The Effects of Tamoxifen on Plasma Lipoprotein(a) Concentrations: Systematic Review and Meta-Analysis

Recommendations of the Experts of the Polish Cardiac Society (PCS) and the Polish Lipid Association (PoLA) on the diagnosis and management of elevated lipoprotein(a) levels

Lipoprotein(a) [Lp(a)] is made up of a low-density lipoprotein (LDL) particle and a specific apolipoprotein(a). The blood concentration of Lp(a) is approximately 90% genetically determined, and the main genetic factor determining Lp(a) levels is the size of the apo(a) isoform, which is determined by the number of KIV2 domain repeats. The size of the apo(a) isoform is inversely proportional to the blood concentration of Lp(a). Lp(a) is a strong and independent cardiovascular risk factor. Elevated Lp(a) levels ≥ 50 mg/dl (≥ 125 nmol/l) are estimated to occur in more than 1.5 billion people worldwide. However, determination of Lp(a) levels is performed far too rarely, including Poland, where, in fact, it is only since the 2021 guidelines of the Polish Lipid Association (PoLA) and five other scientific societies that Lp(a) measurements have begun to be performed. Determination of Lp(a) concentrations is not easy due to, among other things, the different sizes of the apo(a) isoforms; however, the currently available certified tests make it possible to distinguish between people with low and high cardiovascular risk with a high degree of precision. In 2022, the first guidelines for the management of patients with elevated lipoprotein(a) levels were published by the European Atherosclerosis Society (EAS) and the American Heart Association (AHA). The first Polish guidelines are the result of the work of experts from the two scientific societies and their aim is to provide clear, practical recommendations for the determination and management of elevated Lp(a) levels.

The benefits and risks of menopause hormone therapy for the cardiovascular system in postmenopausal women: a systematic review and meta-analysis

BACKGROUND

Menopause hormone therapy (MHT), as an effective method to alleviate the menopause-related symptoms of women, its benefits, risks, and potential influencing factors for the cardiovascular system of postmenopausal women are not very clear.

OBJECTIVES

To evaluate cardiovascular benefits and risks of MHT in postmenopausal women, and analyze the underlying factors that affect both.

SEARCH STRATEGY

The EMBASE, MEDLINE, and CENTRAL databases were searched from 1975 to July 2022.

SELECTION CRITERIA

Randomized Clinical Trials (RCTs) that met pre-specified inclusion criteria were included.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. A meta-analysis of random effects was used to analyze data.

MAIN RESULTS

This systematic review identified 33 RCTs using MHT involving 44,639 postmenopausal women with a mean age of 60.3 (range 48 to 72 years). There was no significant difference between MHT and placebo (or no treatment) in all-cause death (RR = 0.96, 95%CI 0.85 to 1.09, I2 = 14%) and cardiovascular events (RR = 0.97, 95%CI 0.82 to 1.14, I2 = 38%) in the overall population of postmenopausal women. However, MHT would increase the risk of stroke (RR = 1.23, 95%CI 1.08 to 1.41,I2 = 0%) and venous thromboembolism (RR = 1.86, 95%CI 1.39 to 2.50, I2 = 24%). Compared with placebo, MHT could improve flow-mediated arterial dilation (FMD) (SMD = 1.46, 95%CI 0.86 to 2.07, I2 = 90%), but it did not improve nitroglycerin-mediated arterial dilation (NMD) (SMD = 0.27, 95%CI - 0.08 to 0.62, I2 = 76%). Compared with women started MHT more than 10 years after menopause, women started MHT within 10 years after menopause had lower frequency of all-cause death (P = 0.02) and cardiovascular events (P = 0.002), and more significant improvement in FMD (P = 0.0003). Compared to mono-estrogen therapy, the combination therapy of estrogen and progesterone would not alter the outcomes of endpoint event. (all-cause death P = 0.52, cardiovascular events P = 0.90, stroke P = 0.85, venous thromboembolism P = 0.33, FMD P = 0.46, NMD P = 0.27).

CONCLUSIONS

MHT improves flow-mediated arterial dilation (FMD) but fails to lower the risk of all-cause death and cardiovascular events, and increases the risk of stroke and venous thrombosis in postmenopausal women. Early acceptance of MHT not only reduces the risk of all-cause death and cardiovascular events but also further improves FMD, although the risk of stroke and venous thrombosis is not reduced. There is no difference in the outcome of cardiovascular system endpoints between mono-estrogen therapy and combination therapy of estrogen and progesterone.

