Clopidogrel and Low-Dose Aspirin, Alone or Together, Reduce Risk of Colorectal Cancer

Cancer-Associated Stroke: Thrombosis Mechanism, Diagnosis, Outcome, and Therapeutic Strategies

Cancer can induce hypercoagulability, which may lead to stroke. This occurs when tumor cells activate platelets as part of their growth and metastasis. Tumor cells activate platelets by generating thrombin and expressing tissue factor, resulting in tumor cell-induced platelet aggregation. Histopathological studies of thrombi obtained during endovascular thrombectomy in patients with acute stroke and active cancer have shown a high proportion of platelets and thrombin. This underscores the crucial roles of platelets and thrombin in cancer-associated thrombosis. Cancer-associated stroke typically occurs in patients with active cancer and is characterized by distinctive features. These features include multiple infarctions across multiple vascular territories, markedly elevated blood D-dimer levels, and metastasis. The presence of cardiac vegetations on echocardiography is a robust indicator of cancer-associated stroke. Suspicion of cancer-associated stroke during endovascular thrombectomy arises when white thrombi are detected, particularly in patients with active cancer. Cancer-associated stroke is almost certain when histopathological examination of thrombi shows a very high platelet and a very low erythrocyte composition. Patients with cancer-associated stroke have high risks of mortality and recurrent stroke. However, limited data are available on the optimal treatment regimen for stroke prevention in these patients. Thrombosis mechanism in cancer is well understood, and distinct therapeutic targets involving thrombin and platelets have been identified. Therefore, direct thrombin inhibitors and/or antiplatelet agents may effectively prevent stroke recurrence. Additionally, this strategy has potential benefits in cancer treatment as accumulating evidence suggests that aspirin use reduces cancer progression, metastasis, and cancer-related mortality. However, clinical trials are necessary to assess the efficacy of this strategy involving the use of direct thrombin inhibitors and/or antiplatelet therapies.

Potential beneficial effects of long-term aspirin use on the prevalence of colorectal cancer: a population-based study of the US Nationwide Inpatient Sample

PURPOSE

Whether long-term aspirin usage is associated with colorectal cancer (CRC) risk needs more evidence. The study evaluated the association between long-term aspirin use and prevalence of CRC in a large, nationally representative database.

METHODS

Hospitalized patients aged ≥ 50 years during 2018 were identified in the United States (US) National Inpatient Sample (NIS). Patients without complete information of age, sex, race, income, and insurance status were excluded, as well as those with inflammatory bowel disease (IBD) or malignancies other than CRC. Propensity score matching (PSM) was applied to balance the characteristics between patients with and without long-term aspirin use. Logistic regressions were performed to determine the relationship between long-term aspirin use and the presence of CRC. CRC and aspirin use were identified through the administrative International Classification of Diseases (ICD) codes.

RESULTS

Data from 3,490,226 patients were included, in which 688,018 (19.7%) had a record of long-term aspirin use. After 1:1 PSM, there remained 1,376,006 patients, representing 6,880,029 individuals in the US after weighting. After adjusting for confounders, long-term aspirin use was significantly associated with lower CRC odds (adjusted odds ratio [aOR] = 0.64, 95% confidence interval [CI] 0.62, 0.67). This association was not changed when stratified by age, sex, race, body mass index (BMI), and smoking.

CONCLUSIONS

From a national inpatient dataset, US adults ≥ 50 years on long-term aspirin are less likely to have CRC, regardless of age, sex, race, BMI, and smoking status.

Acetylsalicylic Acid Effect in Colorectal Cancer Taking into Account the Role of Tobacco, Alcohol and Excess Weight

Excess weight, smoking and risky drinking are preventable risk factors for colorectal cancer (CRC). However, several studies have reported a protective association between aspirin and the risk of CRC. This article looks deeper into the relationships between risk factors and aspirin use with the risk of developing CRC. We performed a retrospective cohort study of CRC risk factors and aspirin use in persons aged >50 years in Lleida province. The participants were inhabitants with some medication prescribed between 2007 and 2016 that were linked to the Population-Based Cancer Registry to detect CRC diagnosed between 2012 and 2016. Risk factors and aspirin use were studied using the adjusted HR (aHR) with 95% confidence intervals (CI) using a Cox proportional hazard model. We included 154,715 inhabitants of Lleida (Spain) aged >50 years. Of patients with CRC, 62% were male (HR = 1.8; 95% CI: 1.6-2.2), 39.5% were overweight (HR = 2.8; 95% CI: 2.3-3.4) and 47.3% were obese (HR = 3.0; 95% CI: 2.6-3.6). Cox regression showed an association between aspirin and CRC (aHR = 0.7; 95% CI: 0.6-0.8), confirming a protective effect against CRC and an association between the risk of CRC and excess weight (aHR = 1.4; 95% CI: 1.2-1.7), smoking (aHR = 1.4; 95% CI: 1.3-1.7) and risky drinking (aHR = 1.6; 95% CI: 1.2-2.0). Our results show that aspirin use decreased the risk of CRC and corroborate the relationship between overweight, smoking and risky drinking and the risk of CRC.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

The Function and Regulation of Platelet P2Y12 Receptor

In addition to the key role in hemostasis and thrombosis, platelets have also been wildly acknowledged as immune regulatory cells and involving in the pathogenesis of inflammation-related diseases. Since purine receptor P2Y12 plays a crucial role in platelet activation, P2Y12 antagonists such as clopidogrel, prasugrel, and ticagrelor have been widely used in cardiovascular diseases worldwide in recent decades due to their potent antiplatelet and antithrombotic effects. Meanwhile, the role of P2Y12 in inflammatory diseases has also been extensively studied. Relatively, there are few studies on the regulation of P2Y12. This review first summarizes the various roles of P2Y12 in the process of platelet activation, as well as downstream effects and signaling pathways; then introduces the effects of P2Y12 in inflammatory diseases such as sepsis, atherosclerosis, cancer, autoimmune diseases, and asthma; and finally reviews the current researches on P2Y12 regulation.

