Tamoxifen alters the plasma concentration of molecules associated with cardiovascular risk in women with breast cancer undergoing chemotherapy

The impact of tamoxifen on apolipoproteins and lipoprotein(a) levels: an updated meta-analysis of randomized controlled trials

OBJECTIVE

The existing evidence regarding the impact of tamoxifen on lipoprotein(a) and apolipoproteins remains inconsistent. Therefore, this updated meta-analysis of randomized controlled trials (RCTs) aims to enhance the quality of evidence concerning the effects of tamoxifen on these lipid parameters.

METHODS

Eligible RCTs published up to October 2024 were meticulously selected through a comprehensive search. A meta-analysis was then performed using a random-effects model, and results were presented as the weighted mean difference (WMD) with a 95% confidence interval (CI).

RESULTS

Findings from the random-effects model revealed an increase in ApoA-I (WMD: 15.22 mg/dL, 95% CI: 6.43-24.01, P = 0.001), alongside decreases in ApoB (WMD: -9.33 mg/dL, 95% CI: -15.46 to -3.19, P = 0.003) and lipoprotein(a) (WMD: -3.35 mg/dL, 95% CI: -5.78 to -0.91, P = 0.007) levels following tamoxifen treatment in women. Subgroup analyses indicated a more significant reduction in lipoprotein(a) levels in RCTs with a duration of ≤24 weeks (WMD: -3.65 mg/dL) and in studies using tamoxifen doses of ≥20 mg/day (WMD: -4.53 mg/dL).

CONCLUSION

This meta-analysis provides evidence that tamoxifen leads to a decrease in lipoprotein(a) levels, along with reductions in ApoB and increases in ApoA-I among women.

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.

The effect of tamoxifen on estradiol, SHBG, IGF-1, and CRP in women with breast cancer or at risk of developing breast cancer: a meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The effects of tamoxifen on the serum levels of hormones and acute phase reactants have been studied previously, but study results have been inconsistent, especially in women with breast cancer. Hence, we conducted this meta-analysis of randomized controlled trials (RCTs) to try to clarify the effects of tamoxifen on estradiol, insulin-like growth factor 1 (IGF-1), sex hormone binding globulin (SHBG), and C-reactive protein (CRP) serum levels in women with breast cancer or at risk of developing breast cancer.

METHODS

Databases were systematically searched up to December 2023. The meta-analysis was generated through a random-effects model and is presented as the weighted mean difference (WMD) and 95 % confidence intervals (CI).

RESULTS

Nine publications were included in the present meta-analysis. The comprehensive findings from the random-effects model revealed an elevation in estradiol (WMD: 13.04 pg/mL, 95 % CI: 0.79, 25.30, p = 0.037) and SHBG levels (WMD: 21.26 nmol/l, 95 % CI: 14.85, 27.68, p = 0.000), as well as a reduction in IGF-1 (WMD: -14.41 μg/L, 95 % CI: -24.23, -4.60, p = 0.004) and CRP concentrations (WMD: -1.17 mg/dL, 95 % CI: -2.29, -0.05, p = 0.039) following treatment with tamoxifen in women with breast cancer or at risk of developing breast cancer, with no impact on IGFBP-3 levels (WMD: 0.11 μg/mL, 95 % CI: -0.07, 0.30, p = 0.240).

CONCLUSION

Tamoxifen administration seems to increase estradiol and SHBG levels and reduce CRP and IGF-1 levels in women with breast cancer or at risk of developing breast cancer. Further studies are needed to determine whether these changes have any clinical relevance.

A case of tamoxifen-induced hypertriglyceridemia monitoring the changes in lipoprotein fractions over time

BACKGROUND

Tamoxifen, which is one of the selective estrogen receptor modulators (SERMs), can bring out life-threatening complication, e.g. hypertriglyceridemia-induced acute pancreatitis, although it is rare. We precisely report changes in lipoprotein metabolism before and after tamoxifen discontinuation because there have been few reports of it.

