Adjuvant tamoxifen influences the lipid profile in breast cancer patients

The effect of tamoxifen as an adjuvant therapy for breast cancer on apolipoproteins and lipoprotein(a) concentrations in women: A meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Tamoxifen has been used in the management of breast cancer. The available evidence on the effect of tamoxifen on lipoprotein(a) and apolipoproteins is controversial. Hence, this meta-analysis of randomized controlled trials (RCTs) was conducted to increase the quality of evidence on the effect of tamoxifen on lipoprotein(a) and apolipoproteins.

METHODS

Eligible RCTs published up to September 2023 were carefully selected following a comprehensive search. Thereafter, a meta-analysis was conducted using a random-effects model and the results were presented as the weighted mean difference (WMD) with a 95 % confidence interval (CI).

RESULTS

The results from the random-effects model indicated a rise in ApoA-I (WMD: 16.24 mg/dL, 95 % CI: 5.35, 27.12, P = 0.003), and a decrease in ApoB (WMD: -9.37 mg/dL, 95 % CI: -15.16, -3.59, P = 0.001) and lipoprotein(a) (WMD: -3.24 mg/dL, 95 % CI: -5.66, -0.83, P < 0.001) concentrations following tamoxifen administration in women. Furthermore, a more pronounced decrease in ApoB (WMD: -12.86 mg/dL, 95 % CI: -19.78, -5.93, P < 0.001) and elevation in ApoA-1 levels (WMD: 51.97 mg/dL, 95 % CI: 45.89, 58.05, P < 0.001) were identified in a single study on patients with breast cancer.

CONCLUSION

The current meta-analysis demonstrated an increase of ApoA-I and a decrease of ApoB and lipoprotein(a) levels after treatment with tamoxifen in women.

Aromatase enzyme: Paving the way for exploring aromatization for cardio-renal protection

Documented male-female differences in the risk of cardiovascular and chronic kidney diseases have been largely attributed to estrogens. The cardiovascular and renal protective effects of estrogens are mediated via the activation of estrogen receptors (ERα and ERβ) and G protein-coupled estrogen receptor, and involve interactions with the renin-angiotensin-aldosterone system. Aromatase, also called estrogen synthase, is a cytochrome P-450 enzyme that plays a pivotal role in the conversion of androgens into estrogens. Estrogens are biosynthesized in gonadal and extra-gonadal sites by the action of aromatase. Evidence suggests that aromatase inhibitors, which are used to treat high estrogen-related pathologies, are associated with the development of cardiovascular events. We review the potential role of aromatization in providing cardio-renal protection and highlight several meta-analysis studies on cardiovascular events associated with aromatase inhibitors. Overall, we present the potential of aromatase enzyme as a fundamental contributor to cardio-renal protection.

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.

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.

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.

Antimicrobial, Antitumor and Side Effects Assessment of a Newly Synthesized Tamoxifen Analog

BACKGROUND

Tamoxifen citrate is a very prevalent drug marketed under several trade names like Apo-Tamox, Nolvadex, Tamec, Tamizam, and Tamoplex. This molecule is approved by the FDA for breast cancer treatment. Some studies have shown that tamoxifen has anti-tuberculosis and antiparasitic activities. Like any drug, tamoxifen possesses side effects, more or less dangerous.

AIMS

Basically, this work is a comparative study that aims to: primarily compare the antimicrobial and antitumor activities of tamoxifen and a newly synthesized tamoxifen analog; and to determine the molecule with lesser side effects.

METHODS

Three groups of mice were injected with tamoxifen citrate and compound 2(1,1-bis[4-(3- dimethylaminopropoxy)phenyl]-2-phenyl-but-1-ene dihydrochloride) at doses corresponding to C1 (1/10), C2 (1/50), and C3 (1/100) to compound 2 lethal dose (LD50 = 75 mg/kg) administered to adult mice. A group of noninjected mice served as a study control.

RESULTS

Experimental results suggest that compound 2 has better antitumor and antimicrobial activity than tamoxifen citrate besides its lower toxicity effects.

CONCLUSION

The results obtained from the present study confirmed the antitumor and antimicrobial effect of tamoxifen citrate and its hematological side effects. Compound 2 seems to be more effective than tamoxifen citrate for antitumor and antimicrobial treatment while having less hematological side effects and less disruption of the blood biochemical parameters. These findings encourage us to perform further studies on compound 2 and test it for other therapeutic uses for which tamoxifen was found effective.

Emerging roles of low-density lipoprotein in the development and treatment of breast cancer

Breast cancer is a heterogeneous disease with increasing incidence and mortality and represents one of the most common cancer types worldwide. Low-density lipoprotein (LDL) is a complex particle composed of several proteins and lipids, which carries cholesterol into peripheral tissues and also affects the metabolism of fatty acids. Recent reports have indicated an emerging role of LDL in breast cancer, affecting cell proliferation and migration, thereby facilitating disease progression. However, controversy still exists among distinct types of breast cancer that can be affected by LDL. Classical therapeutic approaches, such as radiotherapy, chemotherapy, and lipid-lowering drugs were also reported as affecting LDL metabolism and content in breast cancer patients. Therefore, in this review we summarized and discussed the role of LDL in the development and treatment of breast cancer.

