comparing the two strategies. A two-stage Markov model (healing and maintenance phases) was used to estimate costs and utilities with a time horizon of 5 years. Discounted direct costs were estimated from the perspective of a provincial health ministry, and discounted quality-of-life estimates were derived from the medical literature. Sensitivity analyses were performed to test the robustness of the model to the authors' assumptions and to determine thresholds. A Monte Carlo simulation of 10,000 patients was used to estimate variances and 95% interpercentile ranges.

RESULTS

For the 5-year period studied, LNF was less expensive than omeprazole (3519.89 dollars vs. 5464.87 dollars per patient) and became the more cost-effective option at 3.3 years of follow-up. The authors found that 20 mg/day omeprazole would have to cost less than 38.60 dollars per month before medical therapy became cost effective; conversely, the cost of LNF would have to be more than 5,273.70 dollars or the length of stay more than 4.2 days for medical therapy to be cost effective. Estimates of quality-adjusted life-years did not differ significantly between the two treatment options, and the incremental cost for medical therapy was 129,665 dollars per quality-adjusted life-years gained.

CONCLUSIONS

For patients with severe esophagitis, LNF is a cost-effective alternative to long-term maintenance therapy with proton pump inhibitors.

Changes in gastric mucosa and luminal environment during acid-suppressive therapy: a review in depth

Acid-suppressive therapy and subsequent changes in gastric mucosa and luminal environment rank highly amongst the investigated issues in gastroenterology over the past two to three decades. Herewith, we present an overview of these intragastric changes, particularly during long-term administration of acid-suppresive medication and concurrent infection with Helicobacter pylori. Current evidence indicates that: i) Long-term acid suppression facilitates the development of fundic ECL cell hyperplasia, especially in the presence of Helicobacter pylori. No neoplastic changes directly attributable to acid suppression have so far been demonstrated in humans. ii) Acid-suppressive therapy increases the risk of enteric infections. iii) Acid-suppressive therapy does not alter fat and mineral bioavailability, but may decrease the absorption of protein-bound vitamin B12. iv) Acid suppression invariably results in intragastric overgrowth of non-Helicobacter pylori bacterial species. The concurrent infection with Helicobacter pylori may promote this bacterial overgrowth and the intragastric formation of N-nitrosamines. v) Acid-suppressive therapy alters the natural course of Helicobacter pylori gastritis, transforming the antral-predominant pattern into a body-predominant pattern, which in turn may progress to body gland atrophy. The pathophysiology of this phenomenon is currently under investigation. vi) In view of the potential adverse effects of acid suppression in the presence of Helicobacter pylori, the screen-and-treat strategy is advocated for Helicobacter pylori in subjects considered for long-term treatment.

Serum chromogranin A as a screening test for gastric enterochromaffin-like cell hyperplasia during acid-suppressive therapy

BACKGROUND

Serum chromogranin A (CgA), a marker of neuroendocrine neoplasia, increases during profound gastric acid inhibition, possibly reflecting the trophic effect of gastrin on the enterochromaffin-like (ECL) cells.

AIMS

This study investigated the clinical value of serum CgA as a screening test for gastric fundic enterochromaffin-like (ECL) cell hyperplasia during acid-suppressive therapy.

METHOD

A consecutive series of 230 dyspeptic patients referred for upper gastrointestinal endoscopy was investigated in a cross-sectional design. They were 154 patients on continuous medium-term (6 weeks to one year) or long-term (longer than one year) acid inhibition with either proton pump inhibitors (PPIs, n = 117) or histamine2-receptor antagonists (H2RAs, n = 37) for gastro-oesophageal reflux disease, and 76 nontreated subjects, with normal endoscopic findings (control group). Fasting blood samples were analysed for gastrin and CgA. Gastric biopsy specimens (oxyntic mucosa) were examined for histological evaluation of gastritis (Sydney classification) and of ECL cell hyperplasia (Solcia classification).

RESULTS

Serum CgA levels correlated positively with serum gastrin, following a quadratic function (r = 0.78, P < 0.0001). Elevated serum CgA values during long-term acid inhibition correlated with the presence and severity of fundic ECL cell hyperplasia. Multivariate analysis identified hypergastrinaemia (P < 0.0001), duration of acid inhibition (P < 0.0001), H. pylori infection (P = 0.008), ECL cell hyperplasia (P = 0.012), and body gland atrophy (P = 0.043) as independent predictors of elevated serum CgA. In subjects on long-term acid inhibition (n = 123), serum CgA was equally sensitive but more specific than serum gastrin for the detection of ECL cell hyperplasia (sensitivity, 91.3% for both; specificity, 73% vs. 43%, P < 0.0001).

CONCLUSIONS

During long-term gastric acid inhibition, serum CgA levels reflect the presence and severity of fundic ECL cell hyperplasia. Serum CgA is therefore a useful screening test for gastric ECL cell proliferative changes within this context.

Gastric mucosal morphological consequences of acid suppression: a balanced view

In the chapter, an analysis of the literature on the relationship between Helicobacter pylori, the use of proton pump inhibitors and the development of atrophic gastritis is presented, and the difficulties of classifying gastritis and the new possibilities of quantifying chronic inflammation by morphometric analysis are discussed. The issue surrounding the necessity of eradicating H. pylori in H. pylori-positive patients has still not been solved. Most studies have now accepted that proton pump inhibitors indeed accelerate the onset of atrophic gastritis in H. pylori-positive patients, but evidence against such an association was published in one recent (Scandinavian) study; conclusions from this study have, however, been challenged by several groups. Some data are available on the efficacy of H. pylori eradication with regard to the prevention of atrophy. The limited significance of the development of parietal cell protrusions and fundic gland cysts is better understood, but much less is known of the development and long-term consequence of H. pylori-induced autoimmune gastritis. Finally, recent studies in H. pylori-positive patients indicate that treatment with proton pump inhibitors may promote bacterial N-nitrosation formation. These data taken together suggest that the eradication of H. pylori may be based not only on morphological arguments, but also on bacterial alterations in the gastric milieu.