Scoping Review on Platelets and Tumor Angiogenesis: Do We Need More Evidence or Better Analysis?

Platelets are an active component of the tumor microenvironment (TME), involved in the regulation of multiple tumor processes, including angiogenesis. They are generated rich in angiogenic factors in their granules to actively participate in the hemostatic process by megakaryocytes and further enriched in angiogenic factors by all components of the tumor microenvironment to control the angiogenic process because of their preferential relationship with the endothelial component of vessels. In recent decades, the literature has reported a great deal of evidence on the role of platelets in tumor angiogenesis; however, it is unclear whether the number or mean volume of platelets and/or their content and localization in TME may have clinical relevance in the choice and management of therapy for the cancer patient. In this scoping review, we collected and critically reviewed the scientific evidence supporting a close relationship between platelets, cancer, and angiogenesis. The aim of this work was to define the landscape of platelet-activated angiogenesis in cancer progression and analyze what and how much evidence is present in the last 20 years in the literature at both the preclinical and clinical levels, to answer whether platelets could be a useful determinant for analyzing tumor angiogenesis. In conclusion, this scoping review indicates that there is much evidence, both preclinical and clinical, but in the preclinical context, studies demonstrate the direct involvement of platelets in tumor angiogenesis; in the clinical context the evidence is indirect, though strong, and the indication of how and to what extent platelet content contributes to tumor angiogenesis is lacking. So, do we need more evidence or better analysis? More molecular and quali-quantitative data is needed to translate the results obtained in preclinical studies into the clinical setting. This information about platelets, if correlated with tumor type and its biology, including tumor vasculature, type of angiogenesis, and patient characteristics (age, sex, comorbidities, drug treatments for chronic diseases) could be an important pa- rameter for correlating platelet biology to angiogenesis, for personalizing cancer therapy, and for clinical prognosis.

Antiplatelet Drugs on the Recurrence of Hepatocellular Carcinoma after Liver Transplantation

Previous studies reported suppressive effects of antiplatelet agents on hepatocellular carcinoma (HCC); however, this has never been assessed in patients who underwent liver transplantation (LT). This retrospective observational study used data from LT recipients with pre-transplant HCC in a single tertiary hospital. The study population was divided into two groups according to the use of antiplatelet agents for >90 days within the study period (377 antiplatelet groups versus 91 non-antiplatelet groups). Matched groups containing 79 patients in each group were also compared regarding HCC-recurrence and HCC-related mortality, which were analyzed by treating non-HCC death as a competing risk. In Kaplan−Meier analyses of the matched cohort, the 5-year cumulative incidences of HCC recurrence and HCC-specific death were similar between the antiplatelet (p = 0.876) and non-antiplatelet groups (p = 0.701). All-cause and non-HCC deaths were also similar between the two groups (p = 0.867 and p = 0.413, respectively). In multivariable analyses of the entire cohort, antiplatelet use was not associated with HCC recurrence (hazard ratio [HR] 1.37, p = 0.300) or HCC-specific death (HR 1.54, p = 0.310). Therefore, unlike the usual setting with liver disease, antiplatelet therapy did not affect HCC recurrence or HCC-specific mortality when used after LT.

Repurposing the Antiplatelet Agent Ticlopidine to Counteract the Acute Phase of ER Stress Condition: An Opportunity for Fighting Coronavirus Infections and Cancer

Different pathological conditions, including viral infections and cancer, can have a massive impact on the endoplasmic reticulum (ER), causing severe damage to the cell and exacerbating the disease. In particular, coronavirus infections, including SARS coronavirus-2 (SARS-CoV-2), responsible for COVID-19, cause ER stress as a consequence of the enormous amounts of viral glycoproteins synthesized, the perturbation of ER homeostasis and the modification of ER membranes. Therefore, ER has a central role in the viral life cycle, thus representing one of the Achilles’ heels on which to focus therapeutic intervention. On the other hand, prolonged ER stress has been demonstrated to promote many pro-tumoral attributes in cancer cells, having a key role in tumor growth, metastasis and response to therapies. In this report, adopting a repurposing approach of approved drugs, we identified the antiplatelet agent ticlopidine as an interferent of the unfolded protein response (UPR) via sigma receptors (SRs) modulation. The promising results obtained suggest the potential use of ticlopidine to counteract ER stress induced by viral infections, such as COVID-19, and cancer.

Pleiotropic effects of clopidogrel

Clopidogrel is a widely prescribed prodrug with anti-thrombotic activity through irreversible inhibition of the P2Y₁₂ receptor on platelets. It is FDA-approved for the clinical management of thrombotic diseases like unstable angina, myocardial infarction, stroke, and during percutaneous coronary interventions. Hepatic clopidogrel metabolism generates several distinct metabolites. Only one of these metabolites is responsible for inhibiting the platelet P2Y₁₂ receptor. Importantly, various non-hemostatic effects of clopidogrel therapy have been described. These non-hemostatic effects are perhaps unsurprising, as P2Y₁₂ receptor expression has been reported in multiple tissues, including osteoblasts, leukocytes, as well as vascular endothelium and smooth muscle. While the "inactive" metabolites have been commonly thought to be biologically inert, recent findings have uncovered P2Y₁₂ receptor-independent effects of clopidogrel treatment that may be mediated by understudied metabolites. In this review, we summarize both the P2Y₁₂ receptor-mediated and non-P2Y₁₂ receptor-mediated effects of clopidogrel and its metabolites in various tissues.

