Impact of aspirin on clinical outcomes for African American men with prostate cancer undergoing radiation

Effect of aspirin on incidence, recurrence, and mortality in prostate cancer patients: integrating evidence from randomized controlled trials and real-world studies

PURPOSE

Aspirin has been suggested to reduce the risk of cancer. However, previous studies have been inconsistent regarding the relationship between aspirin use and the risk of occurrence of prostate cancer (PCa). The purpose of this study was to assess the effect of aspirin on clinical outcomes in patients with PCa in a meta-analysis and to explore the possible dose-response relationship.

METHODS

A systematic literature search was conducted in 10 electronic databases and 4 registries. The combined relative risks (RRs) were calculated using a random-effects model with 95% confidence interval (CIs) to assess the effect of aspirin on the risk of PCa. Relevant subgroup analyses and sensitivity analyses were performed.

RESULTS

The across studies results show that aspirin use associated with lower incidence of PCa (RR: 0.96, 95% CI: 0.95-0.98), and reduced mortality (RR: 0.88, 95% CI: 0.82-0.95). The results of the subgroup analysis indicated that both cohort and population studies in the Americas showed a reduction in PCa incidence and mortality with aspirin use. A linear correlation was observed between dosage/duration of aspirin use and its protective effect. Additionally, post-diagnosis aspirin use was associated with decreased risk of PCa mortality.

CONCLUSIONS

This meta-analysis revealed an independent correlation between the use of aspirin and reductions in both the incidence and mortality rates of PCa. However, randomized controlled trials did not find any association between aspirin use and PCa. Furthermore, the impact of aspirin on PCa occurrence was found to be dependent on both dosage and duration.

Aspirin and cancer survival: a systematic review and meta-analyses of 118 observational studies of aspirin and 18 cancers

BACKGROUND

Despite the accumulation of research papers on aspirin and cancer, there is doubt as to whether or not aspirin is an acceptable and effective adjunct treatment of cancer. The results of several randomised trials are awaited, and these should give clear evidence on three common cancers: colon, breast and prostate. The biological effects of aspirin appear likely however to be of relevance to cancer generally, and to metastatic spread, rather than just to one or a few cancers, and there is already a lot of evidence, mainly from observational studies, on the association between aspirin and survival in a wide range of cancers.

AIMS

In order to test the hypothesis that aspirin taking is associated with an increase in the survival of patients with cancer, we conducted a series of systematic literature searches to identify clinical studies of patients with cancer, some of whom took aspirin after having received a diagnosis of cancer.

RESULTS

Three literature searches identified 118 published observational studies in patients with 18 different cancers. Eighty-one studies report on aspirin and cancer mortality and 63 studies report on all-cause mortality. Within a total of about a quarter of a million patients with cancer who reported taking aspirin, representing 20%-25% of the total cohort, we found aspirin to be associated with a reduction of about 20% in cancer deaths (pooled hazard ratio (HR): 0.79; 95% confidence intervals: 0.73, 0.84 in 70 reports and a pooled odds ratio (OR): 0.67; 0.45, 1.00 in 11 reports) with similar reductions in all-cause mortality (HR: 0.80; 0.74, 0.86 in 56 studies and OR: 0.57; 0.36, 0.89 in seven studies). The relative safety of aspirin taking was examined in the studies and the corresponding author of every paper was written to asking for additional information on bleeding. As expected, the frequency of bleeding increased in the patients taking aspirin, but fatal bleeding was rare and no author reported a significant excess in fatal bleeds associated with aspirin. No author mentioned cerebral bleeding in the patients they had followed.

CONCLUSIONS

There is a considerable body of evidence suggestive of about a 20% reduction in mortality in patients with cancer who take aspirin, and the benefit appears not to be restricted to one or a few cancers. Aspirin, therefore, appears to deserve serious consideration as an adjuvant treatment of cancer, and patients with cancer, and their carers, have a right to be informed of the available evidence.

Immune Inflammation Pathways as Therapeutic Targets to Reduce Lethal Prostate Cancer in African American Men

Despite substantial improvements in cancer survival, not all population groups have benefitted equally from this progress. For prostate cancer, men of African descent in the United States and England continue to have about double the rate of fatal disease compared to other men. Studies suggest that when there is equal access to care, survival disparities are greatly diminished. However, notable differences exist in prostate tumor biology across population groups. Ancestral factors and disparate exposures can lead to altered tumor biology, resulting in a distinct disease etiology by population group. While equal care remains the key target to improve survival, additional efforts should be made to gain comprehensive knowledge of the tumor biology in prostate cancer patients of African descent. Such an approach may identify novel intervention strategies in the era of precision medicine. A growing body of evidence shows that inflammation and the immune response may play a distinct role in prostate cancer disparities. Low-grade chronic inflammation and an inflammatory tumor microenvironment are more prevalent in African American patients and have been associated with adverse outcomes. Thus, differences in activation of immune-inflammatory pathways between African American and European American men with prostate cancer may exist. These differences may influence the response to immune therapy which is consistent with recent observations. This review will discuss mechanisms by which inflammation may contribute to the disparate outcomes experienced by African American men with prostate cancer and how these immunogenic and inflammatory vulnerabilities could be exploited to improve their survival.

