Effect of Aspirin on Cancer Chemoprevention in Japanese Patients With Type 2 Diabetes: 10-Year Observational Follow-up of a Randomized Controlled Trial

Aspirin vs Placebo as Adjuvant Therapy for Breast Cancer: The Alliance A011502 Randomized Trial

Importance

Observational studies of survivors of breast cancer and prospective trials of aspirin for cardiovascular disease suggest improved breast cancer survival among aspirin users, but prospective studies of aspirin to prevent breast cancer recurrence are lacking.

Objective

To determine whether aspirin decreases the risk of invasive cancer events among survivors of breast cancer.

Design, Setting, and Participants

A011502, a phase 3, randomized, placebo-controlled, double-blind trial conducted in the United States and Canada with 3020 participants who had high-risk nonmetastatic breast cancer, enrolled participants from 534 sites from January 6, 2017, through December 4, 2020, with follow-up to March 4, 2023.

Interventions

Participants were randomized (stratified for hormone receptor status [positive vs negative], body mass index [≤30 vs >30], stage II vs III, and time since diagnosis [<18 vs ≥18 months]) to receive 300 mg of aspirin (n = 1510) or placebo once daily (n = 1510) for 5 years.

Main Outcomes and Measures

The primary outcome was invasive disease-free survival. Overall survival was a key secondary outcome.

Results

A total of 3020 participants were randomized when the data and safety monitoring committee recommended suspending the study at the first interim analysis because the hazard ratio had crossed the prespecified futility bound. By median follow-up of 33.8 months (range, 0.1-72.6 months), 253 invasive disease-free survival events were observed (141 in the aspirin group and 112 in the placebo group), yielding a hazard ratio of 1.27 (95% CI, 0.99-1.63; P = .06). All invasive disease-free survival events, including death, invasive progression (both distant and locoregional), and new primary events, were numerically higher in the aspirin group, although the differences were not statistically significant. There was no difference in overall survival (hazard ratio, 1.19; 95% CI, 0.82-1.72). Rates of grades 3 and 4 adverse events were similar in both groups.

Conclusion and Relevance

Among participants with high-risk nonmetastatic breast cancer, daily aspirin therapy did not improve risk of breast cancer recurrence or survival in early follow-up. Despite its promise and wide availability, aspirin should not be recommended as an adjuvant breast cancer treatment.

Trial Registration

ClinicalTrials.gov Identifier: NCT02927249.

Low-dose aspirin does not lower the risk of colorectal cancer in patients with type 2 diabetes taking metformin

BACKGROUND

Low-dose aspirin and metformin have been individually associated with a reduced risk of cancer. Whether their concurrent use in adults with type 2 diabetes mellitus (T2DM) is associated with a reduced risk of colorectal cancer (CRC) is unclear.

OBJECTIVE

Among individuals with T2DM taking metformin, we sought to evaluate the association between low-dose aspirin versus no aspirin and the risk of CRC.

METHODS

A multiple-database new-user cohort study of patients with T2DM taking metformin was conducted between 2007 and 2010 (Clinical Data Analysis and Reporting System [CDARS], Hong Kong) and 2007-2016 (The Health Improvement Network [THIN], UK). The primary outcome was incident CRC. Patients were followed from index date of prescription until the earliest occurrence of an outcome of interest, an incident diagnosis of any cancer, death, or until 31 December 2019. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CI). Estimates were pooled using an inverse variance random effects model, and heterogeneity was assessed using I² .

RESULTS

After one-to-one propensity-score matching, 57,534 patients were included (CDARS = 16,276; THIN = 41,258). The median (IQR) follow-up was 9.3 (6.5-10.7) years in CDARS and 3.2 (1.1-5.8) years in THIN. The concurrent use of low-dose aspirin and metformin was not associated with a lower risk of CRC compared to metformin only (HR = 0.89, 95% CI 0.75-1.05, I²  = 0%).

CONCLUSION

Low-dose aspirin was not associated with a lower risk of CRC in patients with T2DM taking metformin. Our study does not support the routine use of low-dose aspirin in this population.

