Acid-suppressive medications and risk of colorectal cancer: results from three large prospective cohort studies

Proton Pump Inhibitors and Oral-Gut Microbiota: From Mechanism to Clinical Significance

Proton pump inhibitors (PPIs) are some of the most commonly prescribed drugs worldwide, but there are increasing concerns about digestive complications linked to PPIs. Next-generation sequencing studies have suggested that PPIs can significantly affect the composition of the gut microbiota, which in turn may substantially contribute to the development of these complications. Recently, emerging evidence has suggested that the translocation of oral microbes into the gut may be the primary mechanism underlying the alterations in the gut microbiota induced by PPIs in the presence of gastric acid suppression and impaired oral-gut barrier function. Moreover, the significance of oral-gut microbial translocation in health and disease conditions has gained increasing recognition. Consequently, it is imperative to enhance our understanding of the functions of the oral-gut microbiota axis in digestive disorders associated with PPI therapies. This review aims to summarize current research findings and further elucidate the contribution of the oral-gut microbiota to the pathogenesis of PPI-related digestive diseases. We aim to provide a theoretical foundation for future therapeutic and preventive strategies targeting PPI-related digestive complications through modulation of the oral-gut microbiota.

Maintenance proton pump inhibitor use and risk of colorectal cancer: a Swedish retrospective cohort study

OBJECTIVES

We aimed to evaluate the risk of colorectal adenocarcinoma (CRA) associated with long-term use of proton pump inhibitors (PPIs) in a large nationwide cohort.

DESIGN

Retrospective cohort study.

SETTING

This research was conducted at the national level, encompassing the entire population of Sweden.

PARTICIPANTS

This study utilised Swedish national registries to identify all adults who had ≥180 days of cumulative PPI use between July 2005 and December 2012, excluding participants who were followed up for less than 1 year. A total of 754 118 maintenance PPI users were included, with a maximum follow-up of 7.5 years.

INTERVENTIONS

Maintenance PPI use (cumulative≥180 days), with a comparator of maintenance histamine-2 receptor antagonist (H2RA) use.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the risk of CRA, presented as standardised incidence ratios (SIRs) with 95% confidence intervals (CIs). Subgroup analyses were performed to explore the impact of indications, tumour locations, tumour stages and the duration of follow-up. A multivariable Poisson regression model was fitted to estimate the incidence rate ratios (IRRs) and 95% CIs of PPI versus H2RA use.

RESULTS

Maintenance PPI users exhibited a slightly elevated risk of CRA compared to the general population (SIR 1.10, 95% CI=1.06 to 1.13) for both men and women. Individuals aged 18-39 (SIR 2.79, 95% CI=1.62 to 4.47) and 40-49 (SIR 2.02, 95% CI=1.65 to 2.45) had significantly higher risks than the general population. Right-sided CRA showed a higher risk compared to the general population (SIR 1.26, 95% CI=1.20 to 1.32). There was no significant difference in the risk of CRA between maintenance PPI users and maintenance H2RA users (IRR 1.05, 95% CI=0.87 to 1.27, p<0.05).

CONCLUSIONS

Maintenance PPI use may be associated with an increased risk of CRA, but a prolonged observation time is needed.

Proton pump inhibitors stabilize the expression of PD-L1 on cell membrane depending on the phosphorylation of GSK3β

BACKGROUND

Preclinical and clinical evidence indicates that proton pump inhibitors (PPIs) may indirectly diminish the microbiome diversity, thereby reducing the effectiveness of immune checkpoint inhibitors (ICIs). Conversely, recent publications have shown that PPIs could potentially enhance the response to ICIs. The precise mechanism through which PPIs modulate the ICIs remains unclear. In this study, we discovered a novel molecular function of PPIs in regulating immune invasion, specifically through inducing PD-L1 translocation in various tumor cells.