An overview of cancer health disparities: new approaches and insights and why they matter

Cancer health disparities remain stubbornly entrenched in the US health care system. The Affordable Care Act was legislation to target these disparities in health outcomes. Expanded access to health care, reduction in tobacco use, uptake of other preventive measures and cancer screening, and improved cancer therapies greatly reduced cancer mortality among women and men and underserved communities in this country. Yet, disparities in cancer outcomes remain. Underserved populations continue to experience an excessive cancer burden. This burden is largely explained by health care disparities, lifestyle factors, cultural barriers, and disparate exposures to carcinogens and pathogens, as exemplified by the COVID-19 epidemic. However, research also shows that comorbidities, social stress, ancestral and immunobiological factors, and the microbiome, may contribute to health disparities in cancer risk and survival. Recent studies revealed that comorbid conditions can induce an adverse tumor biology, leading to a more aggressive disease and decreased patient survival. In this review, we will discuss unanswered questions and new opportunities in cancer health disparity research related to comorbid chronic diseases, stress signaling, the immune response, and the microbiome, and what contribution these factors may have as causes of cancer health disparities.

The multiple effects of aspirin in prostate cancer patients

Aspirin is a commonly used medication with anti-inflammatory and analgesic properties, and it is widely used to reduce the risk of ischaemic heart disease-related events and/or cerebrovascular accidents. However, there is also evidence from epidemiological and interventional studies to suggest that regular aspirin use can reduce the risk of prostate cancer development and progression, and can reduce the risk of disease recurrence following anti-prostate cancer therapy. Aspirin use in African-American men is associated with a reduced incidence of advanced PCa and reduced disease recurrence, and there is evidence from other studies of an association between regular aspirin use and decreased PCa-related mortality. The cyclooxygenase-2 enzyme inhibited by Aspirin and other NSAIDs, and which catalyses prostaglandin synthesis and mediates inflammation, is overexpressed in prostate cancer, therefore inhibition of cyclooxygenase-2 may have direct, and indirect, therapeutic effects. This review explores the evidence suggesting that aspirin use can modify prostate cancer biology and disease characteristics, and explores the potential mechanisms underpinning the observed associations between aspirin use and modification of prostate cancer risk. It also summarises the potential for adjuvant aspirin use to combine with other therapeutic approaches such as radical surgery and radiotherapy.

Repurposing Drugs for Cancer Radiotherapy: Early Successes and Emerging Opportunities

It has long been recognized that combining radiotherapy with cytotoxic drugs such as cisplatin can improve efficacy. However, while concurrent chemoradiotherapy improves patient outcomes, it comes at costs of increased toxicity. A tremendous opportunity remains to investigate drug combinations in the clinical setting that might increase the benefits of radiation without additional toxicity. This chapter highlights opportunities to apply repurposing of drugs along with a mechanistic understanding of radiation effects on cancer and normal tissue to discover new therapy-modifying drugs and help rapidly translate them to the clinic. We survey candidate radiosensitizers that alter DNA repair, decrease hypoxia, block tumor survival signaling, modify tumor metabolism, block growth factor signaling, slow tumor invasiveness, impair angiogenesis, or stimulate antitumor immunity. Promising agents include widely used drugs such as aspirin, metformin, and statins, offering the potential to improve outcomes, decrease radiation doses, and lower costs. Many other candidate drugs are also discussed.

Aspirin Exposure and Mortality Risk among Prostate Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Prostate cancer (PCa) is the ninth most common cause of cancer death globally. Many studies have investigated aspirin exposure and mortality risk among PCa patients, returning inconsistent results. We conducted a comprehensive meta-analysis to explore the association between aspirin exposure and mortality risk among PCa patients and to investigate potential dose/duration/frequency-response relationships.