Anticoagulant drugs with or without proton pump inhibitor and colorectal cancer risk: a population-based, case-control study

Background

Low-dose aspirin and clopidogrel have demonstrated potential chemoprevention for colorectal cancer (CRC). Proton-pump inhibitors (PPI) are commonly prescribed with anticoagulation drugs, but the relationship between PPI and CRC is unclear. Moreover, evidence of CRC risk under direct oral anticoagulant (DOAC) is limited. This study aimed to investigate the effects of anticoagulation drugs combined with or without PPI on the risks of CRC in Taiwan.

Methods

A retrospective case–control study of 1,024,227 cases based on the Chang Gung Research Database from 2010 to 2017 was performed. Clinical characteristics, indications, duration of anticoagulation and PPI use, and CRC occurrence data were collected. Logistic regression was employed to adjust for known confounders of CRC risk.

Results

Monotherapy of clopidogrel decreased the risk of CRC (AOR 0.70; 95% CI 0.60–0.83), while no protective effect was observed in aspirin alone or aspirin plus clopidogrel. DOAC did not affect CRC significantly. The risk of CRC increased in patients with PPI (AOR 1.38; 95% CI 1.28–1.49) and PPI plus DOAC (OR 3.91; 95% CI 1.49–10.27), while PPI plus aspirin decreased the risk of CRC (OR 0.48; 95% CI 0.32–0.73). PPI plus clopidogrel showed no significant effect on the CRC.

Conclusion

This study suggests clopidogrel alone and PPI plus aspirin offer a preventative benefit against CRC in the Taiwanese population studied. The same effect was not observed in DOAC. Moreover, a significant increase in CRC was observed in patients on PPI monotherapy and PPI plus DOAC, suggesting a possible risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02314-w.

Intratumoral Platelets: Harmful or Incidental Bystanders of the Tumor Microenvironment?

Simple Summary

The tumor microenvironment (TME) is the complex and heterogenous ecosystem of solid tumors known to influence their growth and their progression. Besides tumor cells, the TME comprises a variety of host-derived cell types, ranging from endothelial cells to fibroblasts and immune cells. Clinical and experimental data are converging to indicate that platelets, originally known for their fundamental hemostatic function, also participate in tumor development and shaping of the TME. Considering the abundance of antiplatelet drugs, understanding if and how platelets contribute to the TME may lead to new therapeutic tools for improved cancer prevention and treatments.

Abstract

The tumor microenvironment (TME) has gained considerable interest because of its decisive impact on cancer progression, response to treatment, and disease recurrence. The TME can favor the proliferation, dissemination, and immune evasion of cancer cells. Likewise, there is accumulating evidence that intratumoral platelets could favor the development and aggressiveness of solid tumors, notably by influencing tumor cell phenotype and shaping the vascular and immune TME components. Yet, in contrast to other tumor-associated cell types like macrophages and fibroblasts, platelets are still often overlooked as components of the TME. This might be due, in part, to a deficit in investigating and reporting the presence of platelets in the TME and its relationships with cancer characteristics. This review summarizes available evidence from clinical and animal studies supporting the notion that tumor-associated platelets are not incidental bystanders but instead integral and active components of the TME. A particular emphasis is given to the description of intratumoral platelets, as well as to the functional consequences and possible mechanisms of intratumoral platelet accumulation.

Statins and Colorectal Cancer Risk: A Population-Based Case-Control Study and Synthesis of the Epidemiological Evidence

(1) Background: The pleiotropic effects of statins may explain a chemoprotective action against colorectal cancer (CRC). Many studies have tested this hypothesis, but results have been inconsistent so far. Moreover, few have examined statins individually which is important for determining whether there is a class effect and if lipophilicity and intensity may play a role. (2) Methods: From 2001–2014, we carried out a study comprised of 15,491 incident CRC cases and 60,000 matched controls extracted from the primary healthcare database BIFAP. We fit a logistic regression model to compute the adjusted-odds ratios (AOR) with their 95% confidence intervals (CIs). Additionally, we carried out a systematic review and meta-analysis. (3) Results: Current use of statins showed a reduced risk of CRC (AOR = 0.87; 95% CI: 0.83–0.91) not sustained after discontinuation. The association was time-dependent, starting early (AOR_{6months–1year} = 0.85; 95% CI: 0.76–0.96) but weakened beyond 3-years. A class effect was suggested, although only significant for simvastatin and rosuvastatin. The risk reduction was more marked among individuals aged 70 or younger, and among moderate-high intensity users. Forty-eight studies were included in the meta-analysis (pooled-effect-size = 0.90; 95% CI: 0.86–0.93). (4) Conclusions: Results from the case-control study and the pooled evidence support a moderate chemoprotective effect of statins on CRC risk, modified by duration, intensity, and age.

Long-term prognosis of laparoscopic gastrectomy for patients on antithrombotic therapy: a retrospective cohort study

PURPOSE

Few studies have reported on the interactions between gastrectomy and antithrombotic therapy, especially the long-term prognosis. We aimed to clarify the short- and long-term prognosis of gastrectomy for patients on antithrombotic therapy.

METHODS

We reviewed the perioperative data and survival rate of patients who underwent laparoscopic distal gastrectomy (LDG) at our institute between 2010 and 2013.

RESULTS

There were 119 patients enrolled in this retrospective study: 31 who were taking antithrombotic drugs (antithrombotic therapy (ATT) group), and 88 who were not (non-ATT group). The mean age was significantly higher in the ATT group than in the non-ATT group. No significant differences were observed in the amount of intraoperative bleeding or blood hemoglobin level after surgery between the groups. Bleeding complications occurred in only one patient from the ATT group, and the postoperative complication rate was comparable between the groups. During follow-up, cerebrovascular or cardiovascular events developed in 19.4% of the ATT group patients and 4.5% of the non-ATT group patients; however, there were no significant differences in the 5-year overall survival rates between the groups (ATT group, 76.9%; non-ATT group, 82.9%).

