Antihypertensive therapy and cancer risk

Antihypertensive drugs and the risks of cancer: More fakes than facts

In the last century, the diffusion of medical news to the public has been profoundly changed by the progressive spread of more pervasive, but at the same time often unreliable, means of communication. The misinterpretation of scientific evidence or fallacious presentation through social media could play as a great drawback to the success in the management of many diseases. This may become particularly alarming when concerning chronic diseases widely affecting the population. Arterial hypertension is still today one of the major causes of mortality and morbidity in most countries, and its management generally requires chronic therapy lasting for decades. Therefore, a recent debate about the potential oncogenic effect of antihypertensive drugs has been made widely available to patients mostly through social media. Since this is a topic of great impact for millions of patients and of main relevance for the scientific community, it must not be contaminated by the spread of fake or twisted news. The objective of this article is to briefly discuss the almost complete lack of hard evidence about the potential oncogenic effect of the major classes of antihypertensive drugs as opposed to the exaggerated mediatic communication and impact of scattered and unconfirmed observations. We believe that it is of key importance to provide authoritative support for patients and clinicians from scientific societies and guidelines to balance an unopposed widespread penetration of twisted or even fake news.

Antihypertensive drugs and the risk of cancer: a critical review of available evidence and perspective

: The issue of a potential danger of antihypertensive drugs related to cancer susceptibility is currently generating a major debate in the scientific community, concerns in the public and emphasized interest from the media. The present article is a thorough review of what is known on the various classes of antihypertensive drugs concerning the risk of developing different neoplasms and about the suggested pathophysiological mechanisms, whenever available. The main limitations of evidence derived from studies currently available in this setting are also discussed, high-lightening the need for newly developed approaches to generate more accurate recommendations and informed advice for physicians.

Antihypertensive Drugs and the Risk of Cancer: A Nationwide Cohort Study

We sought to assess the association between common antihypertensive drugs and the risk of incident cancer in treated hypertensive patients. Using the Korean National Health Insurance Service database, the risk of cancer incidence was analyzed in patients with hypertension who were initially free of cancer and used the following antihypertensive drug classes: Angiotensin-converting enzyme inhibitors (ACEIs); angiotensin receptor blockers (ARBs); beta blockers (BBs); calcium channel blockers (CCBs); and diuretics. During a median follow-up of 8.6 years, there were 4513 (6.4%) overall cancer incidences from an initial 70,549 individuals taking antihypertensive drugs. ARB use was associated with a decreased risk for overall cancer in a crude model (hazard ratio (HR): 0.744, 95% confidence interval (CI): 0.696-0.794) and a fully adjusted model (HR: 0.833, 95% CI: 0.775-0.896) compared with individuals not taking ARBs. Other antihypertensive drugs, including ACEIs, CCBs, BBs, and diuretics, did not show significant associations with incident cancer overall. The long-term use of ARBs was significantly associated with a reduced risk of incident cancer over time. The users of common antihypertensive medications were not associated with an increased risk of cancer overall compared to users of other classes of antihypertensive drugs. ARB use was independently associated with a decreased risk of cancer overall compared to other antihypertensive drugs.

Antihypertensive agents and the risk of breast cancer in women aged 55 years and older: a nested case-control study

OBJECTIVE

The study aimed to investigate the association of long-term use of different antihypertensive agents with incident breast cancer.

METHODS

A total of 794 ,533 women aged at least 55 years were identified from Taiwan National Health Insurance claims database during 2001-2011. As of 31 December 2011, incident breast cancer patients were included as cases, and 1 : 4 age-matched controls were selected by risk-set sampling scheme. Logistic regression models were applied to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer incidence associated with different durations of use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dihydropyridine calcium channel blockers (DHP CCBs). Different restriction rules were applied to reveal the potential effects of confounding by indication.