Association between Statins and Incidence of Cancer in Patients with Dyslipidemia Using Large-Scale Health Insurance Claims Data

Recent experimental studies have examined the efficacy of statins in preventing cancer, but the findings of clinical studies are inconsistent, and studies on Japanese patients are limited. This study aimed to clarify the association between statins and cancer risk among Japanese patients. We conducted a large population-based retrospective cohort study using the Japanese health insurance claims database, including patients newly diagnosed with dyslipidemia between 2005 and 2015. Patients who were on newly prescribed statins during the study period were designated as statin users. They were matched 1:1 with randomly selected drug nonusers who were not prescribed drugs for dyslipidemia according to age, sex, and year of first diagnosis of dyslipidemia. There were 23,746 patients in each group. The mean duration of follow-up for statin users and drug nonusers was approximately 2 years. Using a Cox proportional hazards model, significant reduction in cancer risk was observed in statin users compared with that in drug nonusers [adjusted HR = 0.84; 95% confidence interval (CI), 0.72-0.97; adjusted for patient background factors]. The results of subgroup analyses suggested that prescribed statins reduced the incidence of cancer of the digestive organs (adjusted HR = 0.79; 95% CI, 0.63-0.99) as well as reduced cancer risk in patients with nonsmokers (adjusted HR = 0.78, 95% CI = 0.65-0.92). Our results suggest that statin use may reduce cancer risk in patients with dyslipidemia.

PREVENTION RELEVANCE

This study clarified the relationship between statin use and cancer risk in patients with dyslipidemia. Our study will contribute to medicine selection in patients with hypercholesterolemia level. See related Spotlight, p. 1.

Aspirin Use to Prevent Cardiovascular Disease and Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Low-dose aspirin is used for primary cardiovascular disease prevention and may have benefits for colorectal cancer prevention.

OBJECTIVE

To review the benefits and harms of aspirin in primary cardiovascular disease prevention and colorectal cancer prevention to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed, Embase, and the Cochrane Central Register of Controlled Trials through January 2021; literature surveillance through January 21, 2022.

STUDY SELECTION

English-language randomized clinical trials (RCTs) of low-dose aspirin (≤100 mg/d) compared with placebo or no intervention in primary prevention populations.

DATA EXTRACTION AND SYNTHESIS

Single extraction, verified by a second reviewer. Quantitative synthesis using Peto fixed-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Cardiovascular disease events and mortality, all-cause mortality, colorectal cancer incidence and mortality, major bleeding, and hemorrhagic stroke.

RESULTS

Eleven RCTs (N = 134 470) and 1 pilot trial (N = 400) of low-dose aspirin for primary cardiovascular disease prevention were included. Low-dose aspirin was associated with a significant decrease in major cardiovascular disease events (odds ratio [OR], 0.90 [95% CI, 0.85-0.95]; 11 RCTs [n = 134 470]; I2 = 0%; range in absolute effects, -2.5% to 0.1%). Results for individual cardiovascular disease outcomes were significant, with similar magnitude of benefit. Aspirin was not significantly associated with reductions in cardiovascular disease mortality or all-cause mortality. There was limited trial evidence on benefits for colorectal cancer, with the findings highly variable by length of follow-up and statistically significant only when considering long-term observational follow-up beyond randomized trial periods. Low-dose aspirin was associated with significant increases in total major bleeding (OR, 1.44 [95% CI, 1.32-1.57]; 10 RCTs [n = 133 194]; I2 = 4.7%; range in absolute effects, 0.1% to 1.0%) and in site-specific bleeding, with similar magnitude.

CONCLUSIONS AND RELEVANCE

Low-dose aspirin was associated with small absolute risk reductions in major cardiovascular disease events and small absolute increases in major bleeding. Colorectal cancer results were less robust and highly variable.

Chemopreventive Effects of Concomitant or Individual Use of Statins, Aspirin, Metformin, and Angiotensin Drugs: A Study Using Claims Data of 23 Million Individuals