CONCLUSIONS

Antithrombotic therapy did not affect the short-term or long-term prognosis of patients after LDG.

Antiplatelet Agents Affecting GPCR Signaling Implicated in Tumor Metastasis

Metastasis requires that cancer cells survive in the circulation, colonize distant organs, and grow. Despite platelets being central contributors to hemostasis, leukocyte trafficking during inflammation, and vessel stability maintenance, there is significant evidence to support their essential role in supporting metastasis through different mechanisms. In addition to their direct interaction with cancer cells, thus forming heteroaggregates such as leukocytes, platelets release molecules that are necessary to promote a disseminating phenotype in cancer cells via the induction of an epithelial-mesenchymal-like transition. Therefore, agents that affect platelet activation can potentially restrain these prometastatic mechanisms. Although the primary adhesion of platelets to cancer cells is mainly independent of G protein-mediated signaling, soluble mediators released from platelets, such as ADP, thromboxane (TX) A2, and prostaglandin (PG) E2, act through G protein-coupled receptors (GPCRs) to cause the activation of more additional platelets and drive metastatic signaling pathways in cancer cells. In this review, we examine the contribution of the GPCRs of platelets and cancer cells in the development of cancer metastasis. Finally, the possible use of agents affecting GPCR signaling pathways as antimetastatic agents is discussed.

Combining repurposed drugs to treat colorectal cancer

The drug development process, especially of antineoplastic agents, has become increasingly costly and ineffective. Drug repurposing and drug combination are alternatives to de novo drug development, being low cost, rapid, and easy to apply. These strategies allow higher efficacy, decreased toxicity, and overcoming of drug resistance. The combination of antineoplastic agents is already being applied in cancer therapy, but the combination of repurposed drugs is still under-explored in pre- and clinical development. In this review, we provide a set of pharmacological concepts focusing on drug repurposing for treating colorectal cancer (CRC) and that are relevant for the application of new drug combinations against this disease.

P2Y12 receptor blockers are anti-inflammatory drugs inhibiting both circulating monocytes and macrophages including THP-1 cells

P₂Y₁₂ blockade improves patient outcomes after myocardial infarction. As well as antithrombotic effects, anti-inflammatory effects may contribute to this beneficial clinical outcome. Here we aimed to identify potential anti-inflammatory effects of P₂Y₁₂ receptor blockers on monocytes and macrophages. Using flow cytometry, migration assays, flow chambers and RNA microarrays, we investigated the effects of adenosine diphosphate (ADP) and P₂Y₁₂ receptor blockers on blood monocytes, THP-1 monocytes and THP-1 monocytes after differentiation to macrophages. P₂Y₁₂ -expressing platelets can form aggregates with monocytes in circulating blood. Mediated by platelets, ADP results in activation of the integrin receptor Mac-1 on blood monocytes, as detected by the conformation-specific single-chain antibody MAN-1. Via the same association with platelets, THP-1 monocyte adhesion to the endothelial intercellular adhesion molecule 1 (ICAM-1) is induced by ADP. P₂Y₁₂ receptor blockers prevent these ADP effects on monocytes. Interestingly, in contrast to THP-1 monocytes, THP-1 monocytes, after differentiation to macrophages, directly expressed the P₂Y₁₂ receptor and consequently ADP was found to be a potent chemoattractant. Again, P₂Y₁₂ receptor blockers antagonised this effect. Accordingly, stimulation of THP-1 macrophages with ADP caused a substantial change in gene expression pattern and upregulation of several genes associated with inflammation and atherogenesis. These data establish novel anti-inflammatory effects of P₂Y₁₂ receptor blockers on monocytes and macrophages, which are expected to contribute to cardiovascular risk reduction.

Physiologically relevant aspirin concentrations trigger immunostimulatory cytokine production by human leukocytes

Acetylsalicylic acid is a globally used non-steroidal anti-inflammatory drug (NSAID) with diverse pharmacological properties, although its mechanism of immune regulation during inflammation (especially at in vivo relevant doses) remains largely speculative. Given the increase in clinical perspective of Acetylsalicylic acid in various diseases and cancer prevention, this study aimed to investigate the immunomodulatory role of physiological Acetylsalicylic acid concentrations (0.005, 0.02 and 0.2 mg/ml) in a human whole blood of infection-induced inflammation. We describe a simple, highly reliable whole blood assay using an array of toll-like receptor (TLR) ligands 1–9 in order to systematically explore the immunomodulatory activity of Acetylsalicylic acid plasma concentrations in physiologically relevant conditions. Release of inflammatory cytokines and production of prostaglandin E₂ (PGE₂) were determined directly in plasma supernatant. Experiments demonstrate for the first time that plasma concentrations of Acetylsalicylic acid significantly increased TLR ligand-triggered IL-1β, IL-10, and IL-6 production in a dose-dependent manner. In contrast, indomethacin did not exhibit this capacity, whereas cyclooxygenase (COX)-2 selective NSAID, celecoxib, induced a similar pattern like Acetylsalicylic acid, suggesting a possible relevance of COX-2. Accordingly, we found that exogenous addition of COX downstream product, PGE₂, attenuates the TLR ligand-mediated cytokine secretion by augmenting production of anti-inflammatory cytokines and inhibiting release of pro-inflammatory cytokines. Low PGE₂ levels were at least involved in the enhanced IL-1β production by Acetylsalicylic acid.

