Proton pump inhibitors and risk of gastrointestinal cancer: A meta‑analysis of cohort studies

Chemoprevention of Gastrointestinal Cancers: An Umbrella Review of Meta-Analyses of Randomized Controlled Trials and Cohort Studies

Several meta-analyses have investigated the association between chemopreventive agents (CPAs) and the risk of gastrointestinal cancers, but syntheses of the quality of evidence in aggregate are lacking. This umbrella review aimed to assess the quality of evidence from meta-analyses of randomized controlled trials (RCTs) and cohort studies that examine inverse associations between CPAs and the risk of gastrointestinal cancers or any premalignant conditions. Summary effect sizes from random-effects models, between-study heterogeneity, 95% prediction interval, small-study effect, excess significance, and credibility ceilings were devised to classify the credibility of evidence from meta-analyses of cohort studies, whereas the GRADE approach was used for meta-analyses of RCTs. From 20,296 publications, 577 full-text articles were evaluated for eligibility, and 69 articles that provided 194 unique meta-analyses were included. Among meta-analyses of RCTs (N = 93), 26 reached statistical significance (p < 0.05). Seven inverse associations were graded as either high quality (celecoxib and colorectal adenomas, (N = 4)) or moderate (aspirin and colorectal adenomas, (N = 2) and H-pylori eradication and gastric cancer (N = 1)). Among meta-analyses of cohort studies (N = 101), 60 reached statistical significance. Four inverse associations were graded as either convincing (antivirals with hepatocellular carcinoma (HCC); N = 1) or highly suggestive (aspirin with HCC (N = 2) and colorectal cancer (N = 1)). This review suggests that the associations with the most consistent empirical evidence were confined to those targeting the well-established risk factors of gastrointestinal cancer progression. Despite the limited established evidence, the inverse associations observed between metformin and colorectal, esophageal, and gastric cancers, as well as between statins and HCC and gastric cancer, merit further research.

Proton pump inhibitors and the risk of gastric cancer: a systematic review, evidence synthesis and life course epidemiology perspective

OBJECTIVES

Since proton pump inhibitors (PPI) have been introduced, many concerns were raised regarding potential gastric carcinogenicity. We aim to summarise and weigh the epidemiological evidence and address possible causality.

DESIGN

Systematic literature review, evidence synthesis and life-course assessment.

DATA SOURCES

PubMed, Web of Science and Cochrane database (from inception up to October 2024), and back- and forward citation tracking (Web of Science).

ELIGIBILITY CRITERIA

Original studies and quantitative evidence syntheses assessing the association between PPIs and gastric cancer in humans, without language restrictions.

DATA EXTRACTION AND SYNTHESIS

Study design, definitions (and participant numbers) of PPI use and gastric cancer, study characteristics (setting, period, follow-up, lag-time), age and sex distribution presented in tables and evidence mapping.

RESULTS

We identified 33 original studies, 21 meta-analyses, three umbrella meta-analyses, one individual patient data meta-analysis and a Markov model (2006-2023). PPIs were consistently associated with an increased gastric cancer risk with 20/21 meta-analyses reporting pooled relative risks between 1.3 and 2.9. Available trials were underpowered. Reverse causation/protopathic bias, residual confounding (by indication) and lag time seem the largest methodological challenges, as well as disentangling the effects of Helicobacter pylori and its' eradication. Insufficient data are available on age and sex-specific risks, with no studies specifically addressing PPIs in young populations. We hypothesise a sensitive-period exposure model, in which PPI use during pregnancy and early life may be particularly damaging regarding long-term cancer risk. An exploration of Swedish cancer incidence data suggests potential cohort effects as overall gastric cancer risk decreased over time (1970-2022). The risk has increased in young (<40 years) men since the early 2000s, ~10 years after the introduction of Helicobacter pylori eradication and PPIs.

CONCLUSION

Although for older individuals with valid indications, the gastric cancer risk related to PPI use may be limited, we do argue for a more rational and evidence-supported use of PPIs in young populations.

Gastric cancer in patients with Helicobacter pylori-negative autoimmune gastritis

Although Helicobacter pylori (H. pylori) is implicated in the development of most cases of gastric cancer with autoimmune gastritis, cases of gastric cancer have been reported in patients testing negative for H. pylori. Here, we aimed to outline the current research status of the factors involved in the development of gastric cancer in H. pylori-negative autoimmune gastritis. Predictive pathological conditions for the development of gastric cancer in H. pylori-negative autoimmune gastritis are postulated to be: (1) Severe atrophy; (2) Hypergastrinemia; (3) Bile reflux; and (4) Low acidity, which are directly related to the pathophysiology of autoimmune gastritis, as well as smoking and family history, which are not related to autoimmune gastritis. In autoimmune gastritis, where there is a possibility of spontaneous disappearance of H. pylori in advanced atrophy, it is difficult to assess H. pylori. Since H. pylori infection begins in the antrum and subsequently progresses to the proximal stomach, it is interpreted as H. pylori-negative autoimmune gastritis if histologically consistent with autoimmune gastritis in the body with spared antrum, and negative for other H. pylori tests. However, it is essential to examine whether the currently prevailing histological interpretation used to evaluate H. pylori infection status is appropriate.