RESULTS

Among the 9397 incident breast cancer patients and 37 ,588 controls, a significantly elevated risk was found for relatively short-term use of DHP CCBs (<6 years) but not in those observed for more than 6 years. There was no association between either angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or β-blockers use and breast cancer. Although restricting our analyses to those with any prescription of antihypertensive medications in 2001 or those with diagnosis of hypertension, there was no longer a statistically significant association between any use of DHP CCBs and breast cancer (OR: 1.21, 95% CI: 0.88-1.67 for the former, and OR: 1.71, 95% CI: 0.99-2.95 for the latter).

CONCLUSION

The results demonstrated the potential effect of confounding by indication, and thus, did not suggest any association of the use of antihypertensive medication and breast cancer risk.

[Advance in Research of Angiotensin II and Its Receptor and Malignant Tumor]

Angiotensin AngII, a linear small peptide,which is composed of eight amino acids, is the main effectors of renin-angiotensin systen (Renin-angiotensin system, RAS). AngII, a main biopolypeptide of the RAS, has important pathophysiologic in effects participating in cardiac hypertrophy, vascular cell proproliferation, inflammation and tissue remodeling through G-protein-coupled receptors. In recent years, Ang II can promote tumor cell proliferation, tumor vessel formation and inhibit the differentiation of the tumor cells. This suggests that inhibit the production of AngII or block its effect is expected to become a new measure for the treatment of malignant tumors. This article reviews the advances in research on the relationship between AngII and its receptor and malignant tumor in recent years.

A review of clinical studies on angiotensin II receptor blockers and risk of cancer

Angiotensin II receptor blockers (ARBs) are one of the most frequently used antihypertensive drugs with good tolerability and are indicated for treatment of many cardiovascular morbidity. Findings from clinical studies conducted in the past decade, suggest a possible relationship between some ARB-active substances, and certain malignancies cannot be excluded. Despite a lack of agreement, clinical results do not rule out the possibility that type 2 angiotensin II receptor stimulation during ARB therapy may also have unfavorable consequences, such as the development of certain malignancies. However, according to the current official position of FDA, the cardiovascular benefits of ARB therapy far outweigh the risks. Based on the limited information available, this review aims to provide medical practitioners with a clearer view on the balance of the benefits and risks of ARBs.

An FDA overview of rodent carcinogenicity studies of angiotensin II AT-1 receptor blockers: pulmonary adenomas and carcinomas

Sipahi et al. (2010) performed a meta-analysis of 5 clinical trials (n=68,402) of 3 Angiotensin II (AngII) receptor subtype AT-1 blockers (ARBs) in cardiovascular disease. It revealed excess new lung cancer diagnoses in the cohorts treated with an ARB and background therapy (0.9% vs. 0.7% in non-ARB control; RR: 1.25; CI: 1.05-1.49; p=0.01). The FDA responded with a larger meta-analysis of 31 clinical trials (n=155,816) of ARBs that found no evidence of any excess of site-specific cancer (lung, breast, prostate), solid/skin cancer or cancer death (FDA safety communication, 3 June 2011). The FDA then re-visited the 19 rodent carcinogenicity assays of 9 ARBs, starting with those for Losartan in 1994, for any evidence of dosage-related lung tumorigenicity in this class. Assays were performed in 5 strains of rats and 5 strains of wild-type and transgenic mice per protocols and dosages sanctioned by FDA's executive carcinogenicity assessment committee (eCAC). Duration was lifetime except for 26-week assays of azilsartan and olmesartan in transgenic Tg rasH2 mice, and an assay of olmesartan in p53(+/-) transgenic mice. The dosages provided exposures approximating, and in most cases up to 20-300times greater than, that in patients. Depending on strain, up to 35% of untreated mice spontaneously developed lung tumors. Regression analysis of placebo-corrected mouse lung tumor incidence collapsed across strains, gender, and ARBs vs. multiples of human exposure revealed no excess lung neoplasia. The R(2) of <0.001 reflected the virtually identical number of treated cohorts with more tumors than its control cohort vs. those with less. Regardless of strain, both control and medicated rats were essentially devoid of lung tumors in the lifetime trials. Accordingly, there was neither promotion of background lung tumors in the mouse, nor initiation of de novo lung tumors in the rat. The negative lung findings in the mouse Tg rasH2 strain are also noteworthy given that, historically, the most prevalent spontaneous tumors in 26week trials in that model are lung adenomas and carcinomas. The negative results of the 19, mostly lifetime, assays for cancer viewed en masse add to the results of the meta-analysis of the shorter clinical trials of ARBs that were benign regardless of statistical method used (random vs. fixed effect), comparator arm (with or without ACE-inhibitors) and major co-factors (smoking or cancer history).