The ins and outs of lipoprotein(a) assay methods

Pathophysiological, epidemiological and genetic studies convincingly showed lipoprotein(a) (Lp(a)) to be a causal mediator of atherosclerotic cardiovascular disease (ASCVD). This happens through a myriad of mechanisms including activation of innate immune cells, endothelial cells as well as platelets. Although these certainties whether or not Lp(a) is ready for prime-time clinical use remain debated. Thus, remit of the present review is to provide an overview of different methods that have been employed for the measurement of Lp(a). The methods include dynamic light scattering, multi-angle light scattering analysis, near-field imaging, sedimentation, gel filtration, and electron microscopy. The development of multiple Lp(a) detection methods is vital for improved prediction of ASCVD risk.

The Cardiovascular Risks Associated with Aromatase Inhibitors, Tamoxifen, and GnRH Agonists in Women with Breast Cancer

PURPOSE OF REVIEW

Cardiovascular disease accounts for up to 10% of all-cause mortality in women with a diagnosis of breast cancer, and the causes for this are multifaceted. Many women at risk of or with a diagnosis of breast cancer are on endocrine-modulating therapies. It is therefore important to understand the effect of hormone therapies on cardiovascular outcomes in breast cancer patients to mitigate against any adverse effects and to identify those most at risk so that they can be proactively managed. Here we discuss the pathophysiology of these agents, their effect on the cardiovascular system, and the latest evidence on their cardiovascular risks association.

RECENT FINDINGS

Tamoxifen appears to be cardioprotective during treatment but not over the longer term, while the effect of AIs on cardiovascular outcomes remains controversial. Heart failure outcomes remain understudied, and the cardiovascular effects of gonadotrophin-releasing hormone agonists (GNRHa) in women need further research, especially since data from men with prostate cancer have indicated an increased risk of cardiac events in GNRHa users. There remains a need for a greater understanding of the effects of hormone therapies on cardiovascular outcomes in breast cancer patients. Further areas of research in this area include developing evidence to better define the optimal preventive and screening methods for cardiovascular effects and the risk factors for patients on hormonal therapies.

New Concepts in Cardio-Oncology

Cancer and cardiovascular disease are the two major causes of morbidity and mortality in worldwide. Discovering new therapeutic agents for the management of breast cancer (BC) has increased the numbers of cancer survivors but with the risk of cardiovascular adverse events (CV-AEs). All drugs can potentially damage the cardiovascular system, with different types of clinical manifestations from ischemic myocardial disease to vasculitis, thrombosis or pericarditis. An early detection of CV-AEs guarantees an earlier treatment, which is associated with better outcomes. Cardio-oncology field enlarged its studies to improve prevention, monitoring and treatment of all cardiotoxic manifestations related to old or modern oncological agents. A multidisciplinary approach with a close partnership between oncologists and cardiologists is essential for an optimal management and therapeutic decision-making. The aim of this chapter is to review all types of cardiotoxic manifestations related to novel and old agents approved for treatment of BC patients including chemotherapy, anti-HER2 agents, cyclin-dependent kinase 4/6 inhibitors, PolyADP-ribose polymerase (PARP) inhibitors, antiangiogenic drugs and immunotherapy. We also focused our discussion on prevention, monitoring, treatment, and management of CV-AEs.

Impact of anti-oestrogen therapy on lipoprotein(a) in postmenopausal women: a systematic review and meta-analysis of double-blind placebo-controlled clinical studies

PURPOSE

The potential mechanisms of endocrine therapy for thrombosis remain currently unclear, and more studies are warranted for further investigation and elucidation. However, high plasma concentration of lipoprotein(a) (Lp(a)) is a recognized prothrombotic factor. The aim of our study was to systematically evaluate the effect of different anti-oestrogen therapy on plasma Lp(a) level in postmenopausal women.

METHODS

A systematic literature search was conducted in multiple electronic databases to identify the randomized, double-blind, placebo-controlled clinical studies on this topic. Effect size for changes in Lp(a) was expressed as mean difference (MD) and 95% confidence intervals (CI).

RESULTS

Data were pooled from 10 clinical trials comprising 24 treatment arms, which included 2049 women (1128 women in the active-treated arms and 921 women in the control arms). Meta-analysis of data suggested that anti-oestrogen therapy in women significantly reduced Lp(a) [MD = -5.92% (95%CI: -9.05%,-2.8%)].

CONCLUSIONS

This observation is of both clinical and pathophysiological relevance, also in view that the identification of molecular determinants and cellular pathways implicated in Lp(a) synthesis and metabolism is still of concern as a critical issue in lipidology and CV prevention.