Despite previous studies on statins, aspirin, metformin, and angiotensin-converting-enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs), little has been studied about all their possible combinations for chemoprevention against cancers. This study aimed to comprehensively analyze the composite chemopreventive effects of all the combinations. In this case-control study, health records were retrieved from claims databases of Taiwan’s Health and Welfare Data Science Center. Eligible cases were matched at a 1:4 ratio with controls for age and sex. Both cases and controls were categorized into 16 exposure groups based on medication use. A total of 601,733 cancer cases were identified. Cancer risks (denoted by adjusted odds ratio; 99% confidence interval) were found to be significantly decreased: overall risk of all cancers in statin-alone (0.864; 0.843, 0.886), aspirin-alone (0.949; 0.939, 0.958), and ACEIs/ARBs (0.982; 0.978, 0.985) users; prostate (0.924; 0.889, 0.962) and female breast (0.967; 0.936, 1.000) cancers in metformin-alone users; gastrointestinal, lung, and liver cancers in aspirin and/or ACEIs/ARBs users; and liver cancer (0.433; 0.398, 0.471) in statin users. In conclusion, the results found no synergistic effect of multiple use of these agents on cancer prevention. Use of two (statins and aspirin, statins and metformin, statins and ACEIs/ARBs, and aspirin and ACEIS/ARBs) showed chemopreventive effects in some combinations, while the use of four, in general, did not.

Low-doses of aspirin promote the growth of human PC-9 lung cancer cells through activation of the MAPK family

Aspirin has been reported for its anti-tumor activity, however, there are few studies on its effects in lung cancer. The present study found that aspirin had a dual role in the proliferation of human lung cancer PC-9 (formerly known as PC-14) and A549 cells, and in human colon cancer HCT116 cells. The cells were treated with 0, 1, 2, 4, 8 and 16 mM aspirin for 24-72 h or 7-12 days and cell proliferation was examined by MTT and colony formation assay. In order to explore the relationship between the proliferation-enhancing effect of low-dose aspirin and mitogen-activated protein kinase (MAPK) signaling activation, PC-9 cells were pretreated with 10 µM PD98059 (a specific inhibitor of ERK), SB203580 (a specific inhibitor of p38) and SP600125 (a specific inhibitor of JNK) for 30 min respectively. Western blot assay was performed to detect the activation of MAPK members in PC-9 cells. Cellular apoptosis was detected using flow cytometer-based Annexin V/propidium iodide dual staining. An assessment of MAPK inhibitors was performed to further validate the role of JNK, p38 and ERK in aspirin-promoted PC-9 cell growth. It was demonstrated that aspirin could promote the growth of human PC-9 lung cancer cells and induced MAPK activation at low concentrations. All the MAPK inhibitors tested (PD98059, SB203580 and SP600125) were able to inhibit the aspirin-induced proliferation of PC-9 cells.

Association Between Statins and Cancer Incidence in Diabetes: a Cohort Study of Japanese Patients with Type 2 Diabetes

BACKGROUND

The antitumor effect of statins has been highlighted, but clinical study results remain inconclusive. While patients with diabetes are at high risk of cancer, it is uncertain whether statins are effective for cancer chemoprevention in this population.

OBJECTIVE

This study evaluated the association between statins and cancer incidence/mortality in patients with type 2 diabetes.

DESIGN

This study was a follow-up observational study of the Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial, which was a randomized controlled trial of low-dose aspirin in Japanese patients with type 2 diabetes.

PARTICIPANTS

This study enrolled 2536 patients with type 2 diabetes, age 30-85 years, and no history of atherosclerotic cardiovascular disease, from December 2002 until May 2005. All participants recruited in the JPAD trial were followed until the day of any fatal event or July 2015. We defined participants taking any statin at enrollment as the statin group (n = 650) and the remainder as the no-statin group (n = 1886).

MAIN MEASURES

The primary end point was the first occurrence of any cancer (cancer incidence). The secondary end point was death from any cancer (cancer mortality).

KEY RESULTS

During follow-up (median, 10.7 years), 318 participants developed a new cancer and 123 died as a result. Cancer incidence and mortality were 10.5 and 3.7 per 1000 person-years in the statin group, and 16.8 and 6.3 per 1000 person-years in the no-statin group, respectively. Statin use was associated with significantly reduced cancer incidence and mortality after adjustment for confounding factors (cancer incidence: adjusted hazard ratio [HR], 0.67; 95% CI, 0.49-0.90, P = 0.007; cancer mortality: adjusted HR, 0.60; 95% CI, 0.36-0.98, P = 0.04).

CONCLUSIONS

Statin use was associated with a reduced incidence and mortality of cancer in Japanese patients with type 2 diabetes.

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.

Long-term aspirin use for primary cancer prevention: An updated systematic review and subgroup meta-analysis of 29 randomized clinical trials

Background and objective: Long-term aspirin use for the primary prevention of cancer remains controversial, and variations in the effect of aspirin use on cancer outcomes by aspirin dose, follow-up duration, or study population have never been systematically evaluated. The objective of this study was to evaluate the effect of aspirin on primary cancer prevention and to determine whether the effect differed according to aspirin dose, follow-up duration, or study population.