METHODS

C57BL/6 mice subcutaneous transplantation model is used to verify the potential efficacy of PPIs and PD-L1 antibody. Western blotting analysis and phosphorylated chip are used to verify the alteration of PD-L1-related pathways after being treated with PPIs. The related gene expression is performed by qRT-PCR and luciferase reporter analysis. We also collected 60 clinical patients diagnosed with esophageal cancer or reflux esophagitis and then detected the expression of PD-L1 in the tissue samples by immunohistochemistry.

RESULTS

We observed that the IC50 of tumor cells in response to PPIs was significantly higher than that of normal epithelial cells. PPIs significantly increased the expression of PD-L1 on cell membrane at clinically relevant concentrations. Furthermore, pre-treatment with PPIs appeared to synergize the efficiency of anti-PD-L1 antibodies in mouse models. However, PPI administration did not alter the transcription or total protein level of PD-L1 in multiple tumor cells. Using a phosphorylated protein chip, we identified that PPIs enhanced the phosphorylation of GSK3β, then leading to PD-L1 protein translocation to the cell membranes. The capacity of PPIs to upregulate PD-L1 was negated following GSK3β knockout. Furthermore, our clinical data showed that the PPIs use resulted in increased PD-L1 expression in esophageal cancer patients.

CONCLUSION

We mainly address a significant and novel mechanism that the usage of PPIs could directly induce the expression of PD-L1 by inducing GSK3β phosphorylation and facilitate primary tumor progression and metastasis.

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

Although proton pump inhibitors (PPIs) are widely used in the treatment of various acid-related disorders, observational studies have raised concern about an association between PPI use and the risk of gastrointestinal cancer. The present study aimed to investigate the association between them using a meta-analysis of cohort studies. PubMed and Excerpta Medica dataBASE were searched from inception to December 2022 to identify relevant cohort studies. The primary outcome was the risk of gastrointestinal cancer among PPI users, expressed as a pooled odds ratio (OR), relative risk (RR) or hazard ratio (HR) and its 95% CI based on a random-effects model. A total of 25 cohort studies from 23 articles were included in the final analysis. In the meta-analysis of all studies, an increased risk of gastrointestinal cancer following the use of PPIs was observed (OR/RR/HR, 2.09; 95% CI, 1.78-2.46). Subgroup analyses by type of cancer also revealed an association between PPI use and the risk of esophageal, gastric, liver and pancreatic cancer, whereas there was no association for colorectal cancer. The increased risk of gastrointestinal cancer was also observed in individuals who had used PPIs for <1 year (OR/RR/HR, 5.23; 95% CI, 2.96-9.24) as well as individuals who had used PPIs for up to 3 years. The present meta-analysis revealed that the use of PPIs was associated with an increased risk of gastrointestinal cancer.

Proton Pump Inhibitors and Likelihood of Colorectal Cancer in the Korean Population: Insights from a Nested Case-Control Study Using National Health Insurance Data

The potential connection between proton pump inhibitors (PPIs) and colorectal cancer (CRC) risk remains unclear, with specific ethnic genetic backgrounds playing a role in PPI-induced adverse effects. In this nested case-control study, we investigated the risk of CRC in relation to preceding PPI use and the duration of use using data from the Korean National Health Insurance Service-National Sample Cohort database, including 9374 incident CRC patients and 37,496 controls. To assess the impact of preceding PPI exposure (past vs. current) and use duration (days: <30, 30-90, and ≥90) on incident CRC, we conducted propensity score overlap-weighted multivariate logistic regression analyses, adjusted for confounding factors. Our findings revealed that past and current PPI users had an increased likelihood of developing CRC. Regardless of duration, individuals who used PPIs also had higher odds of developing CRC. Subgroup analyses revealed that CRC occurrence increased independent of history or duration of prior PPI use, consistent across various factors such as age, sex, income level, and residential area. These findings suggest that PPI use, regardless of past or present use and duration of use, may be related to an increased risk of developing CRC in the Korean population.