Cardio-oncology: Implications for Clinical Practice for Women

PURPOSE OF REVIEW

Clinical cardio-oncology considerations specific to women span across many areas and are particularly relevant for management of patients with sex-specific cancers, such as breast cancer.

RECENT FINDINGS

Major improvement in breast cancer survivorship over the last decade and the recognition of CV disease as the second leading cause of death among survivors point to the relevance of long-term cardiovascular (CV) safety. This review summarizes the CV effects associated with multimodality breast cancer treatments and contemporary approach to CV risk stratification, prevention, early detection, monitoring, and management at the time of cancer diagnosis, during and after completion of treatment. We highlight the growing role of a multidisciplinary, team-based approach for comprehensive CV and oncology care through the entire cancer treatment continuum, from diagnosis through survivorship.

The Effect of Bariatric Surgery on Circulating Levels of Lipoprotein (a): A Meta-analysis

Background

Obesity, especially severe obesity, is associated with a higher risk of atherosclerotic cardiovascular disease (ASCVD) morbidity and mortality. Bariatric surgery is a durable and effective weight loss therapy for patients with severe obesity and weight-related comorbidities. Elevated plasma levels of lipoprotein (a) (Lp(a)) are causally associated with ASCVD. The aim of this meta-analysis was to analyze whether bariatric surgery is associated with Lp(a) concentrations.

Methods

A literature search in PubMed, Scopus, Embase, and Web of Science was performed from inception to May 1st, 2021. A random-effects model and the generic inverse variance weighting method were used to compensate for the heterogeneity of studies in terms of study design, treatment duration, and the characteristics of the studied populations. A random-effects metaregression model was used to explore the association with an estimated effect size. Evaluation of funnel plot, Begg's rank correlation, and Egger's weighted regression tests were used to assess the presence of publication bias in the meta-analysis.

Results

Meta-analysis of 13 studies including 1551 patients showed a significant decrease of circulating Lp(a) after bariatric surgery (SMD: -0.438, 95% CI: -0.702, -0.174, p < 0.001, I²: 94.05%). The results of the metaregression did not indicate any significant association between the changes in Lp(a) and duration of follow-up after surgery, reduction in body mass index, or baseline Lp(a) concentration. The reduction in circulating Lp(a) was robust in the leave-one-out sensitivity analysis.

Conclusion

Bariatric surgery significantly decreases circulating Lp(a) concentrations. This decrease may have a positive effect on ASCVD in obese patients.

The effect of tamoxifen on the lipid profile in women: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The effect of tamoxifen administration on serum lipids in females remains unclear. The studies which have explored this topic have produced conflicting results, probably due to discrepancies in the length of the intervention, differences in baseline variables or other factors. To answer this research question, we decided to conduct this systematic review and meta-analysis to assess the effects of tamoxifen on the lipid profile in women.

METHODS

A comprehensive search was conducted in Web of Science, Scopus, PubMed/Medline and Embase, from the inception of these databases up to June 2021. We used a random effects meta-analysis to generate the combined results.

RESULTS

The overall findings were generated from 18 eligible trials. As compared to placebo, tamoxifen led to a notable reduction of the total cholesterol (TC) (WMD: -23.03 mg/dL, 95% CI: -25.94 to -20.12, P˂0.001), and the low-density lipoprotein-cholesterol (LDL-C) (WMD: -18.68 mg/dL, 95% CI: -24.31 to -13.04, P˂0.001). However, tamoxifen did not alter triglycerides (TG) concentrations (WMD: +1.06 mg/dL, 95% CI: -11.08 to 13.20, P = 0.864) significantly. A pronounced reduction of the high-density lipoprotein-cholesterol (HDLC) was noted in the RCTs with a duration of ≤52 weeks (WMD: -2.06 mg/dL) and when tamoxifen was administered in participants with a BMI ≥25 kg/m² (WMD: -1.42 mg/dL). Notable reductions in TC (WMD: -23.57 mg/dL) and LDL-C (WMD: -19.21 mg/dL) was detected when the dose of tamoxifen was ≥20 mg/day. Moreover, a significant reduction of TC (WMD: -20.23 mg/dL) and LDL-C (WMD: -24.13 mg/dL) was observed in the RCTs with a duration of ≤52 weeks.

CONCLUSION

Tamoxifen can alter the lipid profile in females, particularly by decreasing TC, LDL-C and HDLC. Tamoxifen can further reduce TC and LDL-C if the dose of administration is ≥20 mg/day, the treatment duration is ≤52 weeks and if it prescribed in subjects with dyslipidemia.