Does aspirin reduce the incidence, recurrence, and mortality of colorectal cancer? A meta-analysis of randomized clinical trials

BACKGROUND

Colorectal cancer (CRC) is the third most common diagnosed cancer and the third leading cause of all cancer deaths in the USA. Some evidences are shown that aspirin can reduce the morbidity and mortality of different cancers, including CRC. Aspirin has become a new focus of cancer prevention and treatment research so far; clinical studies, however, found conflicting conclusions of its anti-cancer characteristics. This study is to summarize the latest evidence of correlation between aspirin use and CRC and/or colorectal adenomas.

METHODS

Databases were searched to identify randomized controlled trials (RCTs) in the salvage setting. The pooled relative risk (RR) with 95% confidence interval (CI) was used to estimate the effect of aspirin on colorectal cancer and/or colorectal adenomas. Subgroup analysis and sensitivity analysis were also conducted.

RESULTS

The result showed that aspirin use was not associated with incidence of CRC (RR 0.97; 95% CI 0.84-1.12; P = 0.66; I² = 34%), aspirin use was found to be associated with reduced recurrence of colorectal adenomas (RR 0.83; 95% CI 0.72-0.95; P = 0.006; I² = 63%) and reduced mortality of CRC (RR 0.79; 95% CI 0.64-0.97; P = 0.02; I² = 14%). Subgroup analysis found a statistically significant association in low dose with a pooled RR of 0.85 (95% CI 0.74-0.99; P = 0.03; I² = 31%).

CONCLUSIONS

This meta-analysis of randomized controlled trial data indicates that aspirin reduces the overall risk of recurrence and mortality of CRC and/or colorectal adenomas. Incidence of CRC was also reduced with low-dose aspirin. The emerging evidence on aspirin's cancer protection role highlights an exciting time for cancer prevention through low-cost interventions.

TRIAL REGISTRATION

Clinicaltrials.gov no: CRD42020208852; August 18, 2020; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020208852 ).

Multidisciplinary prevention and management strategies for colorectal cancer and cardiovascular disease

Colorectal cancer (CRC) and cardiovascular disease (CVD) are leading causes of morbidity and mortality worldwide. Their numerous shared and modifiable risk factors underscore the importance of effective prevention strategies for these largely preventable diseases. Conventionally regarded as separate disease entities, clear pathophysiological links and overlapping risk factors represent an opportunity for synergistic collaborative efforts of oncologists and cardiologists. In addition, current CRC treatment approaches can exert cardiotoxicity and thus increase CVD risk. Given the complex interplay of both diseases and increasing numbers of CRC survivors who are at increased risk for CVD, multidisciplinary cardio-oncological approaches are warranted for optimal patient care from primary prevention to acute disease treatment and long-term surveillance.

Antiplatelet Drug Use and Breast Cancer Risk in a Prospective Cohort of Postmenopausal Women

BACKGROUND

Epidemiologic evidence is insufficient to draw conclusions on the impact of low-dose aspirin use on breast cancer risk, and the potential impact of other antiplatelet drugs such as clopidogrel needs to be explored.

METHODS

We investigated the association between breast cancer risk and low-dose aspirin or clopidogrel use in the E3N cohort, which includes 98,995 women, with information on breast cancer risk factors collected from biennial questionnaires matched with drug reimbursement data available from 2004. Women with at least two reimbursements of the drug of interest in any previous 3-month period were considered "ever" exposed. Exposure was considered as time-varying and multivariable Cox regression models were used to estimate HRs of breast cancer.

RESULTS

Among 62,512 postmenopausal women followed during 9 years on average, 2,864 breast cancer cases were identified. Compared with never use, a transient higher breast cancer risk was observed during the third year of low-dose aspirin use [HR2-≤3 years of use = 1.49 (1.08-2.07)], followed by a lower risk [HR4+ years of use = 0.72 (0.52-0.99)]. Clopidogrel ever use was associated with a higher breast cancer risk [HR, 1.30 (1.02-1.68)], restricted to estrogen receptor negative (ER-) tumors [HRER+ = 1.14 (0.83-1.57), HRER- = 3.07 (1.64-5.76), P homogeneity = 0.01].

CONCLUSIONS

Low-dose aspirin was associated with a lower breast cancer risk only after several years of use, while ever use of clopidogrel was associated with a higher ER- breast cancer risk.

IMPACT

Antiplatelet drugs are not good pharmacologic candidates for breast cancer prevention.

ACG Clinical Guidelines: Colorectal Cancer Screening 2021

Colorectal cancer (CRC) is the third most common cancer in men and women in the United States. CRC screening efforts are directed toward removal of adenomas and sessile serrated lesions and detection of early-stage CRC. The purpose of this article is to update the 2009 American College of Gastroenterology CRC screening guidelines. The guideline is framed around several key questions. We conducted a comprehensive literature search to include studies through October 2020. The inclusion criteria were studies of any design with men and women age 40 years and older. Detailed recommendations for CRC screening in average-risk individuals and those with a family history of CRC are discussed. We also provide recommendations on the role of aspirin for chemoprevention, quality indicators for colonoscopy, approaches to organized CRC screening and improving adherence to CRC screening. CRC screening must be optimized to allow effective and sustained reduction of CRC incidence and mortality. This can be accomplished by achieving high rates of adherence, quality monitoring and improvement, following evidence-based guidelines, and removing barriers through the spectrum of care from noninvasive screening tests to screening and diagnostic colonoscopy. The development of cost-effective, highly accurate, noninvasive modalities associated with improved overall adherence to the screening process is also a desirable goal.

Concurrent Aspirin Use Is Associated with Improved Outcome in Rectal Cancer Patients Who Undergo Chemoradiation Therapy

BACKGROUND

The benefit of aspirin in rectal cancer during chemoradiation therapy (CRT) and the factors affecting its efficacy are not well characterized. We compared the outcomes of rectal patients undergoing neoadjuvant CRT based on aspirin use.