METHODS AND RESULTS

Studies published from 1980 to 2018 of PubMed and EMBASE databases were searched. We included 14 studies with 110,000 participants. Multivariate-adjusted odds ratios (ORs) were pooled using random-effect models. Potential dose/duration/frequency-response relationships were evaluated for aspirin exposure and prostate cancer-specific mortality (PCSM) risk. We did not detect an association between the highest aspirin exposure and mortality risk (PCSM of prediagnostic aspirin exposure, OR: 0.96, 95% confidence interval [CI]: 0.87-1. 07, I2= 0%; PCSM of postdiagnostic aspirin exposure, OR:0.92, 95% CI: 0.77-1.10, I2 = 56.9%; all-cause mortality [ACM] of prediagnostic aspirin exposure, OR: 0.96, 95% CI: 0.88-1.04, I2 = 9.4%; ACM of postdiagnostic aspirin exposure, OR: 0.95, 95% CI: 0.73-1.23, I2 = 88.9%). There was no significant dose/frequency-response association observed for aspirin exposure and PCSM risk. On duration-response analysis, we found that short-term postdiagnostic aspirin exposure (shorter than 2.5 years) increased the risk of PCSM.

CONCLUSIONS

Our meta-analysis suggests that there is no association between aspirin exposure and PCSM risk. Nor is there an association between the highest aspirin exposure and ACM risk among PCa patients. More studies are needed for a further dose/duration/frequency-response meta-analysis.

Salicylate enhances the response of prostate cancer to radiotherapy

BACKGROUND

Radiotherapy (RT) is a key therapeutic modality for prostate cancer (PrCa), but RT resistance necessitates dose-escalation, often causing bladder and rectal toxicity. Aspirin, a prodrug of salicylate (SAL), has been associated with improved RT response in clinical PrCa cases, but the potential mechanism mediating this effect is unknown. SAL activates the metabolic stress sensor AMP-activated protein kinase (AMPK), which inhibits de novo lipogenesis, and protein synthesis via inhibition of Acetyl-CoA Carboxylase (ACC), and the mammalian Target of Rapamycin (mTOR), respectively. RT also activates AMPK through a mechanism distinctly different from SAL. Therefore, combining these two therapies may have synergistic effects on suppressing PrCa. Here, we examined the potential of SAL to enhance the response of human PrCa cells and tumors to RT.

METHODS

Androgen-insensitive (PC3) and -sensitive (LNCaP) PrCa cells were subjected to proliferation and clonogenic survival assays after treatment with clinically relevant doses of SAL and RT. Balb/c nude mice with PC3 xenografts were fed standard chow diet or chow diet supplemented with 2.5 g/kg salsalate (SAL pro-drug dimer) one week prior to a single dose of 0 or 10 Gy RT. Immunoblotting analysis of signaling events in the DNA repair and AMPK-mTOR pathways and lipogenesis were assessed in cells treated with SAL and RT.

RESULTS

SAL inhibited proliferation and clonogenic survival in PrCa cells and enhanced the inhibition mediated by RT. Salsalate, added to diet, enhanced the anti-tumor effects of RT in PC3 tumor xenografts. RT activated genotoxic stress markers and the activity of mTOR pathway and AMPK and mediated inhibitory phosphorylation of ACC. Interestingly, SAL enhanced the effects of RT on AMPK and ACC but blocked markers of mTOR activation.

CONCLUSIONS

Our results show that SAL can enhance RT responses in PrCa. Salsalate is a promising agent to investigate this concept in prospective clinical trials of PrCa in combination with RT.

K. J, Lanas A. Systematic review update of observational studies further supports aspirin role in cancer treatment: Time to share evidence and decision-making with patients?

BACKGROUND

Evidence is growing that low-dose aspirin used as an adjuvant treatment of cancer is associated with an increased survival and a reduction in metastatic spread. We therefore extended up to August 2017 an earlier systematic search and meta-analyses of published studies of low-dose aspirin taken by patients with a diagnosis of cancer.

METHODS

Searches were completed in Medline and Embase to August 2017 using a pre-defined search strategy to identify reports of relevant studies. References in all the selected papers were scanned. Two reviewers independently applied pre-determined eligibility criteria and extracted data on cause-specific cancer deaths, overall mortality and the occurrence of metastatic spread. Meta-analyses were then conducted for different cancers and heterogeneity and publication bias assessed. Sensitivity analyses and attempts to reduce heterogeneity were conducted.