The Effects of Endocrine Therapies on Lipid Profiles in Chinese Young Women With Early Breast Cancer

This study aimed to evaluate and compare the effects of various endocrine therapies on lipid profiles in young patients with breast cancer. A retrospective, single-center study was performed to investigate the effects of tamoxifen (TAM), tamoxifen plus ovarian function suppression (TAM+OFS), and aromatase inhibitors plus ovarian function suppression (AI+OFS) on lipid profiles during the 60 months of endocrine therapy in hormone receptor-positive patients aged <40 with early breast cancer. The primary endpoint was the cumulative incidence of lipid events, and the secondary endpoints were the changes in lipid profiles. A total of 230 young patients were included with the mean age of 35.7 years old. The patients in TAM group had significantly lower incidence of 5-year lipid events than those in TAM+OFS group (7.4% versus 21.3%; P=0.016) and AI+OFS group (7.4% versus 21.6%; P=0.009). The incidence of fatty liver was significantly higher in TAM+OFS group than TAM group (52.5%versus 30.9%; P=0.043). Lipid events were associated with younger age (odds ratio (OR)=0.865, 95% confidence interval (CI): 0.780-0960; P=0.006), higher baseline LDL-C (OR=14.959, 95% CI: 4.379-51.105; P<0.001), and use of OFS (OR=3.557, 95% CI: 1.151-10.989; P=0.027). Therefore, application of OFS, with younger age and higher baseline LDL-C, may increase the incidence of lipid events in premenopausal breast cancer. More care should be taken for lipid profiles during the endocrine therapy for young breast cancer patients.

A preliminary study on the association of tamoxifen, endoxifen, and 4-hydroxytamoxifen with blood lipids in patients with breast cancer

The long-term treatment with tamoxifen can alter the lipid profile of patients with breast cancer. Only a few studies associated the plasma concentrations of tamoxifen, endoxifen, and 4-hydroxytamoxifen with blood lipids, which is relevant as the distribution of these compounds for the tissues can be changed, negatively affecting the treatment. The variations in lipids also can account for the high interindividual variation in plasma concentrations of these compounds. The aim of this preliminary study was to associate the plasma levels of tamoxifen and the active metabolites with the lipid levels. An observational study of cases was conducted in patients with breast cancer using tamoxifen in a daily dose of 20 mg. The lipids were measured by spectrophotometric methods and the plasma concentrations of tamoxifen, endoxifen, and 4-hydroxytamoxifen by high-performance liquid chromatography. A total of 20 patients were included in the study. The median plasma concentrations of tamoxifen, 4-hydroxytamoxifen and endoxifen were 62 ng/mL, 1.04 ng/mL and 8.79 ng/mL. Triglycerides levels ranged from 59 to 352 mg/dL, total cholesterol from 157 to 321 mg/dL, LDL-c from 72 mg/dL to 176 mg/dL and HDL-C from 25.1 mg/dL to 62.8 mg/dL. There were no significant associations between the plasma concentrations of tamoxifen, 4-hydroxytamoxifen, and endoxifen with the levels of triglycerides and total cholesterol. The multivariate analysis revealed a weak association between plasma concentrations of tamoxifen and the active metabolites with HDL-c, LDL-c and VLDL-c. This finding provides preliminary evidence of the low impact of lipoproteins levels in the exposure to tamoxifen, 4-hydroxytamoxifen and endoxifen.

Novel Therapeutical Approaches to Managing Atherosclerotic Risk

Atherosclerosis is a multifactorial vascular disease that leads to inflammation and stiffening of the arteries and decreases their elasticity due to the accumulation of calcium, small dense Low Density Lipoproteins (sdLDL), inflammatory cells, and fibrotic material. A review of studies pertaining to cardiometabolic risk factors, lipids alterations, hypolipidemic agents, nutraceuticals, hypoglycaemic drugs, atherosclerosis, endothelial dysfunction, and inflammation was performed. There are several therapeutic strategies including Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) inhibitors, inclisiran, bempedoic acid, Glucagon-Like Peptide-1 Receptor agonists (GLP-1 RAs), and nutraceuticals that promise improvement in the atheromatous plaque from a molecular point of view, because have actions on the exposure of the LDL-Receptor (LDL-R), on endothelial dysfunction, activation of macrophages, on lipid oxidation, formations on foam cells, and deposition extracellular lipids. Atheroma plaque reduction both as a result of LDL-Cholesterol (LDL-C) intensive lowering and reducing inflammation and other residual risk factors is an integral part of the management of atherosclerotic disease, and the use of valid therapeutic alternatives appear to be appealing avenues to solving the problem.