Commonly used diabetes and cardiovascular medications and cancer recurrence and cancer-specific mortality: a review of the literature

INTRODUCTION

Cancer most commonly arises in the elderly who are often burdened with comorbidities. Medications used for treating these comorbidities may alter cancer prognosis. Understanding the impact of these medications on cancer is important in order to make effective evidence-based decisions about managing comorbidities while improving cancer outcomes.

AREAS COVERED

The evidence on diabetes, statins, antihypertensive and anti-inflammatory medications and their association with cancer recurrence and cancer-specific mortality are reviewed. The strengths and limitations of the existing literature, the current state of the field and future directions are discussed.

EXPERT OPINION

Metformin and aspirin were associated with a reduced risk of cancer recurrence and cancer-specific mortality. The evidence for statins and antihypertensive medications on cancer survival was inconsistent. There were few studies to suggest that any of the medication classes of interest were associated with negative effects on cancer survival. Methodological shortcomings within observational studies, such as confounding, distinguishing between use of medications pre-cancer versus post-cancer diagnosis/treatment, misclassification of exposures/outcomes, informative censoring and competing risks, must be considered. New observational studies addressing these limitations are essential. Some clinical trials are underway to further investigate the beneficial effects of these drugs and completed trials have confirmed results demonstrated in observational studies.

Comparative safety of cardiovascular medication use and breast cancer outcomes among women with early stage breast cancer

Breast cancer tends to occur in an older age group of women also burdened with comorbidities such as cardiovascular disease (CVD). Numerous medications used to manage CVD (e.g., statins and antihypertensives) are hypothesized to alter breast cancer risk, but there are few studies on breast cancer outcomes. The COmmonly used Medications and Breast Cancer Outcomes (COMBO) cohort was developed to study how medications and co-morbidities influence breast cancer prognosis. Cohort study among adult women, diagnosed with incident early stage breast cancer, and enrolled in an integrated health plan. Data sources included health plan administrative databases, Surveillance, Epidemiology, and End Results tumor registry, and medical records. Statins, angiotensin-converting enzyme inhibitors (ACEI), beta blockers (BB), calcium blockers, and diuretics were the exposures of interest. The outcome was second breast cancer events (SBCE) defined as recurrence or second primary breast cancer. We used multivariable Cox proportional hazards models to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for SBCE, and components of SBCE. 4,216 women were followed for a median of 6.3 years, and 13.2 % experienced a SBCE (first of: n = 415 recurrences and n = 143 s primary breast cancers). Compared to non-users, we observed an increased risk of second primary breast cancer with ACEI use (HR = 1.66; 95 % CI, 1.06-2.58) and an increased risk of recurrence with BB use (HR = 1.29; 95 % CI, 1.01-1.64). There was suggestion of a reduced risk of SBCE with statin use (HR = 0.82; 95 % CI, 0.62-1.08) and second primary breast cancer with BB use (HR = 0.77; 95 % CI, 0.50-1.19). No differences in outcomes were observed by duration of medication use. A majority of CVD medications evaluated in this study appear safe with respect to SBCE, but ACEI and BB use warrant further evaluation. The study presented is one example of the questions that can be addressed using the COMBO cohort.