METHODS

Patients undergoing CRT for rectal cancer from 2010 to 2018 were evaluated. Aspirin use was determined by medication list prior to treatment. RNA sequencing and subsequent gene set enrichment analysis was performed on surgically resected specimens.

RESULTS

147 patients underwent neoadjuvant CRT with a median follow-up of 38.2 months. Forty-two patients were taking aspirin prior to CRT. Aspirin users had significantly less local and distant progression, and improved progression-free and overall survival. On RNA-sequencing, neither PI3KCA nor KRAS mutational status were associated with the benefit of aspirin use or tumor downstaging. PTGS2/COX2 expression trended lower in aspirin users, but not with tumor response. Aspirin use was associated with increases of M1 macrophages, plasma cells, CD8+ T cells, and reduction of M2 macrophages in the resected tumor.

CONCLUSIONS

Concurrent aspirin use during neoadjuvant CRT was associated with improved local and distant tumor control leading to significantly improved survival. Neither mutations in KRAS or PI3CKA, nor the levels of COX-2 expression at the time of resection of the residual tumor were predictive of these aspirin benefits.

P2Y receptors for extracellular nucleotides: Contributions to cancer progression and therapeutic implications

Purinergic receptors for extracellular nucleotides and nucleosides contribute to a vast array of cellular and tissue functions, including cell proliferation, intracellular and transmembrane ion flux, immunomodulation and thrombosis. In mammals, the purinergic receptor system is composed of G protein-coupled P1 receptors A₁, A_2A, A_2B and A₃ for extracellular adenosine, P2X1-7 receptors that are ATP-gated ion channels and G protein-coupled P2Y_{1,2,4,6,11,12,13 and 14} receptors for extracellular ATP, ADP, UTP, UDP and/or UDP-glucose. Recent studies have implicated specific P2Y receptor subtypes in numerous oncogenic processes, including cancer tumorigenesis, metastasis and chemotherapeutic drug resistance, where G protein-mediated signaling cascades modulate intracellular ion concentrations and activate downstream protein kinases, Src family kinases as well as numerous mitogen-activated protein kinases. We are honored to contribute to this special issue dedicated to the founder of the field of purinergic signaling, Dr. Geoffrey Burnstock, by reviewing the diverse roles of P2Y receptors in the initiation, progression and metastasis of specific cancers with an emphasis on pharmacological and genetic strategies employed to delineate cell-specific and P2Y receptor subtype-specific responses that have been investigated using in vitro and in vivo cancer models. We further highlight bioinformatic and empirical evidence on P2Y receptor expression in human clinical specimens and cover clinical perspectives where P2Y receptor-targeting interventions may have therapeutic relevance to cancer treatment.

Multifaceted Functions of Platelets in Cancer: From Tumorigenesis to Liquid Biopsy Tool and Drug Delivery System

Platelets contribute to several types of cancer through plenty of mechanisms. Upon activation, platelets release many molecules, including growth and angiogenic factors, lipids, and extracellular vesicles, and activate numerous cell types, including vascular and immune cells, fibroblasts, and cancer cells. Hence, platelets are a crucial component of cell-cell communication. In particular, their interaction with cancer cells can enhance their malignancy and facilitate the invasion and colonization of distant organs. These findings suggest the use of antiplatelet agents to restrain cancer development and progression. Another peculiarity of platelets is their capability to uptake proteins and transcripts from the circulation. Thus, cancer-patient platelets show specific proteomic and transcriptomic expression patterns, a phenomenon called tumor-educated platelets (TEP). The transcriptomic/proteomic profile of platelets can provide information for the early detection of cancer and disease monitoring. Platelet ability to interact with tumor cells and transfer their molecular cargo has been exploited to design platelet-mediated drug delivery systems to enhance the efficacy and reduce toxicity often associated with traditional chemotherapy. Platelets are extraordinary cells with many functions whose exploitation will improve cancer diagnosis and treatment.

Association Between Low-Dose Aspirin Use and Colorectal Cancer Incidence in Taiwan

IMPORTANCE

Population-based East Asian data have corroborated reports from non-Asian settings on the association between low-dose aspirin and a lower risk of colorectal cancer (CRC).

OBJECTIVE

To evaluate the association between duration and recency of low-dose aspirin use and CRC risk.

DESIGN, SETTING, AND PARTICIPANTS

This nested case-control study included individuals who initiated aspirin use and matched individuals who did not use aspirin. Data were collected from Taiwan National Health Insurance and Taiwan Cancer Registry from 2000 through 2015. CRC cases were age- and sex-matched in a 1:4 ratio with individuals in a control group, identified from a cohort of individuals who used and did not use aspirin through risk-set sampling. Data analysis was conducted from June 2018 to July 2019.

EXPOSURES

Low-dose aspirin use was defined as receiving less than 150 mg per day, whereas 100 mg/d was most commonly used. Based on duration and recency of low-dose aspirin use between cohort entry (initiation date of low-dose aspirin for aspirin use group or randomly assigned date for those who did not use aspirin) and index date (CRC diagnosis date for individuals in the case group and the diagnosis date for the 4 corresponding matched individuals in the control group), the 3 following mutually exclusive exposure groups served as the basis for analysis: (1) long-term current low-dose aspirin use, (2) episodic low-dose aspirin use, and (3) no low-dose aspirin use (the reference group).

MAIN OUTCOMES AND MEASURES

CRC risk among the 3 exposure groups.

RESULTS

Among 4 710 504 individuals (2 747 830 [51.7%] men; median [interquartile range] age at cohort entry in initiator group, 61 [52-71] years; median [interquartile range] age at cohort entry in nonuse group, 59 [51-68] years), 79 095 CRC cases (1.7% of study cohort) were identified. Compared with no low-dose aspirin use, the adjusted odds ratio (OR) for long-term current low-dose aspirin use and CRC risk was 0.89 (95% CI, 0.85-0.93); for episodic use, 0.88 (95% CI, 0.86-0.89). Adjusted ORs of 0.69 (95% CI, 0.63-0.76) and 0.64 (95% CI, 0.61-0.67) were observed for long-term current use and episodic low-dose aspirin use within the subcohort of individuals who initiated low-dose aspirin between age 40 and 59 years.