Cardiovascular toxicity of breast cancer treatment: an update

Novel chemotherapeutic agents have marked a new era in oncology during the past decade, prolonging significantly the overall survival of breast cancer patients. Nevertheless, contemporary antineoplastic treatments can frequently cause adverse cardiovascular side effects. Common manifestations of chemotherapy-induced cardiotoxicity include cardiomyopathy, ischemia, conduction disturbances, hypertension and thromboembolic events, while the type of the treatment regimen administered crucially determines clinical outcome. The aim of this literature review is to analyze the incidence and the underlying mechanisms of cardiovascular toxicity caused by agents approved for breast cancer, as well as to describe ways of monitoring and treating the cardiotoxic effects in breast cancer patients. Moreover, our work intends to provide an easy-to-grasp synopsis of recent and clinically meaningful advances in the field.

Increased cardiovascular risk associated with hyperlipoproteinemia (a) and the challenges of current and future therapeutic possibilities

Population, genetic, and clinical studies demonstrated a causative and continuous, from other plasma lipoproteins independent relationship between elevated plasma lipoprotein (a) [Lp(a)] concentration and the development of cardiovascular disease (CVD), mainly those related to athe-rosclerotic CVD, and calcific aortic stenosis. Currently, a strong international consensus is still lacking regarding the single value which would be commonly used to define hyperlipoproteinemia (a). Its prevalence in the general population is estimated to be in the range of 10%–35% in accordance with the most commonly used threshold levels (>30 or >50 mg/dL). Since elevated Lp(a) can be of special importance in patients with some genetic disorders, as well as in individuals with otherwise controlled major risk factors, the identification and establishment of the proper therapeutic interventions that would lower Lp(a) levels and lead to CVD risk reduction could be very important. The majority of the classical lipid-lowering agents (statins, ezetimibe, and fibrates), as well as nutraceuticals (CoQ10 and garlic), appear to have no significant effect on its plasma levels, whereas for the drugs with the demonstrated Lp(a)-lowering effects (aspirin, niacin, and estrogens), their clinical efficacy in reducing cardiovascular (CV) events has not been unequivocally proven yet. Both Lp(a) apheresis and proprotein convertase subtilisin/kexin type 9 inhibitors can reduce the plasma Lp(a) by approximately 20%–30% on average, in parallel with much larger reduction of low-density lipoprotein cholesterol (up to 70%), what puts us in a difficulty to conclude about the true contribution of lowered Lp(a) to the reduction of CV events. The most recent advancement in the field is the introduction of the novel apolipoprotein (a) [apo(a)] antisense oligonucleotide therapy targeting apo(a), which has already proven itself as being very effective in decreasing plasma Lp(a) (by even >90%), but should be further tested in clinical trials. The aim of this review was to present some of the most important accessible scientific data, as well as dilemmas related to the currently and potentially in the near future more widely available therapeutic options for the management of hyperlipoproteinemia (a).

Cumulative incidence of cardiovascular events under tamoxifen and letrozole alone and in sequence: a report from the BIG 1-98 trial

BACKGROUND

Compared to tamoxifen, adjuvant treatment with aromatase inhibitors improves disease outcomes of postmenopausal women with hormone receptor-positive early breast cancer. In the international, randomized, double-blind BIG 1-98 trial, 8010 women were randomized to receive tamoxifen, letrozole, or sequential use of the agents for 5 years. With a focus on switching between agents, we investigated cardiovascular events over the entire 5-year treatment period.

METHODS

Of the 6182 patients enrolled, 6144 started trial treatment and were included in this analysis. Adverse events occurring during study treatment until 30 days after cessation were considered. Eight cardiovascular event types were defined. Cumulative incidence of events were estimated using the Kaplan-Meier method, without consideration for competing events. Multivariable Cox models estimated hazard ratios (HR) with 95% confidence intervals (CI) for pairwise comparisons of treatment arms.