Materials and methods: Seven electronic databases were searched from inception to September 30, 2019. Randomized clinical trials (RCTs) that compared aspirin use versus no aspirin use in participants without pre-existing cancer and reported cancer outcomes were selected. Data were screened and extracted by different investigators. Analyses were performed using Review Manager 5.3 and Comprehensive Meta-Analysis 2.0. Total cancer incidence was defined as the primary clinical endpoint. Total cancer mortality, all-cause mortality, major bleeding, and total bleeding events were the secondary outcomes. Subgroup analyses were conducted based on aspirin dose, follow-up duration, and study populations.

Results: Twenty-nine RCTs that randomized 200,679 participants were included. Compared with no aspirin, aspirin use was not associated with significant reductions in total cancer incidence (RR = 1.01, 95% CI: 0.97 to 1.04, P = 0.72), total cancer mortality (RR = 1.00, 95% CI: 0.93 to 1.07, P = 0.90), or all-cause mortality (RR = 0.98, 95% CI: 0.94 to 1.02, P =0.31); however, aspirin use was associated with a 44% increase in the risk of major bleeding (RR = 1.44, 95% CI: 1.32 to 1.57, P < 0.00001) and a 52% increase in the risk of total bleeding events (RR = 1.52, 95% CI: 1.33 to 1.74, P < 0.00001). Subgroup analyses demonstrated consistent results.

Conclusions: Long-term aspirin use in individuals without pre-existing cancer was not associated with a significant reduction in total cancer incidence, cancer mortality, or all-cause mortality; however, aspirin use was associated with a significant increase in the risk of bleeding. Therefore, aspirin is not an appropriate choice for the primary cancer prevention.

Repurposing of drugs approved for cardiovascular diseases: Opportunity or mirage?

Drug repurposing is a promising way in drug discovery to identify new therapeutic uses -different from the original medical indication- for existing drugs. It has many advantages over traditional approaches to de novo drug discovery, since it can significantly reduce healthcare costs and development timeline. In this review, we discuss the possible repurposing of drugs approved for cardiovascular diseases, such as β-blockers, angiotensin converting enzyme inhibitors (ACE-Is), angiotensin II receptor blockers (ARBs), statins, aspirin, cardiac glycosides and low-molecular-weight heparins (LMWHs). Indeed, numerous experimental and epidemiological studies have reported promising anti-cancer activities for these drugs. It is worth mentioning, however, that the results of these studies are often controversial and very few data were obtained by controlled prospective clinical trials. Therefore, no final conclusion has yet been reached in this area and no final recommendations can be made. Moreover, β-blockers, ARBs and statins showed promising results in randomised controlled trials (RCTs) where pathological conditions other than cancer were considered. The results obtained have led or may lead to new indications for these drugs. For each drug or class of drugs, the potential molecular mechanisms of action justifying repurposing, results obtained in vitro and in animal models and data from epidemiological and randomized studies are described.

The evidence strength of a meta-analysis of aspirin for primary prevention of cancer

Dr. Tarek Haykal et al. (145:1795-1809, 2019) reported a meta-analysis of aspirin for the primary prevention of cancer in individuals without known cancer. The authors found that aspirin use was not associated with significant reduction in cancer mortality or incidence, but with higher rates of bleeding. The findings of this study added some evidence to the clinical practice. However, several issues might have compromised the strength of the evidence of this systematic review. If the investigators could have further clarified the inclusion and exclusion criteria, included all eligible studies, extracted data more meticulously, and performed more necessary sensitivity analyses to confirm the robustness of their findings, the strength of evidence of this meta-analysis would have been stronger.

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.

Low-dose aspirin can reduce colorectal cancer mortality after surgery: A 10-year follow-up of 13 528 colorectal cancer patients

BACKGROUND AND AIM

The chemopreventive effect of aspirin in colorectal cancer (CRC) is well studied, but its benefit in patients after CRC diagnosis and surgery is unclear. This study aims to investigate the effects of low-dose aspirin use in mortality among CRC patients after surgery.