CONCLUSIONS AND RELEVANCE

In this study, low-dose aspirin use was associated with 11% lower CRC risk in an East Asian population, and this association was larger when low-dose aspirin use started before age 60 years.

Antiplatelet Therapy Improves the Prognosis of Patients with Hepatocellular Carcinoma

Simple Summary

Antiplatelet therapy shows antitumor effect in several types of cancers. In liver disease, antiplatelet therapy reduces liver fibrosis and occurrence of HCC. However, the effect after diagnosis of hepatocellular carcinoma is still unknown. Therefore, we aimed to clarify the effects of antiplatelet therapy for HCC patients in this study. We compared patients with and without antiplatelet therapy in overall survival, liver-related death, tumor progression, Child-Pugh deterioration and bleeding. Our results suggested that antiplatelet therapy had antitumor effect, liver protective effect and safety. Therefore, patients with antiplatelet therapy could reduce liver-related death and improve overall survival.

Abstract

Aims: Antiplatelet therapy has been reported to reduce liver fibrosis and hepatocellular carcinoma (HCC), and has exhibited antitumor properties in other cancers. However, the effects of antiplatelet therapy after diagnosis of HCC are unknown. We investigated the effects of antiplatelet therapy on prognosis, tumor progression, liver function and safety in HCC patients. Methods: We retrospectively analyzed 772 HCC patients. Antiplatelet therapy was defined as the regular intake of aspirin or clopidogrel from HCC diagnosis through to an endpoint of either overall survival (OS) or liver-related death. Overall survival, liver-related death, tumor progression, Child–Pugh deterioration and hemorrhage were analyzed for patients who either had or had not undertaken antiplatelet therapy. Results: The numbers of patients who did and did not undertake antiplatelet therapy were 111 and 661, respectively. Patients who undertook antiplatelet therapy were older and had better liver function at diagnosis. Antiplatelet therapy resulted in significant improvements in OS (p < 0.01) and lower risk of liver-related death (p < 0.01). Multivariate Cox regression analysis revealed that antiplatelet therapy had a significant negative association with liver-related death (hazard ratio (HR): 0.64, 95% confidence interval (CI): 0.44–0.93, p = 0.02). In patients who underwent transcatheter arterial chemoembolization (TACE) as the first treatment, antiplatelet therapy prevented tumor progression (p < 0.01) and Child–Pugh deterioration (p < 0.01). Antiplatelet therapy did not increase the risk of hemorrhagic events. Conclusions: Antiplatelet therapy reduced liver-related death and improved OS safely in HCC patients.

Low-dose aspirin and risk of gastric and oesophageal cancer: A population-based study in the United Kingdom using The Health Improvement Network

There is increasing interest regarding potential protective effects of low‐dose aspirin against various gastrointestinal cancers. We aimed to quantify the association between use of low‐dose aspirin and risk of gastric/oesophageal cancer using a population‐based primary care database in the UK. Between January 2005 and December 2015, we identified a cohort of 223 640 new users of low‐dose aspirin (75‐300 mg/day) and a matched cohort of nonusers at the start of follow‐up from The Health Improvement Network. Cohorts were followed to identify incident cases of gastric/oesophageal cancer. Nested case‐control analyses were conducted and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for current vs nonuse of low‐dose aspirin using logistic regression. Current use was defined as when low‐dose aspirin lasted 0 to 90 days before the index date (event date for cases, random date for controls) and previous duration was ≥1 year. We identified 727 incident cases of gastric cancer and 1394 incident cases of oesophageal cancer. ORs (95% CIs) were 0.46 (0.38‐0.57) for gastric cancer and 0.59 (0.51‐0.69) for oesophageal cancer. The effect remained consistent with no clear change seen between previous duration of low‐dose aspirin use of 1‐3, 3‐5 or >5 years. The reduced risks was seen with 75 mg/day, and effects were consistent in lag‐time analyses. In conclusion, our results indicate that use of low‐dose aspirin is associated with a 54% reduced risk of gastric cancer and a 41% reduced risk of oesophageal cancer as supported by mechanistic data.

What's new?

Low‐dose aspirin may help protect against the development of gastric and oesophageal cancers. This population‐based study using data from primary care electronic health records in the United Kingdom lends further support to that idea. Compared with no use of low‐dose aspirin, daily use of low‐dose aspirin (75–300 mg) for at least one year was associated with a 54 percent reduction in gastric cancer risk and a 41 percent reduction in oesophageal cancer risk. No clear difference in effect was observed between low‐dose aspirin use for one to three years versus more than three years.

P2Y12 Inhibition beyond Thrombosis: Effects on Inflammation

The P2Y₁₂ receptor is a key player in platelet activation and a major target for antithrombotic drugs. The beneficial effects of P2Y₁₂ receptor antagonists might, however, not be restricted to the primary and secondary prevention of arterial thrombosis. Indeed, it has been established that platelet activation also has an essential role in inflammation. Additionally, nonplatelet P2Y₁₂ receptors present in immune cells and vascular smooth muscle cells might be effective players in the inflammatory response. This review will investigate the biological and clinical impact of P2Y₁₂ receptor inhibition beyond its platelet-driven antithrombotic effects, focusing on its anti-inflammatory role. We will discuss the potential molecular and cellular mechanisms of P2Y₁₂-mediated inflammation, including cytokine release, platelet–leukocyte interactions and neutrophil extracellular trap formation. Then we will summarize the current evidence on the beneficial effects of P2Y₁₂ antagonists during various clinical inflammatory diseases, especially during sepsis, acute lung injury, asthma, atherosclerosis, and cancer.