RESULTS

While on study treatment, 6.5% of patients (n = 397) had any cardiac events reported; for 2.4%, the event was grades 3-5, of which 11 (0.2%) were grade 5. Letrozole monotherapy was associated with higher risk of grade 1-5 ischemic heart disease (HR = 1.81; 95% CI, 1.06-3.08) compared with tamoxifen monotherapy. Patients assigned sequential tamoxifen →letrozole (HR = 1.59; 95% CI, 0.92-2.74) or sequential letrozole → tamoxifen (HR = 1.20; 95% CI, 0.68-2.14) showed a lesser degree of risk elevation. Patients assigned to tamoxifen-containing regimens had significantly higher risk of grade 1-5 thromboembolic events (tamoxifen monotherapy HR = 2.10; 95% CI, 1.42-3.12; tamoxifen → letrozole HR = 1.96; 95% CI, 1.32-2.92; letrozole → tamoxifen HR = 1.56; 95% CI 1.03-2.35) as compared with patients assigned letrozole alone.

CONCLUSION

When initiating or switching between adjuvant endocrine treatments in postmenopausal patients, age and medical history, with special attention to prior cardiovascular events, should be balanced with expected benefit of the treatment.

Dynamic Changes of Blood Lipids in Breast Cancer Patients After (Neo)adjuvant Chemotherapy: A Retrospective Observational Study

Background

Previous studies indicated that the (neo)adjuvant chemotherapy for breast cancer can cause significant dyslipidemia in patients, but how long this abnormality can persist is unclear so far. The purpose of this study is to investigate whether (neo)adjuvant chemotherapy has a long-term effect on blood lipids in breast cancer patients.

Methods

A total of 159 newly diagnosed female breast cancer patients receiving the (neo)adjuvant chemotherapy subsequently and 159 female healthy controls were enrolled into the observational study. All participants' blood lipid profiles which included TC, TG, HDL-C, and LDL-C before and at the end of the 1st and 12th month after chemotherapy were retrieved from the electronic medical record system. The blood lipid profiles and the percentage of dyslipidemia before and after chemotherapy in breast cancer patients and controls were compared.

Results

Compared with the baseline before chemotherapy, TC, LDL-C, and TG increased significantly at the end of the 1st month after chemotherapy, but only the abnormal increase in TG (2.98±0.71 mmol/L vs 2.82±0.63 mmol/L, P<0.05) and LDL-C (1.82±0.42 mmol/L vs 1.59±0.42 mmol/L, P<0.05) continued until the 12th month after chemotherapy. Levels of HDL-C in breast cancer patients and all the blood lipid parameters in controls remained stable during the observation period. The percentage of dyslipidemia in breast cancer patients rose from 41.5% at baseline to 54.1% at the 12th month after chemotherapy. Subgroup analysis demonstrated that the increase in dyslipidemia percentage was more pronounced in patients with low body mass index and aged over 50 years.

Conclusion

The (neo)adjuvant chemotherapy used for treating breast cancers can cause significant abnormalities in blood lipid profiles, and the abnormal increase in LDL-C and TG can last at least 12 months after chemotherapy, which indicates long-term management of blood lipid is necessary for those patients.

Hyperlipoproteinemia (a) is associated with breast cancer in a Han Chinese population

To investigate the relationship between serum lipoprotein (a) (LP(a)) levels and breast cancer as well as the clinicopathologic characteristics of breast cancer in a Han Chinese population.This study included 314 breast cancer patients, 51 patients with benign breast tumors, and 185 healthy control subjects. All study subjects were Han Chinese with similar socio-economic backgrounds, who were local residents of Zhoushan, Zhejiang, China or who had lived in Zhoushan for a long period of time. Serum concentrations of LP(a) were determined using a latex-enhanced immunoturbidimetric assay. Clinicopathological characteristics of patients were retrieved from medical records, which included the histopathological type, grade, stage, and molecular subtype of the disease, the expression of estrogen receptor (ER), progesterone receptor (PR), HER2, and Ki67, and the level of reproductive hormones. Correlations between 2 groups were evaluated using the Spearman correlation analysis. Associations among ≥3 groups were interpreted using the Kruskal-Wallis H test or the logistic regression test.Elevated serum LP(a) levels were detected in breast cancer patients compared with healthy control subjects, but no significant differences in LP(a) were detected between breast cancer and benign tumor or between benign tumor and healthy control. In breast cancer patients, serum LP(a) levels were inversely associated with HER2 expression, but they were not significantly correlated with any other clinicopathologic characteristics of breast cancer evaluated in this study.Elevated serum LP(a) levels were associated with breast cancer in a Han Chinese population.

Aromatase Inhibitors and the Risk of Cardiovascular Outcomes in Women With Breast Cancer: A Population-Based Cohort Study

BACKGROUND

The association between aromatase inhibitors and cardiovascular outcomes among women with breast cancer is controversial. Given the discrepant findings from randomized controlled trials and observational studies, additional studies are needed to address this safety concern.