Personal review: alarmism or legitimate concerns about long-term suppression of gastric acid secretion?

This article responds to controversial issues about the long-term use of acid suppression raised in a recent article in this journal by Waldum & Brenna. Although rebound acid secretion occurs following proton pump inhibitor therapy, the clinical significance of this is unclear, but the proposal that this is a major driver of acid-related diseases is considered implausible. The polypoid deformity of the gastric corpus that can occur with long-term proton pump inhibitor therapy is not neoplastic, and therefore has no bearing on other issues raised about proton pump inhibitor therapy and gastric malignancy. Current data in humans suggest that the magnitude of serum gastrin elevation from proton pump inhibitor treatment of up to 10 years, and any theoretical risks from this, have been overstated by Waldum & Brenna. Pernicious anaemia is a model of very doubtful validity for the risks of proton pump inhibitor therapy on several grounds. The proposal that diffuse gastric carcinoma arises from acid suppression-induced stimulation of enterochromaffin-like cells is challenged vigorously, because this is based on an implausible and substantially criticized interpretation of histopathology. It is agreed that it is appropriate to be cautious about the safety of long-term acid suppression, because no data are available for lifelong treatment in humans. Such caution should be tempered by a critical assessment of the benefits of this treatment in relation to any possible risks. The substantial data that now exist from long-term treatment of humans with proton pump inhibitors has not thus far revealed any definite risks. The risk of death from anti-reflux surgery, although small, would seem to far exceed any possible risks associated with long-term proton pump inhibitor use. Available data suggest that denial of the benefits of effective acid suppressant therapy to patients with clear-cut troublesome acid related disorders is an overreaction to concerns about the biological effects of inhibiting acid secretion with proton pump inhibitors.

Personal review: is profound acid inhibition safe?

Inhibitors of gastric acid secretion, particular proton pump inhibitors, are effective drugs in the treatment and prophylaxis of acid-related diseases. Proton pump inhibitors are therefore prescribed widely, often for minor complaints. Gastric acidity kills swallowed microorganisms, and acid secretion must be of biological importance because it is maintained in phylogenesis. Acid secretion is controlled by feedback mechanisms, mainly via gastrin. A decrease in acidity always causes an increase in plasma gastrin. The trophic effect of gastrin leads to hyperplasia and neoplasia of the enterochromaffin-like (ECL) cell. ECL cell derived tumours in man were previously regarded as rare, and also as rather benign. It is now clear that the ECL cell gives rise to a significant proportion of gastric carcinomas. Moreover, ECL cell carcinoids secondary to hypergastrinaemia may develop into highly malignant tumours. Treatment with a proton pump inhibitor is followed by rebound acid hypersecretion and decreased efficiency of H2-blockers, thus such treatment may induce a type of physical dependence. It is therefore reasonable to be cautious and not to treat younger (< 50 years) patients for long periods of time with profound inhibitors of gastric acid secretion. Chromogranin A in the blood is a sensitive marker of the ECL cell mass, and it could be used to survey patients on long-term proton pump inhibitors.

Clinical and histopathological tumour progression in ECL cell carcinoids ("ECLomas")

AIMS

The aims of this study were to illustrate the malignant potential of gastric enterochromaffin-like (ECL) cell carcinoids (ECLomas) associated with hypergastrinemia, and the gradual neoplastic progression of such tumours. In addition, we examined whether the tyramide signal amplification (TSA) technique could visualize immunohistochemical (IHC) neuroendocrine (NE) features in the dedifferentiated neoplastic ECL cells which were not detected by conventional methods.

METHODS

Conventional histopathological and IHC methods for visualizing ECL cells and cell proliferation were used in addition to the TSA technique.

OBSERVATIONS

Our patient was followed for 5 years. During that period, her ECLoma displayed all the signs of classical tumour progression, ultimately with the appearance of metastases in the regional lymph nodes, the liver and the skin. The neoplastic ECL cells became progressively dedifferentiated with an increasing number of Ki-67 immunoreactive (IR) cell nuclei. In addition, there was a substantial decrease in argyrophil and IR NE cells that could be visualized by conventional methods. By applying the TSA technique, however, the number of IR tumour cells increased considerably.

CONCLUSIONS

ECLomas secondary to hypergastrinemia should be closely followed for signs of clinical and histopathological tumour progression. Such ECLomas deserve early, active, radical surgical treatment. The TSA technique is a valuable tool for visualizing the characteristic IHC features in dedifferentiated NE cells.

[Proton pump inhibitors in pediatrics]

For the past ten years or so, proton pump inhibitors (PPI) such as omeprazole, lansoprazole, or pantoprazole, have become the reference treatment for peptic disorders in adults. PPIs have recently begun to be used in pediatrics, and this use is likely to expand. They act on the final step of gastric acid secretion by completely inhibiting the ATPase (proton pump) at the surface of the gastric parietal cells, thus yielding long term inhibition which is not correlated with the plasma concentration of the drug, in contrast to the effects of H2-blocker drugs. Our knowledge of this new class of treatment in pediatrics is still fragmentary, but the reported pharmacokinetic and clinical data indicate that they are suitable for use in children. While the short-term risk of complications appears to be minimal, the tolerance of these drugs in chronic use requires careful monitoring because of the potential consequences of prolonged inhibition of acid secretion.