Gastric Cancer Screening in the United States: A Review of Current Evidence, Challenges, and Future Perspectives

Gastric cancer remains a leading cause of cancer-related mortality worldwide. In the United States, gastric cancer incidence and mortality are substantially higher among non-White racial and ethnic groups and new immigrants from high-incidence countries. This is in large part related to the higher prevalence of Helicobacter pylori -associated gastric premalignant changes in these populations. Apart from primary prevention, early detection of gastric cancer is the principal strategy to reduce gastric cancer mortality and improve survival. Extensive evidence in Asian countries has demonstrated the benefits of endoscopic screening in detecting early-stage gastric cancer and reducing gastric cancer-related mortality. By contrast, direct, high-quality US-based data, such as from large clinical trials or observational studies, on important outcomes of gastric cancer screening are still lacking. In this review, we evaluate and summarize the latest global evidence on the epidemiology and predisposing factors of gastric cancer as well as the efficacy, benefits vs. risks, and cost-effectiveness of gastric cancer screening. We further discuss the critical knowledge gaps and challenges in promoting gastric cancer screening in the United States. Dedicated research is urgently needed to enrich the US-based data on gastric cancer primary and secondary prevention to inform clinical practice and reduce gastric cancer-related morbidity and mortality in a cost and resource efficient manner.

Screening in Gastrointestinal Malignancies-Recent Trials and Advancements

Gastrointestinal cancers, especially colorectal cancer, represent a major health care issue. According to the data, the incidence of these cancers exceeds 50/100,000, mainly in high-income countries. Risk factors for the disease include genetic factors (i.e., Lynch syndrome) and lifestyle factors, e.g., overweight and obesity, smoking tobacco products, low-fiber diet, and low physical activity. When diagnosed early, gastrointestinal cancers can, in most cases, be effectively treated. This review focuses on the presentation of research in the area of screening and its results. It provides insights into current trends in research on methods of early cancer detection and improving screening reporting. Differing levels of screening reporting are one of the main challenges faced by researchers in this field. Research on this issue should be conducted in parallel with research on methods of early diagnosis. Finally, the development of diagnostic methods and communication with patients are important elements of public health.

Should we pay more attention to the potential link between Helicobacter pylori and esophageal cancer in Asian countries

The presence of Helicobacter pylori (H. pylori) infection has been indicated to have a protective influence on esophageal cancer (EC) in some studies, but its specific impact on the risk of esophageal squamous cell carcinoma and esophageal adenocarcinoma remains inconclusive. This manuscript comment addresses the recent study by López-Gómez et al. Despite it was a retrospective observational study without a control group, this study revealed a notably low prevalence of H. pylori infection among EC patients, indicating a potential association between H. pylori and EC in Spain. It is important to note that the relationship between H. pylori and the risk of EC varies geographically. We also conducted a meta-analysis focusing on this association in Asian populations to offer precise clinical insights. However, no significant correlation between H. pylori infection and EC was identified, suggesting that the perceived protective effect of H. pylori against EC may have been overestimated in the Asian population.

Anti-ulcerogenic Potential of Kalanchoë gastonis-bonnieri Extracts in Male ICR Mice Model of Ethanol-induced Gastric Ulcers

Peptic ulcers (PU) are a breach in the mucosa of the digestive tract and are related to several factors including an altered immune system and an unbalanced diet. Current treatment carries to long-term complications; therefore, the use of medicinal plants is an alternative for several inflammatory diseases including ulcerative lesions. Kalanchoë gastonis-bonnieri, is a succulent plant and, has been used in traditional medicine against gastric ulcers, inflammation, and cancer among others. The main goal of this work was to analyze the anti-ulcerogenic potential of extracts from leaves of K. gastonis-bonnieri in an assay of ethanol-induced gastric ulcers. An ethanolic extract was obtained by maceration from fresh leaves of K. gastonis-bonnieri, and fractions were obtained through bipartition and chemical fractioning. The chemical characterization of the extract was made through HPLC, GC-MS, and NMR. Total extract and fractions showed an anti-ulcerogenic effect in specimens of male ICR mice with a gastric ulcer index (UI) of 3.27-5.47. The recorded effect is attributed to the presence of terpenoid compounds such as β-Amyrin acetate, which showed antioxidant properties and lessened formations of ulcers induced by ethanol administration in mice stomach.

Helicobacter pylori Eradication Therapy and the Risk of Colorectal Cancer: A Population-Based Nationwide Cohort Study in Sweden

BACKGROUND

Helicobacter pylori (H. pylori) is an established gastric carcinogen, also associated with an increased risk of colorectal cancer. Therefore, we suspected that H. pylori eradication lowers the risk of colorectal cancer.