RESULTS

Analyses of 29 studies reported since an earlier review up to April 2015 are presented in this report, and these are then pooled with the 42 studies in our earlier publication. Overall meta-analyses of the 71 studies are presented, based on a total of over 120 thousand patients taking aspirin. Ten of the studies also give evidence on the incidence of metastatic cancer spread. There are now twenty-nine observational studies describing colorectal cancer (CRC) and post-diagnostic aspirin. Pooling the estimates of reduction by aspirin which are reported as hazard ratios (HR), gives an overall HR for aspirin and CRC mortality 0.72 (95% CI 0.64-0.80). Fourteen observational studies have reported on aspirin and breast cancer mortality and pooling those that report the association with aspirin as a hazard ratio gives HR 0.69 (0.53-0.90). Sixteen studies report on aspirin and prostate cancer mortality and a pooled estimate yields an HR of 0.87 (95% CI 0.73-1.05). Data from 12 reports relating to other cancers are also listed. Ten studies give evidence of a reduction in metastatic spread; four give a pooled HR 0.31 (95% CI 0.18, 0.54) and five studies which reported odds ratio of metastatic spread give OR 0.79 (0.66 to 0.95).

CONCLUSION

Being almost entirely from observational studies, the evidence of benefit from aspirin is limited. There is heterogeneity between studies and the results are subject to important biases, only some of which can be identified. Nevertheless, the evidence would seem to merit wide discussion regarding whether or not it is adequate to justify the recommendation of low-dose therapeutic aspirin, and if it is, for which cancers?

Nonsteroidal Anti-inflammatory Drugs and Clinical Outcomes among Men with Prostate Cancer: A Systematic Review and Meta-analysis

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown properties of inhibiting the progression of prostate cancer (PCa) in preclinical studies. However, epidemiological studies yield mixed results on the effectiveness of NSAIDs in PCa. Objective: The objective of this study was to determine the effect of NSAID use on clinical outcomes in PCa using systematic review and meta-analysis. Methods: Original articles published until the 1st week of October, 2016, were searched in electronic databases (Medline-Ovid, PubMed, Scopus, The Cochrane Library, and Web of Science) for studies on NSAID use in PCa. The main clinical outcomes for the review were: PCa-specific (PCM) and all-cause mortality (ACM), biochemical recurrence (BCR), and metastases. Meta-analysis was performed to calculate the pooled hazard ratio (pHR) and their 95% confidence interval (95% CI). Heterogeneity between the studies was examined using I2 statistics. Appropriate subgroup analyses were conducted to explore the reasons for heterogeneity. Results: Out of 4216 retrieved citations, 24 observational studies and two randomized controlled studies with a total of 89,436 men with PCa met the inclusion criteria. Overall, any NSAID use was not associated with PCM, ACM, and BCR, with significant heterogeneity. Neither precancer treatment aspirin use (pHR: 1.00, 95% CI: 0.83, 1.19, P = 0.97, 5 studies, I2: 51%) nor postcancer treatment aspirin use (pHR: 0.94, 95% CI: 0.72, 1.23, P = 0.67, 8 studies, I2: 86%) was associated with PCM. Similar findings, that is, no significant association was observed for NSAID use and ACM or BCR overall, and in subgroup by types of NSAID use, and NSAID use following radiation or surgery. Conclusion: Although NSAID use was not associated with ACM, PCM, or BCR among men with PCa, significant heterogeneity remained in the included studies even after subgroup analyses.

Analysis of Tumor Biology to Advance Cancer Health Disparity Research

Cancer mortality rates in the United States continue to decline. Reductions in tobacco use, uptake of preventive measures, adoption of early detection methods, and better treatments have resulted in improved cancer outcomes for men and women. Despite this progress, some population groups continue to experience an excessive cancer burden when compared with other population groups. One of the most prominent cancer health disparities exists in prostate cancer. Prostate cancer mortality rates are highest among men of African ancestry when compared with other men, both in the United States and globally. This disparity and other cancer health disparities are largely explained by differences in access to health care, diet, lifestyle, cultural barriers, and disparate exposures to carcinogens and pathogens. Dietary and lifestyle factors, pathogens, and ancestry-related factors can modify tumor biology and induce a more aggressive disease. There are numerous examples of how environmental exposures, like tobacco, chronic stress, or dietary factors, induce an adverse tumor biology, leading to a more aggressive disease and decreased patient survival. Because of population differences in the exposure to these risk factors, they can be the cause of cancer disparities. In this review, we will summarize recent advances in our understanding of prostate and breast cancer disparities in the United States and discuss how the analysis of tumor biology can advance health disparity research.