Chemoprevention of Colorectal Cancer

Although colorectal cancer (CRC) screening has reduced the incidence of and mortality from CRC, chemoprevention strategies have the potential to further reduce CRC incidence and mortality. Chemoprevention agents might be used for average-risk as well as high-risk groups, and to prevent CRC recurrence after therapy. CRC chemoprevention agents that have been studied include aspirin, nonaspirin nonsteroidal anti-inflammatory drugs, statins, agents that target metabolic pathways, and vitamins and minerals. We review the prospect of chemoprevention of CRC, results from preclinical and human studies, challenges, and future directions.

Reviewing the role of P2Y receptors in specific gastrointestinal cancers

Extracellular nucleotides are important intercellular signaling molecules that were found enriched in the tumor microenvironment. In fact, interfering with G protein-coupled P2Y receptor signaling has emerged as a promising therapeutic alternative to treat aggressive and difficult-to-manage cancers such as those affecting the gastrointestinal system. In this review, we will discuss the functions of P2Y receptors in gastrointestinal cancers with an emphasis on colorectal, hepatic, and pancreatic cancers. We will show that P2Y2 receptor up-regulation increases cancer cell proliferation, tumor growth, and metastasis in almost all studied gastrointestinal cancers. In contrast, we will present P2Y6 receptor as having opposing roles in colorectal cancer vs. gastric cancer. In colorectal cancer, the P2Y6 receptor induces carcinogenesis by inhibiting apoptosis, whereas P2Y6 suppresses gastric cancer tumor growth by reducing β-catenin transcriptional activity. The contribution of the P2Y11 receptor in the migration of liver and pancreatic cancer cells will be compared to its normal inhibitory function on this cellular process in ciliated cholangiocytes. Hence, we will demonstrate that the selective inhibition of the P2Y12 receptor activity in platelets was associated to a reduction in the risk of developing colorectal cancer and metastasis formation. We will succinctly review the role of P2Y1, P2Y4, P2Y13, and P2Y14 receptors as the knowledge for these receptors in gastrointestinal cancers is sparse. Finally, redundant ligand selectivity, nucleotide high lability, cell context, and antibody reliability will be presented as the main difficulties in defining P2Y receptor functions in gastrointestinal cancers.

Antiplatelet Agents for Cancer Prevention: Current Evidences and Continuing Controversies

Over the past two decades, aspirin has emerged as a promising chemoprotective agent to prevent colorectal cancer (CRC). In 2016, the mounting evidence supporting its chemoprotective effect, from both basic science and clinical research, led the US Preventive Services Task Force to recommend regular use of low-dose aspirin in some subgroups of patients for whom the benefits are deemed to outweigh the risks. In contrast, data on the chemoprotective effect of aspirin against other cancers are less clear and remain controversial. Most data come from secondary analyses of cardiovascular prevention trials, with only a limited number reporting cancer outcomes as a prespecified endpoint, and overall unclear findings. Moreover, the potential chemoprotective effect of aspirin against other cancers has been recently questioned with the publication of 3 long-awaited trials of aspirin in the primary prevention of cardiovascular diseases reporting no benefit of aspirin on overall cancer incidence and cancer-related mortality. Data on the chemoprotective effects of other antiplatelet agents remain scarce and inconclusive, and further research to examine their benefit are warranted. In this narrative review, we summarize current clinical evidence and continuing controversies on the potential chemoprotective properties of antiplatelet agents against cancer.

Effects of Aspirin or Clopidogrel on Colorectal Cancer Chemoprevention in Patients with Type 2 Diabetes Mellitus

Background: The effect of clopidogrel, whose mechanism of action differs from that of aspirin, on CRC risk remains unknown. We investigated the effects of clopidogrel and aspirin, either as monotherapy or combined, on colorectal cancer (CRC) risk in patients with Type 2 diabetes mellitus (T2DM). Methods: We conducted a cohort study using Taiwan National Health Insurance Research Database. Four groups comprising 218,903 patients using aspirin monotherapy, 20,158 patients using clopidogrel monotherapy, 42,779 patients using dual antiplatelet therapy, and 281,840 nonuser matched controls were created using propensity score matching. Cox proportional hazards regression was used to evaluate the CRC risk during follow-up. Results: During the 13-year follow-up period, we found 9431 cases of CRC over 3,409,522 person-years. The overall incidence rates of CRC were 2.04, 3.45, 1.55, and 3.52 per 1000 person-years in the aspirin, clopidogrel, dual antiplatelet, and nonuser cohorts, respectively. The adjusted hazard ratios (aHRs) were 0.59 (95% confidence interval [CI], 0.56–0.61), 0.77 (95% CI, 0.68–0.87), and 0.37 (95% CI, 0.33–0.40) for the aspirin, clopidogrel, and dual antiplatelet cohorts, respectively. Dose- and duration-dependent chemopreventive effects were observed in the three cohorts.

Are Platelets the Primary Target of Aspirin's Remarkable Anticancer Activity?

Aspirin, when administered at low doses, has emerged as a powerful anticancer drug due to both chemopreventive activity against many forms of cancer and its ability to block metastases when administered postdiagnosis. Platelets, which are often elevated in circulation during the latter stages of cancer, are known to promote epithelial-mesenchymal transition, cancer cell growth, survival in circulation, and angiogenesis at sites of metastases. Low-dose aspirin has been demonstrated to block this procarcinogenic action of platelets. In this article, we present evidence that aspirin's unique ability to irreversibly inhibit platelet cyclooxygenase-1 is a key mechanism by which aspirin exerts anticancer activity.