Metformin and the incidence of prostate cancer in patients with type 2 diabetes

BACKGROUND

Several in vitro studies have indicated that metformin may reduce the risk of prostate cancer; however, epidemiologic studies have been inconclusive. The objective of this study was to determine whether metformin decreases the risk of prostate cancer in patients with type 2 diabetes.

METHODS

A nested case-control analysis was conducted within a population-based cohort from the UK General Practice Research Database. The cohort included patients over the age of 40 who were prescribed a first oral hypoglycemic agent (OHA) between 1988 and 2009. Cases of prostate cancer were matched up to ten controls on year of birth, date of cohort entry, and duration of follow-up. Adjusted rate ratios (RR) were estimated using conditional logistic regression.

RESULTS

The cohort included 63,049 incident users of OHAs, in which 739 cases of prostate cancer were matched to 7,359 controls. Metformin use did not decrease the risk of prostate cancer (RR: 1.23, 95% CI: 0.99-1.52). In secondary analyses, prostate cancer risk was found to increase as a function of the number of metformin prescriptions received (one to seven prescriptions: RR: 1.05, 95% CI: 0.80-1.37; seven to eighteen prescriptions: RR: 1.29, 95% CI: 0.99-1.69; eighteen to thirty-six prescriptions: RR: 1.37, 95% CI: 1.04-1.81; more than thirty-six prescriptions: RR: 1.40, 95% CI: 1.03-1.89).

CONCLUSION

The results of this study indicate that metformin does not reduce the risk of prostate cancer in patients with type 2 diabetes.

IMPACT

The secondary analyses need to be interpreted with caution given the inverse association between type 2 diabetes and prostate cancer.

Antidepressants and risk of prostate cancer: a nested case – control study

Although the association between antidepressant drug use and risk of cancer has received considerable attention in the past years, no work has been done specifically on prostate cancer. We carried out a population-based case-control study to assess the risk of prostate cancer in association with exposure to tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). 7767 prostate cancer cases diagnosed between 1981 and 2000 were accrued through the Saskatchewan Cancer Agency. Saskatchewan Health identified a total of 31,068 male controls who were matched on age and calendar time. Data on exposure to TCAs and SSRIs were compiled from the Saskatchewan outpatient prescription drug database, and covered a period upto 24 years. A positive significant association was found between TCA use and risk of prostate cancer, when exposure took place 2-5 years before diagnosis, with rate ratios of 1.31, 1.58, and 2.42 at the low, medium and high average daily dose levels, respectively. Exposure to SSRIs was not found to be significantly associated with the risk of prostate cancer. TCA use 2-5 years in the past was associated with a small dose-dependent increase in the risk of prostate cancer. Nevertheless, detection bias could have contributed to the observed association.

A cohort study of antihypertensive medication use and breast cancer among Danish women

BACKGROUND

It has been suggested that specific antihypertensive medications (AHT) may either increase or decrease breast cancer risk.

METHODS

We studied breast cancer incidence among 49,950 women in North Jutland, Denmark in order to determine if breast cancer risk is associated with specific classes of AHT use. Poisson regression analyses were used to calculate rate ratios for ever or exclusive use of each class of AHT, number of prescriptions for AHT, and years of follow-up.

RESULTS

There was no statistically significant association between ever use of any AHT overall (RR = 0.95; 95% CI = 0.81-1.10) or any specific class of AHT (diuretics, beta blockers, calcium channel blockers (CCBs), angiotensin converting enzyme (ACE) inhibitors, and angiotensin II antagonists) and breast cancer.

CONCLUSIONS

This study should offer further reassurance to women currently using AHT that their medication use is unlikely related to breast cancer risk.