Meta-analysis of proton pump inhibitor use and the risk of developing gastric cancer or colorectal cancer

To evaluate the relationship between the use of proton pump inhibitors (PPI) and the risk of gastric cancer and colorectal cancer by using meta-analysis. Computer search PUBMED, EMBASE, Cochrane Library, CNKI and Wanfang database to obtain relevant literature on the use of PPI and the risk of gastric cancer and colorectal cancer, extract relevant data, and use Stata14.0 for Meta-analysis. A total of 24 articles were included, including 12 articles for gastric cancer and 12 articles for colorectal cancer. A total of 5 313 749 persons were included in the study and analysis. Meta-analysis results showed that the risk of gastric cancer in PPI users was significantly increased [risk ratio (RR) = 2.04, 95% confidence interval (CI) (1.33-2.75)], and the regional subgroup analysis results showed that in Europe [RR = 2.01, 95% CI (0.92, 3.09), P < 0.05] and Asia [RR = 2.15, 95% CI (1.16, 3.14), P < 0.05] This risk is higher, and Asia is higher than Europe. The risk of colorectal cancer is slightly increased [RR = 1. 22, 95% CI (1.03, 1.40, P < 0.05], and the regional subgroup analysis results show that in Europe [RR = 1.05 95% CI (0.98, 1.12), P < 0.05] and Asia [RR = 1.18, 95% CI (1.10, 1.27), P < 0.05]. This risk is low, but Asia is higher than Europe. The use of PPI significantly increases gastric cancer However, the risk of colorectal cancer is not significantly increased. The risk of gastric cancer and colorectal cancer in the population using PPI in Asia is higher than that in Europe.

Adverse Effects Associated with Long-Term Use of Proton Pump Inhibitors

Proton Pump Inhibitors are used widely to manage many gastric acid-related conditions such as gastroesophageal disease, gastritis, esophagitis, Barrett's esophagus, Zollinger-Ellison syndrome, peptic ulcer disease, nonsteroidal anti-inflammatory drug-associated ulcers, and Helicobacter pylori eradication, around the globe. This review article focuses on adverse effects associated with the long-term use of proton pump inhibitors. Various observational studies, clinical trials, and meta-analyses have established the adverse effects associated with the long-term use of proton pump inhibitors including renal disorders (acute interstitial nephritis, acute kidney injury, chronic kidney disease, and end-stage renal disease), cardiovascular risks (major adverse cardiovascular events, myocardial infarction, stent thrombosis, and stroke), fractures, infections (Clostridium difficile infection, community-acquired pneumonia, and Coronavirus disease 2019), micronutrient deficiencies (hypomagnesemia, anemia, vitamin B12 deficiency, hypocalcemia, hypokalemia), hypergastrinemia, cancers (gastric cancer, pancreatic cancer, colorectal cancer, hepatic cancer), hepatic encephalopathy, and dementia. Clinicians including prescribers and pharmacists should be aware of the adverse effects of taking proton pump inhibitors for an extended period of time. In addition, the patients taking proton pump inhibitors for long-term should be monitored for the listed adverse effects. The American Gastroenterological association recommends a few non-pharmacological measures and the use of histamine 2 blockers to lessen gastrointestinal symptoms of gastroesophageal reflex disease and the utilization of proton pump inhibitors treatment if there is a definitive indication. Additionally, the American Gastroenterological association's Best Practice Advice statements emphasize deprescribing when there is no clear indication for proton pump inhibitors therapy.

Association of proton pump inhibitors with gastric and colorectal cancer risk: A systematic review and meta-analysis

Background: Proton pump inhibitors (PPI) are generally considered to be one of the well-established prescription drug classes and are commonly used to treat most acid-related diseases. However, a growing body of literature showing an association between gastric and colorectal cancer risk and PPI use continues to raise concerns about the safety of PPI use. Therefore, we aimed to investigate the association between proton pump inhibitor use and risk of gastric and colorectal cancer.