CASE PRESENTATION

47-year-old premenopausal woman with dyslipidemia, type 2 diabetes, nonalcoholic fatty liver disease and chronic kidney disease was prescribed tamoxifen as adjuvant therapy after operation of breast cancer. She experienced severe tamoxifen-induced hypertriglyceridemia several months after dosing tamoxifen. Before cessation of tamoxifen, lipoprotein fraction test revealed marked stagnation of VLDL and IDL metabolisms, resulting in severe hypertriglyceridemia (serum triglyceride level was 1881 mg/dL). Seven days after tamoxifen withdrawal, lipoprotein fraction test showed that the metabolisms of endogenous lipoproteins were changed drastically.

CONCLUSIONS

From these results, we confirmed that tamoxifen certainly changes lipoprotein metabolism through suppression of post-heparin lipolytic activity. It is very important to evaluate the balance between benefit and risk before dosing tamoxifen and survey lipid profiles constantly during treatment to avoid life-threatening complication when prescription of tamoxifen is planned.

Effects of treatment with chemotherapy and/or tamoxifen on the biomarkers of cardiac injury and oxidative stress in women with breast cancer

There has been an increase in deaths from cardiovascular diseases following breast cancer therapy. Evidence has shown that this outcome is, in part, associated with cardiotoxicity induced by the chemotherapeutic drugs and the increase in oxidative stress. The aim of this study was to evaluate the effects of chemotherapy and hormone therapy with tamoxifen on the biomarkers of cardiac injury and oxidative stress in women with breast cancer.Thirty women were followed-up for 1 year and were divided into 3 groups according to the treatment protocol: women treated only with tamoxifen and clinical follow up for 12 months (Tam, n = 10); women treated only with chemotherapy for 6 months with clinical follow up for an additional 6-month period (Chemo, n = 10); and women who received chemotherapy for 6 months followed by a 6-month period only with tamoxifen therapy and clinical follow up (Chemo + Tam, n = 10). Analysis of the blood levels of cardiac troponin I (cTnI), advanced oxidation protein products (AOPP) and the activity of the plasmatic isoform of the antioxidant enzyme glutathione peroxidase (GPx) was performed before treatment (T0) and at 6 (T6) and 12 (T12) months after treatment.The Chemo group showed higher levels of cTnI (0.065 ± 0.006 ng/mL, P < .05) and AOPP (4.99 ± 0.84 μmol/L, P < .05) and reduced GPx activity (24.4 ± 1.1 nM/min/mL, P < .05) at T12 than the Tam group (cTnI: 0.031 ± 0.001 ng/mL; AOPP: 1.40 ± 0.10 μmol/L; GPx: 28.0 ± 0.7 nM/min/mL) and Chemo + Tam group (cTnI: 0.037 ± 0.002 ng/mL; AOPP: 2.53 ± 0.30 μmol/L; GPx: 29.5 ± 1.0 nM/min/mL).These data support the hypothesis that long-term oxidative stress after chemotherapy may have an impact on cardiovascular diseases and that tamoxifen has cardioprotective effects.

LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis

Leucine Rich Repeat Containing 8A (LRRC8A) is a required component of volume-regulated anion channels (VRACs). In vascular smooth muscle cells, tumor necrosis factor-α (TNFα) activates VRAC via type 1 TNFα receptors (TNFR1), and this requires superoxide (O₂^•-) production by NADPH oxidase 1 (Nox1). VRAC inhibitors suppress the inflammatory response to TNFα by an unknown mechanism. We hypothesized that LRRC8A directly supports Nox1 activity, providing a link between VRAC current and inflammatory signaling. VRAC inhibition by 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) impaired NF-κB activation by TNFα. LRRC8A siRNA reduced the magnitude of VRAC and inhibited TNFα-induced NF-κB activation, iNOS and VCAM expression, and proliferation of VSMCs. Signaling steps disrupted by both siLRRC8A and DCPIB included; extracellular O₂^•- production by Nox1, c-Jun N-terminal kinase (JNK) phosphorylation and endocytosis of TNFR1. Extracellular superoxide dismutase, but not catalase, selectively inhibited TNFR1 endocytosis and JNK phosphorylation. Thus, O₂^•- is the critical extracellular oxidant for TNFR signal transduction. Reducing JNK expression (siJNK) increased extracellular O₂^•- suggesting that JNK provides important negative feedback regulation to Nox1 at the plasma membrane. LRRC8A co-localized by immunostaining, and co-immunoprecipitated with, both Nox1 and its p22phox subunit. LRRC8A is a component of the Nox1 signaling complex. It is required for extracellular O₂^•- production, which is in turn essential for TNFR1 endocytosis. These data are the first to provide a molecular mechanism for the potent anti-proliferative and anti-inflammatory effects of VRAC inhibition.

Comparative effects of estrogen, raloxifene and tamoxifen on endothelial dysfunction, inflammatory markers and oxidative stress in ovariectomized rats

AIM

Endothelial dysfunction is considered a premature indication of atherosclerosis and vessel damage and is present in the postmenopausal period. This study compares the influence of estrogen, raloxifene and tamoxifen on factors that affect endothelial function in ovariectomized (OVX) rats.

MAIN METHODS

The rats were divided into: SHAM; OVX; OVX+estrogen (0.5 μg/kg/day); OVX+raloxifene (2 mg/kg/day) and OVX+tamoxifen (1 mg/kg/day) groups. The acetylcholine vasorelaxation response was evaluated in the mesenteric vascular bed. The vascular oxidative stress and serum inflammatory cytokine levels were monitored, and analyses of eNOS and iNOS were performed.

KEY FINDINGS

The acetylcholine-induced responses obtained in the OVX were lower than those obtained in the SHAM, and all treatments restored this response. l-NAME reduced and equalized the acetylcholine-induced response in all groups. The attenuation of the acetylcholine-induced responses by aminoguanidine was greater in the OVX. Endothelial dysfunction in OVX was associated with oxidative stress and an increase in iNOS and decrease in eNOS expression. Except for the production of reactive oxidative species (ROS) in the OVX+tamoxifen, treatments improved the nitric oxide component of the relaxation response and normalized both the oxidative stress and the expression of those signaling pathway enzymes. Serum levels of TNF-α and IL-6 were increased in OVX, and treatments normalized these levels.

SIGNIFICANCE

Raloxifene and tamoxifen have similar anti-inflammatory effects that may be important in improving vascular dysfunction. Tamoxifen did not affect the ROS but improved endothelial dysfunction. The protective effect on endothelial function by these treatments provides evidence of their potential cardiovascular benefits in the postmenopausal period.

Hormone therapy with tamoxifen reduces plasma levels of NT-B-type natriuretic peptide but does not change ventricular ejection fraction after chemotherapy in women with breast cancer

The objective of this study was to evaluate the effect of tamoxifen on the plasma concentration of NT-pro-B-type natriuretic peptide (NT-proBNP) in women undergoing chemotherapy for breast cancer and to correlate changes in NT-proBNP with the left ventricular ejection fraction (LVEF). Over a period of 12 months, we followed 60 women with a diagnosis of breast cancer. The patients were separated into a group that received only chemotherapy (n=23), a group that received chemotherapy + tamoxifen (n=21), and a group that received only tamoxifen (n=16). Plasma levels of NT-proBNP were assessed at 0 (T0), 6 (T6), and 12 (T12) months of treatment, and echocardiography data were assessed at T0 and T12. Plasma NT-proBNP levels were increased in the chemotherapy-only group at T6 and T12, whereas elevated NT-proBNP levels were only found at T6 in the chemotherapy + tamoxifen group. At T12, the chemotherapy + tamoxifen group exhibited a significant reduction in the peptide to levels similar to the group that received tamoxifen alone. The chemotherapy-only group exhibited a significant decrease in LVEF at T12, whereas the chemotherapy + tamoxifen and tamoxifen-only groups maintained levels similar to those at the beginning of treatment. Treatment with tamoxifen for 6 months after chemotherapy significantly reduced the plasma levels of NT-proBNP and did not change LVEF in women with breast cancer.