Aspirin Use Reduces the Risk of Aggressive Prostate Cancer and Disease Recurrence in African-American Men

Background: Men of African descent experience a disproportionately high prostate cancer mortality. Intratumoral inflammation was found to be associated with aggressive prostate cancer. We and others have shown that prostate tumors in African-American (AA) patients harbor a distinct immune and inflammation signature when compared with European-American (EA) patients. These observations suggest that inflammation could be a driver of aggressive disease in men of African descent, leading to the hypothesis that an anti-inflammatory drug like aspirin could prevent disease progression.Methods: We examined the relationship between aspirin use and prostate cancer in the NCI-Maryland Prostate Cancer Case-Control Study consisting of 823 men with incident prostate cancer (422 AA and 401 EA) and 1,034 population-based men without the disease diagnosis (486 AA and 548 EA).Results: We observed a significant inverse association between regular aspirin use and prostate cancer among AA men. Stratification of AA patients by disease stage showed that daily and long-term (>3 years) aspirin use significantly decreased the risk of advanced disease [adjusted ORs for T3/T4 disease: 0.35, 95% confidence interval (CI), 0.17-0.73; and 0.22, 95% CI, 0.08-0.60, respectively], but not early-stage disease (T1/T2). Regular aspirin use also reduced disease recurrence in AA men.Conclusions: Regular aspirin use is associated with a decreased risk of advanced stage prostate cancer and increased disease-free survival in AA men.Impact: Regular aspirin use before and after a prostate cancer diagnosis may prevent the development of aggressive disease in AA men who are at risk of a lethal malignancy. Cancer Epidemiol Biomarkers Prev; 26(6); 845-53. ©2017 AACR.

Do Aspirin and Other NSAIDs Confer a Survival Benefit in Men Diagnosed with Prostate Cancer? A Pooled Analysis of NIH-AARP and PLCO Cohorts

Prostate cancer is one of the leading causes of cancer-related death in U.S. men. There is an unmet need to identify modifiable risk factors for prostate cancer survival. Experimental studies have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) may improve prostate cancer survival through antithrombotic and anti-inflammation mechanisms. Results from previous observational studies have been equivocal, and few have assessed whether an etiologically relevant time window of exposure exists. We sampled incident prostate cancer cases from two large U.S. prospective cohorts, NIH-AARP Diet and Health Study and PLCO Cancer Screening Trial, to investigate whether pre- and postdiagnostic aspirin and non-aspirin NSAID use were associated with prostate cancer-specific and all-cause mortality. Cox proportional hazards regression models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Study-specific results were meta-analyzed using fixed-effects models. Pre- and postdiagnostic aspirin or non-aspirin NSAID use were not statistically significantly associated with prostate cancer-specific mortality. However, occasional (less than daily) and daily aspirin users five years or more before prostate cancer diagnosis had 18% (HR = 0.82; 95% CI = 0.75-0.90) and 15% (HR = 0.85; 95% CI = 0.77-0.94) reduced all-cause mortality versus nonusers. Similarly, postdiagnostic occasional and daily aspirin use were associated with 17% (HR = 0.83; 95% CI=0.72-0.95) and 25% (HR = 0.75; 95% CI = 0.66-0.86) reduced all-cause mortality, independent of prediagnostic aspirin use. This study suggests that aspirin or non-aspirin NSAIDs are not associated with prostate cancer survival. However, aspirin use both before and after prostate cancer diagnosis was associated with longer overall survival, highlighting the importance of comorbidity prevention among prostate cancer survivors. Cancer Prev Res; 10(7); 410-20. ©2017 AACR.

Aspirin inhibits the proliferation and migration of gastric cancer cells in p53-knockout mice

The aim of the present study was to investigate the effect of aspirin on the cell proliferation and migration of gastric cancer cells in p53-knockout mice. Twenty p53^−/− male mice aged 6 to 7 weeks, with an average weight of 20±3 g were used. The model of gastric cancer was established by the implantation of a mouse forestomach carcinoma cell line, subcutaneously, at the back of the neck, and then the mice were randomly divided into two groups after establishment of the model (control group, n=10; experimental group, n=10). Aspirin (250 mg/kg) was added to the food in the experimental group one day before model establishment, until the end of the experiment. Mice in the control group were given regular food without aspirin. All mice were sacrificed 3 months afterwards, and gastric cancer tissues were harvested. MTT assay was used to detect the proliferation of the tumor cells. Tumor cell number was also observed. Migration ability was detected by scratch assay, and E-cadherin protein expression was evaluated by immunofluorescence. The results revealed that the proliferation ability of tumor cells in the experimental group was lower than that in the control group. In addition, cell numbers were significantly decreased and the migration ability was diminished. The expression of E-cadherin was also increased in the experimental group, and the differences were statistically significant (P<0.05). In conclusion, aspirin inhibited the cell proliferation and migration of gastric cancer cells in mice.