Methods: We collected relevant articles using PubMed, Embase, Web of Science and Cochrane library from 1 January 1990 to 21 March 2022. The pooled effect sizes were calculated based on the random-effects model. The study was registered with PROSPERO (CRD42022351332).

Results: A total of 24 studies (n = 8,066,349) were included in the final analysis in the screening articles. Compared with non-PPI users, PPI users had a significantly higher risk of gastric cancer (RR = 1.82, 95% CI: 1.46–2.29), but not colorectal cancer (RR = 1.22, 95% CI: 0.95–1.55). Subgroup analysis showed that there was a significant positive correlation between the use of PPI and the risk of non-cardiac cancer (RR = 2.75, 95% CI: 2.09–3.62). There was a significant trend between the duration dependent effect of PPI use and the risk of gastric cancer (&lt;1 year RR = 1.56, 95% CI: 1.30–1.86; 1–3 years RR = 1.75, 95% CI: 1.28–2.37; &gt;3 years RR = 2.32, 95% CI: 1.15–4.66), but not colorectal cancer (≤1 year RR = 1.00, 95% CI: 0.78–1.28; &gt;1 year RR = 1.18, 95% CI: 0.91–1.54; ≥5 years RR = 1.06, 95% CI: 0.95–1.17).

Conclusion: We found that PPI use increased gastric cancer risk, but not colorectal cancer risk. This result may be biased due to confounding factors. More prospective studies are needed to further validate and support our findings.

Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351332], identifier [CRD42022351332].

Association between the Co-administration of Histamine H2 Receptor Antagonists and the Effectiveness of Capecitabine in Patients with Colorectal Cancer: Propensity Score Analysis

Background: The association between the effectiveness of capecitabine and the concomitant administration of gastric acid suppressants remains controversial. We aimed to clarify whether the effectiveness of capecitabine is affected by the co-administration of histamine H₂ receptor antagonists (H₂RAs) in early-stage colorectal cancer (CRC) patients using real-world data. Methods: This multicenter, retrospective, observational study included consecutive patients with stage II-III CRC who received either capecitabine monotherapy or the CapeOX regimen (capecitabine and oxaliplatin) as adjuvant therapy between January 2009 and December 2014 in Japan. Relapse-free survival (RFS) and overall survival were estimated using the Kaplan-Meier method. Additionally, multivariable Cox proportional hazards model, propensity score adjustment, and inverse probability of treatment weighting analyses were performed. Results: In total, 552 patients were included in this study, of which 30 were co-administered H₂RAs. RFS at five years was 76.7% (95% confidence interval [CI]: 57.2-88.1%) and 79.8% (95% CI: 76.0-83.0%) in the H₂RA and non-H₂RA groups, respectively. Multivariable Cox proportional hazards model and propensity score-adjusted analyses showed that the co-administration of H₂RAs was associated with a poor RFS among those receiving capecitabine monotherapy (hazard ratio [HR], 2.01; 95% CI: 0.86-4.70 and HR, 1.81; 95% CI: 0.77-4.22, respectively). In contrast, these results were inconsistent with the group receiving the CapeOX regimen. Conclusions: The study findings suggest that the co-administration of H₂RAs may not reduce the effectiveness of capecitabine therapy in patients with early-stage CRC. To confirm this relationship, a prospective study with a pharmacokinetic approach is needed.