Tamoxifen therapy in breast cancer: do apolipoprotein E genotype and menopausal state affect plasma lipid changes induced by the drug?

OBJECTIVE

This study examines the lipid profile change produced in response to tamoxifen (TAM) treatment, and its possible relationship with both apolipoprotein E genotype and menopausal state in patients with breast cancer.

METHODS

Blood samples were collected from 86 Spanish women with breast cancer before initiating TAM treatment and in the following 6, 12 and 18 months of treatment. Plasma lipid levels (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol) were determined using an automatic analyzer. Genotypes for apolipoprotein E (ApoE) were identified by PCR-RFLP using the HhaI enzyme.

RESULTS

In all patients, significant reductions in total cholesterol and LDL-cholesterol concentrations and a significant increase in triglyceride concentrations were observed after 6, 12, and 18 months of TAM treatment compared to baseline (p<0.01 for each time point). In the subset of APOE4-negative patients, triglyceride concentrations also significantly increased after 6, 12, and 18 months of treatment (p=0.019, p=0.045, p=0.001, respectively), while APOE4-positive patients showed no significant lipid changes at 12 and 18 months. However, after 18 months of TAM treatment the overall triglyceride concentrations had risen by 24.75% in APOE4-negative patients vs 29.9% in APOE4-positive patients. In postmenopausal women, significant reductions in total cholesterol, LDL-cholesterol and LDL/HDL ratios were observed at each time point (p<0.020 for each).

CONCLUSIONS

TAM treatment induced similar plasma triglyceride increases in patients with positive or negative APOE genotype. Compared to premenopausal patients, postmenopausal breast cancer patients showed a more beneficial lipid profile change in response to treatment.

Association of tamoxifen use and reduced cardiovascular events among asian females with breast cancer

BACKGROUND

Tamoxifen is used for breast cancer treatment and has been reported to be beneficial for the cardiovascular system, but it is unclear whether tamoxifen exhibits a favorable cardiovascular effect in Asian patients.

METHODS AND RESULTS

From January, 1998 to December, 2006, a breast cancer cohort study was conducted using the Taiwan National Health Insurance database. Patients were divided according to whether tamoxifen was used. Study endpoints were occurrence of acute myocardial infarction (AMI), ischemic or hemorrhagic stroke and total cardiovascular events. A total of 3,690 female subjects were enrolled (mean age 50.1±11.3), 2,056 of whom received tamoxifen and 1,634 did not. During a mean follow-up of 6.9 years, the tamoxifen group had a significantly lower incidence of AMI (0.15% vs. 0.67%, P=0.008), ischemic stroke (1.99% vs. 3.30%, P=0.008), hemorrhagic stroke (0.15% vs. 0.55%, P=0.029), and total cardiovascular events (2.24% vs. 4.16%, P<0.001) than the non-exposed group. After adjusting for comorbidities, tamoxifen was independently associated with a reduced risk of myocardial infarction (hazard ratio [HR] 0.22; 95% confidence interval [CI] 0.07-0.70, ischemic stroke (HR 0.52; 95% CI 0.35-0.78), hemorrhagic stroke (HR 0.25; 95% CI 0.07-0.92), and total cardiovascular events (HR 0.54; 95% CI 0.37-0.78).

CONCLUSIONS

In Asian female breast cancer patients, tamoxifen use was associated with reduced risks of AMI, ischemic, hemorrhagic stroke and total cardiovascular events.