METHODS

We conducted a population-based cohort study using the UK Clinical Practice Research Datalink linked to the Hospital Episode Statistics and Office for National Statistics databases. The study population consisted of women newly diagnosed with breast cancer initiating hormonal therapy with aromatase inhibitors or tamoxifen between April 1, 1998, and February 29, 2016. We usedCox proportional hazards models with inverse probability of treatment and censoring weighting to estimate hazard ratios (HRs) with 95% CIs comparing new users of aromatase inhibitors with new users of tamoxifen for each of the study outcomes (myocardial infarction, ischemic stroke, heart failure, and cardiovascular mortality).

RESULTS

The study population consisted of 23 525 patients newly diagnosed with breast cancer, of whom 17 922 initiated treatment with either an aromatase inhibitor or tamoxifen (8139 and 9783, respectively). The use of aromatase inhibitors was associated with a significantly increased risk of heart failure (incidence rate, 5.4 versus 1.8 per 1000 person-years; HR, 1.86 [95% CI, 1.14-3.03]) and cardiovascular mortality (incidence rate, 9.5 versus 4.7 per 1000 person-years; HR, 1.50 [95% CI, 1.11-2.04]) compared with the use of tamoxifen. Aromatase inhibitors were associated with elevated HRs, but with CIs including the null value, for myocardial infarction (incidence rate, 3.9 versus 1.8 per 1000 person-years; HR, 1.37 [95% CI, 0.88-2.13]) and ischemic stroke (incidence rate, 5.6 versus 3.2 per 1000 person-years; HR, 1.19 [95% CI, 0.82-1.72]).

CONCLUSIONS

In this population-based study, aromatase inhibitors were associated with increased risks of heart failure and cardiovascular mortality compared with tamoxifen. There were also trends toward increased risks, although nonsignificant, of myocardial infarction and ischemic stroke. The increased risk of cardiovascular events associated with aromatase inhibitors should be balanced with their favorable clinical benefits compared with tamoxifen.

Molecular, Population, and Clinical Aspects of Lipoprotein(a): A Bridge Too Far?

There is now significant evidence to support an independent causal role for lipoprotein(a) (Lp(a)) as a risk factor for atherosclerotic cardiovascular disease. Plasma Lp(a) concentrations are predominantly determined by genetic factors. However, research into Lp(a) has been hampered by incomplete understanding of its metabolism and proatherogeneic properties and by a lack of suitable animal models. Furthermore, a lack of standardized assays to measure Lp(a) and no universal consensus on optimal plasma levels remain significant obstacles. In addition, there are currently no approved specific therapies that target and lower elevated plasma Lp(a), although there are recent but limited clinical outcome data suggesting benefits of such reduction. Despite this, international guidelines now recognize elevated Lp(a) as a risk enhancing factor for risk reclassification. This review summarises the current literature on Lp(a), including its discovery and recognition as an atherosclerotic cardiovascular disease risk factor, attempts to standardise analytical measurement, interpopulation studies, and emerging therapies for lowering elevated Lp(a) levels.

Therapeutic management of hyperlipoproteinemia (a)

Cardiovascular disease (CVD) has consistently been the leading cause of death worldwide. Several clinical and epidemiological studies have demonstrated that an elevated plasma concentration of lipoprotein (a) [Lp(a)] is a causative and independent major risk factor for the development of CVD, as well as calcific aortic valve stenosis. Thus, the therapeutic management of hyperlipoproteinemia (a) has received much attention, as significant reductions in Lp(a) levels may, potentially, favorably affect cardiovascular risk. Aspirin, niacin, estrogens, and statins, which act on different molecular pathways, may be prescribed to patients with mild or modest elevations of Lp(a) levels. Other therapeutic interventions, such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, Lp(a) apheresis, and the novel antisense oligonucleotides APO(a)-Rx and APO(a)-LRx, which are being evaluated in ongoing clinical trials, have provided some promising results and can potentially be used in severe cases of hyperlipoproteinemia (a). This review aims to present and discuss the current clinical and scientific data pertaining to the therapeutic options for the management of hyperlipoproteinemia (a).