MATERIAL AND METHODS

We assessed if H. pylori eradication therapy is associated with a reduced risk of colorectal adenocarcinoma in a population-based nationwide cohort study. This study included all Swedish adults with at least one recorded H. pylori eradication episode between July 2005 and December 2012, based on the high-quality Swedish health registries. Colorectal adenocarcinoma risks were compared to the Swedish background population, presented as standardized incidence ratios (SIRs) and 95% confidence intervals (CIs), accounting for age, sex, calendar period, tumor location (left or right sided), stage, and number of eradication episodes, from 1 year after eradication and onward.

RESULTS

Among 80,381 individuals receiving H. pylori eradication therapy (average follow-up 4.1 years), 282 were diagnosed with colorectal cancer (97.2% adenocarcinoma). Overall, H. pylori eradication was associated with an elevated risk of colorectal adenocarcinoma (SIR 1.27, 95% CI: 1.12-1.43). The colorectal adenocarcinoma risk was increased 1-2 years after eradication (SIR 1.42, 95% CI: 1.17-1.72), then decreased 2-4 years (SIR 0.80, 95% CI: 0.65-0.98) and 4-6 years (SIR 0.76, 95% CI: 0.57-0.99), yet not ≥ 6 years (SIR 1.36, 95% CI: 0.78-2.21) after eradication compared to the general population. Overall, right-sided (SIR 1.47, 95% CI: 1.21-1.76) and left-sided (SIR 1.35, 95% CI: 1.09-1.67) colon adenocarcinomas risks were higher among eradicated individuals than the general population.

CONCLUSION

H. pylori eradication was not associated with a clear and consistent reduction of colorectal cancer in our Swedish cohort.

Long-Term Proton Pump Inhibitor-Acid Suppressive Treatment Can Cause Vitamin B12 Deficiency in Zollinger-Ellison Syndrome (ZES) Patients

Whether the long-term treatment of patients with proton pump inhibitors (PPIs) with different diseases [GERD, Zollinger-Ellison syndrome (ZES), etc.] can result in vitamin B12 (VB12) deficiency is controversial. In this study, in 175 patients undergoing long-term ZES treatment with anti-acid therapies, drug-induced control acid secretory rates were correlated with the presence/absence of VB12 deficiency, determined by assessing serum VB12 levels, measurements of VB12 body stores (blood methylmalonic acid (MMA) and total homocysteine[tHYC]), and other features of ZES. After a mean of 10.2 yrs. of any acid treatment (5.6 yrs. with PPIs), 21% had VB12 deficiency with significantly lower serum and body VB12 levels (p < 0.0001). The presence of VB12 deficiency did not correlate with any feature of ZES but was associated with a 12-fold lower acid control rate, a 2-fold higher acid control pH (6.4 vs. 3.7), and acid control secretory rates below those required for the activation of pepsin (pH > 3.5). Over a 5-yr period, the patients with VB12 deficiency had a higher rate of achlorhydria (73% vs. 24%) and a lower rate of normal acid secretion (0% vs. 49%). In conclusion, in ZES patients, chronic long-term PPI treatment results in marked acid hyposecretion, resulting in decreased serum VB12 levels and decreased VB12-body stores, which can result in VB12 deficiency.

Long-Term Intake of Proton-Pump Inhibitors Could Be Associated with an Increased Incidence of Liver Cancer in Women

BACKGROUND

Proton pump inhibitors (PPIs) are among the most commonly prescribed drugs in gastroenterology. Although PPIs are mostly well tolerated, long-term PPI intake has been linked with diabetes mellitus, osteoporosis and infectious disease. In the present study, we evaluated a potential association between PPI intake and a subsequent diagnosis of liver cancer in a large real-world cohort of outpatients in Germany.

METHODS

A total of 1766 patients with liver cancer, as well as 8830 propensity-score-matched controls, were identified from the Disease Analyzer database (IQVIA). The outcome of the study was the association between PPI use and a subsequent diagnosis of liver cancer, which was evaluated using multivariable logistic regression analyses.

RESULTS

Overall, 42.9% of the liver cancer patients and 39.0% of the controls received at least one PPI prescription before the index date. PPI prescriptions at any time before the index date were associated with an increased risk of subsequent liver cancer (OR: 1.18; 95% CI: 1.06-1.31). The positive association was observed in all age groups, as well as in women and men, but only in women (OR: 1.30; 95% 1.09-1.55) did it reach the predefined level of significance (p < 0.01). When considering the duration of PPI therapy, only PPI therapy for at least two years was significantly associated with an increased risk of liver cancer (OR: 1.28; 95% 1.09-1.50). In an analysis stratified by age and sex, this association was strongest in the age group < 60 years (OR: 1.99; 95% 1.21-3.26).

CONCLUSIONS

Our data suggest that long-term PPI intake in women as well as in patients < 60 years might be associated with an increased risk of liver cancer. These findings support current efforts to reduce the inappropriate use of PPIs in routine clinical practice and to link PPI prescribing to a clear medical indication.