METHODS

Patients were analyzed in two cohorts: (i) patients taking aspirin before CRC diagnosis and continued or discontinued aspirin after surgery and (ii) patients, who never used aspirin before CRC diagnosis, received or did not receive aspirin after surgery. CRC-related mortality and all-cause mortality were the primary and secondary outcomes. Sub-distribution hazard ratio (SHR) for competing-risk CRC mortality was fitted to adjust for other causes of death; hazard ratio (HR) was used to compare all-cause mortality.

RESULTS

A total of 13 528 CRC patients were included. Among 3292 patients with regular aspirin use before CRC diagnosis, 2658 (80.7%) continued aspirin and 634 (19.3%) discontinued aspirin after surgery. Continuous use of aspirin significantly reduced CRC-related mortality (SHR: 0.69, 95% confidence interval [CI]: 0.59-0.81) and all-cause mortality (HR: 0.61, 95% CI: 0.55-0.68). Among 10 236 patients who did not use aspirin before CRC diagnosis, 1054 patients (10.3%) received aspirin after surgery and 9182 (89.7%) did not. Aspirin initiated after surgery reduced CRC-related mortality (SHR: 0.88, 95% CI: 0.80-0.98) and all-cause mortality (HR: 0.87, 95% CI: 0.81-0.94).

CONCLUSIONS

Irrespective of aspirin use before surgery for CRC, low-dose aspirin after surgery lowers risk of both CRC-related mortality and overall mortality.

Safety and efficacy of aspirin for primary prevention of cancer: a meta-analysis of randomized controlled trials

BACKGROUND

In the United States, cancer is the second leading cause of mortality, and millions more battle cancer worldwide. As such, primary prevention of cancer is a major interest globally. Aspirin has been studied as a primary prevention method for multiple diseases, mainly cardiovascular disease and various forms of cancer. The role of aspirin as a primary prevention of cancer is still controversial and may be more beneficial in certain cancers over others. With rapidly surfacing large randomized controlled trials (RCTs) studying this subject, we aimed to evaluate the efficacy and safety of aspirin as a primary prophylaxis for cancer.

METHODS

A comprehensive electronic database search was conducted for all RCTs that compared aspirin versus placebo for the prevention of any type of disease, and where cancer incidence or mortality was reported. The primary outcome was cancerrelated mortality. Secondary outcomes were cancer incidence, all-cause mortality, major bleeding, any bleeding and gastrointestinal (GI) bleeding. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) using a random-effects model at the longest follow-up period.

RESULTS

We included 16 RCTs with 104,018 total patients, mean age of 60.51 years, mean follow-up of 5.48 years, and a male percentage of 38.72%. We found that aspirin was not associated with a significant reduction of cancer-related mortality compared with placebo (RR 0.99; 95% CI: 0.87-1.12; P = 0.85: I² = 41%). Compared with placebo, aspirin was not associated with significant reduction of all-cause mortality (RR 0.97; 95% CI: 0.92-1.02; P = 0.19; I² = 13%) or cancer incidence (RR: 0.98; 95% CI: 0.92-1.04; P = 0.43; I² = 16%). However, aspirin treatment was associated with significantly increased risks of any bleeding (RR 1.63; 95% CI: 1.31-2.03; P < 0.01), major bleeding (RR 1.41; 95% CI: 1.26-1.57; P < 0.01), and GI bleeding (RR 1.85; 95% CI: 1.38-2.48; P < 0.01) compared with placebo.

CONCLUSION

Our study did not find any significant reductions in cancer-related mortality or cancer incidence when compared aspirin use with placebo or no aspirin. Our study also highlights that the use of aspirin for primary prevention of cancer was found to cause higher rates of bleeding (any bleeding, major bleeding, and GI bleeding) compared to placebo or no aspirin at the longest follow-up period with no significant benefit in cancer primary prevention.

Beyond a chemopreventive reagent, aspirin is a master regulator of the hallmarks of cancer

PURPOSE

Aspirin, one of the most commonly used nonsteroidal anti-inflammatory drugs (NAIDS), not only shows cancer chemoprevention effects but also improves cancer therapeutic effects when combined with other therapies. Studies that focus on aspirin regulation of the hallmarks of cancer and the associated molecular mechanisms facilitate a more thorough understanding of aspirin in mediating chemoprevention and may supply additional information for the development of novel cancer therapeutic agents.

METHODS

The relevant literatures from PubMed have been reviewed in this article.