Cardiometabolic Effects of Endocrine Treatment of Estrogen Receptor-Positive Early Breast Cancer

Estrogen receptor-positive early breast cancer is common and has a relatively good prognosis. It shares risk factors with cardiovascular disease, and cardiovascular disease is an important competing cause of mortality. Adjuvant endocrine therapy with aromatase inhibitors (requiring concomitant ovarian suppression in premenopausal women) or selective estrogen receptor modulators (usually tamoxifen) exert oncologic benefits by respectively inhibiting estradiol synthesis or breast estrogen receptor signaling. Aromatase inhibitors cause systemic estradiol depletion. Tamoxifen has mixed agonistic/antagonistic effects in a tissue-dependent fashion. Given that estrogens modulate cardiometabolic risk, a review of the effects of endocrine therapy on cardiometabolic outcomes is pertinent. The current, but limited, evidence suggests that tamoxifen treatment, although associated with increases in body fat, hepatic steatosis, serum triglycerides, and diabetes risk, modestly reduces low-density lipoprotein cholesterol and lipoprotein(a) and may have favorable effects on markers of subclinical atherosclerosis. Tamoxifen is associated with either no effect on, or a reduction in, cardiovascular events, and it is associated with an increase in venous thromboembolic events. Aromatase inhibitors, although fewer studies are available and often confounded by comparison with tamoxifen, have not been consistently associated with adverse changes in cardiometabolic risk factors or increases in cardiovascular events. Further clinical trials designed to evaluate cardiometabolic outcomes are needed to more accurately determine the effects of endocrine therapy on cardiovascular risks, to inform individualized decisions regarding choice and duration of endocrine therapy, and to implement evidence-based strategies to mitigate cardiometabolic risks. In the meantime, although breast cancer-specific evidence for benefit of lifestyle measures is available and recommended routinely, proactive monitoring and treatment of cardiovascular risk factors should follow general population recommendations.

Impact of ezetimibe on plasma lipoprotein(a) concentrations as monotherapy or in combination with statins: a systematic review and meta-analysis of randomized controlled trials

The aim of this meta-analysis of randomized placebo-controlled clinical trials was to assess the effect of ezetimibe on plasma lipoprotein(a) concentrations. Only randomized placebo-controlled trials investigating the impact of ezetimibe treatment on cholesterol lowering that include lipoprotein(a) measurement were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to February 26th, 2018). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipoprotein concentrations. This meta-analysis of data from 10 randomized placebo-controlled clinical trials (15 treatment arms) involving a total of 5188 (3020 ezetimibe and 2168 control) subjects showed that ezetimibe therapy had no effect on altering plasma Lp(a) concentrations (WMD: -2.59%, 95% CI: -8.26, 3.08, p = 0.370; I2 = 88.71%, p(Q) < 0.001). In the subgroup analysis, no significant alteration in plasma Lp(a) levels was observed either in trials assessing the impact of monotherapy with ezetimibe versus placebo (WMD: -4.64%, 95% CI: -11.53, 2.25, p = 0.187; I2 = 65.38%, p(Q) = 0.005) or in trials evaluating the impact of adding ezetimibe to a statin versus statin therapy alone (WMD: -1.04%, 95% CI: -6.34, 4.26, p = 0.700; I2 = 58.51%, p(Q) = 0.025). The results of this meta-analysis suggest that ezetimibe treatment either alone or in combination with a statin does not affect plasma lipoprotein(a) levels.

Effect of soy isoflavone supplementation on plasma lipoprotein(a) concentrations: A meta-analysis

BACKGROUND

Soy supplementation has been shown to reduce total and low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol. However, contradictory effects of soy isoflavone supplementation on lipoprotein(a) [Lp(a)] have been reported suggesting the need for a meta-analysis to be undertaken.

OBJECTIVE

The aim of the study was to investigate the impact of supplementation with soy isoflavones on plasma Lp(a) levels through a systematic review and meta-analysis of eligible randomized placebo-controlled trials.

METHODS

The search included PubMed-Medline, Scopus, ISI Web of Knowledge, and Google Scholar databases (by March 26, 2017), and quality of studies was evaluated according to Cochrane criteria. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analysis were performed to assess the modifiers of treatment response.

RESULTS

Ten eligible studies comprising 11 treatment arms with 973 subjects were selected for the meta-analysis. Meta-analysis did not suggest any significant alteration of plasma Lp(a) levels after supplementation with soy isoflavones (standardized mean difference: 0.08, 95% confidence interval: -0.05, 0.20, P = .228). The effect size was robust in the leave-one-out sensitivity analysis. In meta-regression analysis, neither dose nor duration of supplementation with soy isoflavones was significantly associated with the effect size.

CONCLUSION

This meta-analysis of the 10 available randomized placebo-controlled trials revealed no significant effect of soy isoflavones treatment on plasma Lp(a) concentrations.