Angiotensin-converting enzyme inhibitors side effects--physiologic and non-physiologic considerations

Angiotensin-converting enzyme (ACE) inhibitors are increasingly recognized as having an important role in the treatment of hypertension and/or end-organ disease. The sheer number of ACE inhibitors in the United States--now numbering 10 different chemical entities--has created a sense of comfort with these compounds, which is particularly evident when these compounds are used in the patient with essential hypertension; conversely, when comorbid conditions are present in the ACE inhibitor-treated patient, circumstances change and physician vigilance becomes more of a necessity. ACE inhibitor therapy in patients with either cardiac and/or renal disease is as much an art as it is a science, and even in the most skilled hands can prove a challenging undertaking. This review discusses the physiologic and non-physiologic basis for side effects with ACE inhibition.

Effect of Angiotensin-Converting Enzyme Inhibition on Survival in 3773 Chinese Type 2 Diabetic Patients

We assessed the effects of angiotensin-converting enzyme (ACE) inhibition on survival and cardiorenal outcomes in a consecutive cohort of Chinese type 2 diabetic patients with varying degree of albuminuria, ranging from normoalbuminuria to macroalbuminuria. A total of 3773 consecutive Chinese type 2 diabetic patients were followed prospectively for a mean period of 35.8 months. Clinical end points included all-cause mortality, with cardiovascular end point defined as first hospitalization because of ischemic heart disease, congestive heart failure, revascularization procedures, or cerebrovascular accident as well as renal end point defined as dialysis, doubling of baseline plasma creatinine, or plasma creatinine ≥500 μmol/L. The use of ACE inhibitor was 26.3% in normoalbuminuric (NA), 70.1% in microalbuminuric (MI), and 82.6% in macroalbuminuric (MA) groups. Albuminuria was a major predictor for all-cause mortality with 4-fold difference between NA and MA patients. The 7-year cumulative mortality rate was 7.1%, 10.8%, and 21.7% in the NA, MI, and MA groups, respectively. The use of ACE inhibition was associated with significant reduction of mortality (hazard ratio 0.41 and 95% confidence interval, 0.29, 0.58) in the entire group and was most evident in high-risk patients who had cardiorenal complications or retinopathy at baseline for all albuminuric groups (NA 0.76 [0.31,1.87]; MI 0.32 [0.16, 0.65]; and MA 0.20 [0.13, 0.33]). The prognostic value of albuminuria for death in type 2 diabetes and the beneficial effects of ACE inhibitors in Chinese type 2 diabetic patients with micro- or macroalbuminuria has been confirmed. The effects of ACE inhibitors in type 2 diabetic patients with normoalbuminuria require further evaluation.

[Could treatments with beta-blockers be associated with a reduction in cancer risk?]

BACKGROUND

The relationship between the use of anti-hypertensive drugs and cancer risk remains controversial. The main objective of this study was to assess the potential effect of beta-blocker use on cancer risk.

METHODS

In a cohort of 839 patients with cardiovascular disease, followed up prospectively for an average period of 10 years, cancer occurrence was recorded according to the exposure to beta-blockers. The relative risk of cancer associated with beta-blocker use was estimated using a Cox model adjusted on gender and age. Ever- vs never-use of beta-blockers and duration of exposure to the drug were analyzed as time-dependent variables. In addition, the standardized incidence ratios (SIR) were calculated using the corresponding age- and gender-adjusted cancer incidences in the French general population.

RESULTS

A total of 326 beta-blocker users and 513 users of other treatments were included in the cohort. During the follow-up period, representing 8,466 person-years, incident cancer cases were 15 and 59 in beta-blocker ever-users versus never-users, respectively. Using the Cox model, the overall relative risk of cancer was 0.51 (95% confidence interval [95% CI]: 0.29-0.90) in the beta-blocker ever-users versus never-users (p=0.02), with a 6% decrease per year of use (95% CI: 1%-12%; p=0.03). The corresponding SIR ratio between these two groups was 0.44 (95% CI: 0.24-0.76).

CONCLUSION

In this cohort, the beta-blocker treatments appeared to decrease the cancer risk significantly. However, this result should be considered with caution; further work is needed, as some sources of bias associated with this type of epidemiological study cannot be totally excluded.