RESULTS

Current studies have revealed that aspirin regulates almost all the hallmarks of cancer. Within tumor tissue, aspirin suppresses the bioactivities of cancer cells themselves and deteriorates the tumor microenvironment that supports cancer progression. In addition to tumor tissues, blocking of platelet activation also contributes to the ability of aspirin to inhibit cancer progression. In terms of the molecular mechanism, aspirin targets oncogenes and cancer-related signaling pathways and activates certain tumor suppressors.

CONCLUSION

Beyond a chemopreventive agent, aspirin is a master regulator of the hallmarks of cancer.

Bioactive lipid metabolism in platelet "first responder" and cancer biology

Platelets can serve as "first responders" in cancer and metastasis. This is partly due to bioactive lipid metabolism that drives both platelet and cancer biology. The two primary eicosanoid metabolites that maintain platelet rapid response homeostasis are prostacyclin made by endothelial cells that inhibits platelet function, which is counterbalanced by thromboxane produced by platelets during activation, aggregation, and platelet recruitment. Both of these arachidonic acid metabolites are inherently unstable due to their chemical structure. Tumor cells by contrast predominantly make more chemically stable prostaglandin E₂, which is the primary bioactive lipid associated with inflammation and oncogenesis. Pharmacological, clinical, and epidemiologic studies demonstrate that non-steroidal anti-inflammatory drugs (NSAIDs), which target cyclooxygenases, can help prevent cancer. Much of the molecular and biological impact of these drugs is generally accepted in the field. Cyclooxygenases catalyze the rate-limiting production of substrate used by all synthase molecules, including those that produce prostaglandins along with prostacyclin and thromboxane. Additional eicosanoid metabolites include lipoxygenases, leukotrienes, and resolvins that can also influence platelets, inflammation, and carcinogenesis. Our knowledge base and technology are now progressing toward identifying newer molecular and cellular interactions that are leading to revealing additional targets. This review endeavors to summarize new developments in the field.

Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis

IMPORTANCE

The role for aspirin in cardiovascular primary prevention remains controversial, with potential benefits limited by an increased bleeding risk.

OBJECTIVE

To assess the association of aspirin use for primary prevention with cardiovascular events and bleeding.

DATA SOURCES

PubMed and Embase were searched on Cochrane Library Central Register of Controlled Trials from the earliest available date through November 1, 2018.

STUDY SELECTION

Randomized clinical trials enrolling at least 1000 participants with no known cardiovascular disease and a follow-up of at least 12 months were included. Included studies compared aspirin use with no aspirin (placebo or no treatment).

DATA EXTRACTION AND SYNTHESIS

Data were screened and extracted independently by both investigators. Bayesian and frequentist meta-analyses were performed.

MAIN OUTCOMES AND MEASURES

The primary cardiovascular outcome was a composite of cardiovascular mortality, nonfatal myocardial infarction, and nonfatal stroke. The primary bleeding outcome was any major bleeding (defined by the individual studies).

RESULTS

A total of 13 trials randomizing 164 225 participants with 1 050 511 participant-years of follow-up were included. The median age of trial participants was 62 years (range, 53-74), 77 501 (47%) were men, 30 361 (19%) had diabetes, and the median baseline risk of the primary cardiovascular outcome was 9.2% (range, 2.6%-15.9%). Aspirin use was associated with significant reductions in the composite cardiovascular outcome compared with no aspirin (57.1 per 10 000 participant-years with aspirin and 61.4 per 10 000 participant-years with no aspirin) (hazard ratio [HR], 0.89 [95% credible interval, 0.84-0.95]; absolute risk reduction, 0.38% [95% CI, 0.20%-0.55%]; number needed to treat, 265). Aspirin use was associated with an increased risk of major bleeding events compared with no aspirin (23.1 per 10 000 participant-years with aspirin and 16.4 per 10 000 participant-years with no aspirin) (HR, 1.43 [95% credible interval, 1.30-1.56]; absolute risk increase, 0.47% [95% CI, 0.34%-0.62%]; number needed to harm, 210).

CONCLUSIONS AND RELEVANCE

The use of aspirin in individuals without cardiovascular disease was associated with a lower risk of cardiovascular events and an increased risk of major bleeding. This information may inform discussions with patients about aspirin for primary prevention of cardiovascular events and bleeding.