Proton Pump Inhibitor Use and Obesity-Associated Cancer in the Women's Health Initiative

Proton pump inhibitors (PPIs) have off-target activity on fatty acid synthase (FASN), a critical enzyme in energy balance and cancer growth. We evaluated risk of common obesity-related cancers: breast, colorectal (CRC), and endometrial, with use of PPI and histamine-2 receptor antagonists (H2RA) in 124,931 postmenopausal women enrolled in the Women's Health Initiative. Incident cancer cases were physician-adjudicated. Cox proportional hazards models were used to estimate multivariable hazard ratios (HR) and 95% confidence intervals (CI) for cancer incidence after year 3. There were 7956 PPI ever users and 9398 H2RA only users. Ever use of either PPI or H2RA was not associated with risk of breast cancer (n = 9186) nor risk of endometrial cancer (n = 1231). The risk of CRC (n = 2280) was significantly lower in PPI users (HR = 0.75, 95% CI = 0.61-0.92), but not in H2RA users (HR = 1.13, 95% CI = 0.97-1.31). The association of PPI use with CRC was apparent regardless of BMI or NSAID use, and was stronger with longer PPI duration (p = 0.006) and potency (p = 0.005). The findings that PPI use, but not H2RA use, demonstrate an inverse dose-response relationship with risk of CRC is consistent with preclinical data showing FASN inhibition prevents colon cancer progression and supports a role of PPI in CRC prevention.

Proton pump inhibitors and risk of colorectal cancer

OBJECTIVE

To determine whether proton pump inhibitors (PPIs) are associated with an increased risk of colorectal cancer, compared with histamine-2 receptor antagonists (H2RAs).

DESIGN

The United Kingdom Clinical Practice Research Datalink was used to identify initiators of PPIs and H2RA from 1990 to 2018, with follow-up until 2019. Cox proportional hazards models were fit to estimate marginal HRs and 95% CIs of colorectal cancer. The models were weighted using standardised mortality ratio weights using calendar time-specific propensity scores. Prespecified secondary analyses assessed associations with cumulative duration, cumulative dose and time since treatment initiation. The number needed to harm was calculated at five and 10 years of follow-up.

RESULTS

The cohort included 1 293 749 and 292 387 initiators of PPIs and H2RAs, respectively, followed for a median duration of 4.9 years. While the use of PPIs was not associated with an overall increased risk of colorectal cancer (HR: 1.02, 95% CI 0.92 to 1.14), HRs increased with cumulative duration of PPI use (<2 years, HR: 0.93, 95% CI 0.83 to 1.04; 2-4 years, HR: 1.45, 95% CI 1.28 to 1.60; ≥4 years, HR: 1.60, 95% CI 1.42 to 1.80). Similar patterns were observed with cumulative dose and time since treatment initiation. The number needed to harm was 5343 and 792 for five and 10 years of follow-up, respectively.

CONCLUSION

While any use of PPIs was not associated with an increased risk of colorectal cancer compared with H2RAs, prolonged use may be associated with a modest increased risk of this malignancy.

Proton pump inhibitors and colorectal cancer: A systematic review

BACKGROUND

The use of proton pump inhibitors (PPI) is common worldwide, with reports suggesting that they may be overused. Several studies have found that PPI may affect colorectal cancer (CRC) risk.

AIM

To summarize current knowledge on the relationship between PPI and CRC from basic research, epidemiological and clinical studies.

METHODS

This systematic review was based on the patients, interventions, comparisons, outcome models and performed according to PRISMA guidelines. MEDLINE, EMBASE, Scopus, and Web of Science databases were searched from inception until May 17, 2021. The initial search returned 2591 articles, of which, 28 studies met the inclusion criteria for this review. The studies were categorized as basic research studies (n = 12), epidemiological studies (n = 11), and CRC treatment studies (n = 5). The quality of the included studies was assessed using the Newcastle-Ottawa Scale or Cochrane Risk of Bias 2.0 tool depending on the study design.

RESULTS

Data from basic research indicates that PPI do not stimulate CRC development via the trophic effect of gastrin but instead may paradoxically inhibit it. These studies also suggest that PPI may have properties beneficial for CRC treatment. PPI appear to have anti-tumor properties (omeprazole, pantoprazole), and are potential T lymphokine-activated killer cell-originated protein kinase inhibitors (pantoprazole, ilaprazole), and chemosensitizing agents (pantoprazole). However, these mechanisms have not been confirmed in human trials. Current epidemiological studies suggest that there is no causal association between PPI use and increased CRC risk. Treatment studies show that concomitant PPI and capecitabine use may reduce the efficacy of chemotherapy resulting in poorer oncological outcomes, while also suggesting that pantoprazole may have a chemosensitizing effect with the fluorouracil, leucovorin, oxaliplatin (FOLFOX) regimen.