Therapy-induced cardiotoxicity in breast cancer patients: a well-known yet unresolved problem

Breast cancer is the second most commonly diagnosed cancer, being one of the main health issues that needs to be addressed worldwide. New therapies have led to a remarkable increase in survival rates, which is unfortunately overshadowed by their negative impact on cardiac structure and function in disease-free patients. Since anthracyclines and trastuzumab cause the most undesired outcome in breast cancer patients - cardiac-related mortality, they have been widely studied. However, other therapies (such as hormonal therapy, tyrosine kinase inhibitors, anti-VEGF drugs etc.) can also affect the cardiovascular system and lead to ischemia, hypertension or vascular thromboembolism. Even though excessive research has been conducted in thepast decades, there are still no guidelines regarding the most adequate methods neither to detect and prevent severe cardiotoxicity that can finally lead to heart failure and ultimately death nor for the further management of patients after cardiotoxicity is detected. Biomarkers of ischemia (troponins T and I) and of overload (BNP and NT-proBNP) in association with periodic echocardiographies (assessment of the global longitudinal strain) are two of the most important means used by physicians in the evaluation of cardiac disease in this group of patients. Given that no internationally accepted guidelines for screening and surveillance of different populations exist, the cardio-oncology team is crucial in the management of these patients, their collaboration resulting in individualized treatment regimens. After careful evaluation of different variables (treatment effects, malignancy status, and the patient's pre-existing conditions), a decision is made to either reduce the dosage or rate of administration, change the medication or interrupt the treatment and initiate the cardioprotective therapeutic associations. Consequently, it is an absolute necessity the development of customized treatment guidelines and the conduction of multiple clinical studies in order to demonstrate their effect on long-term survival.

Cholesterol, Cholesterol-Lowering Medication Use, and Breast Cancer Outcome in the BIG 1-98 Study

Purpose

Cholesterol-lowering medication (CLM) has been reported to have a role in preventing breast cancer recurrence. CLM may attenuate signaling through the estrogen receptor by reducing levels of the estrogenic cholesterol metabolite 27-hydroxycholesterol. The impact of endocrine treatment on cholesterol levels and hypercholesterolemia per se may counteract the intended effect of aromatase inhibitors.

Patients and Methods

The Breast International Group (BIG) conducted a randomized, phase III, double-blind trial, BIG 1-98, which enrolled 8,010 postmenopausal women with early-stage, hormone receptor–positive invasive breast cancer from 1998 to 2003. Systemic levels of total cholesterol and use of CLM were measured at study entry and every 6 months up to 5.5 years. Cumulative incidence functions were used to describe the initiation of CLM in the presence of competing risks. Marginal structural Cox proportional hazards modeling investigated the relationships between initiation of CLM during endocrine therapy and outcome. Three time-to-event end points were considered: disease-free-survival, breast cancer–free interval, and distant recurrence–free interval.

Results

Cholesterol levels were reduced during tamoxifen therapy. Of 789 patients who initiated CLM during endocrine therapy, the majority came from the letrozole monotherapy arm (n = 318), followed by sequential tamoxifen-letrozole (n = 189), letrozole-tamoxifen (n = 176), and tamoxifen monotherapy (n = 106). Initiation of CLM during endocrine therapy was related to improved disease-free-survival (hazard ratio [HR], 0.79; 95% CI, 0.66 to 0.95; P = .01), breast cancer–free interval (HR, 0.76; 95% CI, 0.60 to 0.97; P = .02), and distant recurrence–free interval (HR, 0.74; 95% CI, 0.56 to 0.97; P = .03).

Conclusion

Cholesterol-lowering medication during adjuvant endocrine therapy may have a role in preventing breast cancer recurrence in hormone receptor–positive early-stage breast cancer. We recommend that these observational results be addressed in prospective randomized trials.

Effects of breast cancer on chronic disease medication adherence among older women

PURPOSE

The purpose of this study was to determine the effects of breast cancer on chronic disease medication adherence among older women.

METHODS

The Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked data and a 5% random sample of Medicare enrollees were used. Stage I-III breast cancer patients diagnosed in 2008 and women without cancer were eligible. Three cohorts of medication users 66+ years were identified using diagnosis codes and prescription fill records: diabetes, hypertension, and lipid disorders. For each cohort, breast cancer patients were frequency matched to comparison women by age and geographic area. Medication adherence was measured by the proportion of days covered and medication persistence.

RESULTS

During the post-baseline period, the percentage of breast cancer patients who were non-adherent was 26.2% for diabetes medication, 28.9% for lipid-lowering medication, and 14.2% for hypertension medication. Breast cancer patients experienced an increased odds of diabetes medication non-adherence [odds ratio (OR) = 1.44; 95% confidence interval (CI) = 1.07 to 1.95] and were more likely to be non-persistent with diabetes medication (hazard ratio = 1.31; 95%CI: 1.04 to 1.66) relative to women without cancer. The study failed to show a difference between breast cancer and comparison women in the odds of non-adherence to hypertensive (OR = 0.87; 95%CI: 0.71 to 1.05) or lipid-lowering medication (OR = 0. 91; 95%CI: 0.73 to 1.13) with a proportion of days covered threshold of 80%.

CONCLUSION

Special attention should be given to the coordination of primary care for older breast cancer patients with diabetes. Copyright © 2016 John Wiley & Sons, Ltd.

Cardiac risk in the treatment of breast cancer: assessment and management

As the number of long-term breast cancer survivors has increased, the side effects of adjuvant cancer therapy, such as cardiac toxicity, remain clinically important. Although the cardiac toxicity due to anthracyclines, radiotherapy, or trastuzumab is well-documented, several issues need to be clarified and are the subjects of extensive ongoing clinical research. This review summarizes the incidence of cardiac toxicity due to breast cancer adjuvant therapy and highlights the current trends in early detection and management of cardiac toxicities.