CONCLUSION

An unexpected inhibitory effect of PPI on CRC carcinogenesis by way of several potential mechanisms is noted. This review identifies that different PPI agents may have differential effects on CRC treatment, with practical implications. Prospective studies are warranted to delineate this relationship and assess the role of individual PPI agents.

Comprehensive analysis of proton pump inhibitors and risk of digestive tract cancers

BACKGROUND

For the past two decades, dispute on whether proton pump inhibitor (PPI) leads to digestive tract cancer remains, and emerging studies in recent years still demonstrate inconsistent results, which continues to perpetuate concerns over the safety of PPI use. We performed a systematic review and meta-analysis, with comprehensive evaluation by Bradford Hill criteria of causation, to assess the effect of PPI use on digestive tract cancers.

METHODS

Medline, Embase and Web of Science databases were searched for observational studies published up to 15th January 2021. Pooled relative risks (RRs) were estimated via random effects models. Cumulative defined daily dose- and duration-risk relationships using restricted cubic spline and fractional polynomial models were investigated. Bradford Hill criteria were applied to evaluate causation. PROSPERO Registration: CRD42020211103.

RESULTS

Thirty-two publications containing 4,355,254 participants were included. PPI use is associated with an increased risk of overall digestive tract cancers (RR = 1.63, 95% confidence interval (CI) 1.33 to 2.00). PPI use is correlated with increased risks of gastric cancer (RR = 1.78, 95% CI 1.38 to 2.31), pancreatic cancer (RR = 1.72, 95% CI 1.05 to 2.82) and liver cancer (RR = 1.62, 95% CI 1.04 to 2.52), but not of esophageal cancer (RR = 2.06, 95% CI 0.65 to 6.57) and colorectal cancer (RR = 1.24, 95% CI 0.93 to 1.66). The association between PPI and digestive tract cancers is stronger in people with minimal exposure. When cumulative defined daily dose or duration increases, the risks decline and become non-significant. Evaluation by Bradford Hill criteria indicates weak evidence of causation.

CONCLUSIONS

A causal relationship between PPI use and digestive tract cancers is not supported by the evidence in the current review. Concerns over carcinogenic side-effects of PPI might be unfounded.

Proton pump inhibitors and the risk of colorectal cancer: a systematic review and meta-analysis of observational studies

PURPOSE

The increased risk of colorectal cancer (CRC) associated with long-term use of proton pump inhibitors (PPIs) has attracted considerable attention; however, the conclusions of studies evaluating this correlation are inconsistent or even controversial. Therefore, we conducted a systematic review and meta-analysis to determine the association of PPI use with the risk of CRC.

METHODS

A systematic literature search was conducted in PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials to identify relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for the associations between PPI use and the risk of CRC were estimated with a fixed-effects or random-effects model.

RESULTS

We identified and included 9 observational studies (3 cohort studies and 6 case-control studies) comprising 1,036,438 participants. Overall, there was no statistically significant association between PPI use and the risk of CRC (pooled OR 1.26, 95% CI: 0.90-1.73; p = 0.166) when PPI exposure was assessed as a binary variable. However, a weak association between long-term use of PPIs and CRC was demonstrated (pooled OR 1.19, 95% CI: 1.09-1.31; p < 0.001) when the cumulative duration of PPI exposure was confined to > 5 years.

CONCLUSIONS

Although the present meta-analysis suggests a weak association between long-term use (> 5 years) of PPIs and CRC, there is not enough statistical power to refute or confirm an association between the use of PPIs and CRC. More high-quality prospective cohort studies are needed to assess this correlation.