Comparison of changes in the lipid profile of postmenopausal women with early stage breast cancer treated with exemestane or letrozole

The effect of exemestane administration on the lipid profile in women: Meta-analysis of randomized controlled trials

OBJECTIVE

Postmenopausal women are prone to develop cardiovascular disorders. In addition, cardiovascular risk in women can be influenced by the long-term prescription of drugs that lead to estrogen deprivation, e.g., aromatase inhibitors, and that can cause dyslipidemia. Little is known about the impact of exemestane, an aromatase inhibitor, on serum lipids' concentration in women. Hence, we conducted a meta-analysis of randomized controlled trials (RCTs) to assess the influence of this pharmacological agent on the lipid profile in women.

METHODS

The Scopus, Web of Science, PubMed/Medline and EMBASE databases were searched by two surveyors for manuscripts published from the inception of these databases until April 3rd, 2023. No language restrictions were applied to the search. The random effects model was used to generate the combined results as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

In total, 8 eligible RCTs were included in the meta-analysis. Overall results from the random effects model indicate that exemestane administration increases LDL-C (WMD: 4.42 mg/dL, 95 % CI: 0.44, 8.41, P = 0.02) and decreases HDL-C (WMD: -6.03 mg/dL, 95 % CI: -7.77, -4.29, P < 0.001) and TC (WMD: -5.40 mg/dL, 95 % CI: -9.95, -0.86, P = 0.02) levels, respectively. Moreover, exemestane prescription only lowered TG concentrations when it was administered for < 12 months (WMD: -14.60 mg/dL, 95 % CI: -23.57 to -5.62, P = 0.001).

CONCLUSION

Currently available evidence suggests that the administration of exemestane in females increases LDL-C values and reduces HDL-C, TC, and, when prescribed for less than 12 months, TG concentrations.

Lipid changes during endocrine therapy in early-stage breast cancer patients: A real-world study

BACKGROUND

Endocrine drugs may affect lipid metabolism in breast cancer (BC) patients. This study explores lipid changes in early-stage BC patients taking different endocrine drugs.

METHODS

The changing trend of blood lipid during endocrine therapy in 2756 BC patients from January 2013 to December 2021 was retrospectively analyzed. The changes in four lipid parameters were assessed by the Generalized Linear Mixed Model, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C). These parameters were quantified at baseline and at 6, 12, 18, 24, 36, 48, 60, and 72 months after endocrine therapy initiation. Furthermore, a subgroup analysis according to menopausal status or medication types was conducted.

RESULTS

A total of 1201 patients taking aromatase inhibitors (AIs), including anastrozole (ANA), letrozole (LET), or exemestane (EXE), and 1555 patients taking toremifene (TOR) were enrolled. TC and TG levels showed a significantly elevated trend during 5 years of treatment (P < 0.05). HDL-C levels increased from baseline in the TOR group (P < 0.05). Compared with the postmenopausal AI group, the increasing trends of TC, TG, and LDL-C in the premenopausal AI group were more evident with the extension of time (β = 0.105, 0.027, 0.086, respectively). Within 3 years, TC, TG, and LDL-C levels in the ANA and LET groups were significantly higher than baseline (P < 0.05). Moreover, the levels of TG in the EXE group were significantly lower than that in the ANA or LET group (P < 0.05), but this significant difference disappeared after 3 years.

CONCLUSIONS

AIs significantly influenced lipid profiles more than TOR. AIs had a greater effect on blood lipids in premenopausal patients. Steroidal AIs (EXE) may affect lipid levels less than nonsteroidal AIs (ANA and LET).

Dyslipidemia is associated with a poor prognosis of breast cancer in patients receiving neoadjuvant chemotherapy

BACKGROUND

Lipid metabolism disorders may be involved in the occurrence and development of breast cancer. This study aimed to investigate the serum lipid changes during neoadjuvant chemotherapy for breast cancer and the effect of dyslipidemia on the prognosis of breast cancer patients.

METHODS

We collected the data from 312 breast cancer patients who underwent surgery after receiving standard neoadjuvant therapy. χ² test and T-test were employed to analyze the effect of chemotherapy on the serum lipid metabolism of patients. The effects of dyslipidemia on the disease-free survival (DFS) of patients with breast cancer were analyzed by χ² test and COX regression analysis.

RESULTS

A total of 56 out of 312 patients (17.9%) suffered from relapse. The baseline serum lipid level of the patients was significantly correlated with their age and body mass index (BMI) (p < 0.05). Chemotherapy increased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol, but decreased the level of high-density lipoprotein cholesterol (p < 0.001). Preoperative dyslipidemia was significantly associated with the axillary pCR rate (p < 0.05). COX regression analysis revealed that the full-course serum lipid level (HR = 1.896 [95%CI 1.069-3.360]; p = 0.029), N stage (HR = 4.416 [95%CI 2.348-8.308]; p < 0.001) and the total pCR rate (HR = 4.319 [95%CI 1.029-18.135]; p = 0.046) acted as prognostic factors affecting DFS in breast cancer. The relapse rate in patients with a high level of total cholesterol was higher than that in patients with a high level of triglycerides (61.9% vs 30.0%; p < 0.05).

CONCLUSIONS

Dyslipidemia deteriorated after chemotherapy. The full-course serum lipid level may thus serve as a blood marker for predicting breast cancer prognosis. Serum lipids should therefore be closely monitored in breast cancer patients throughout the treatment course, and patients with dyslipidemia should be treated in a timely manner.

Lipid Changes During Endocrine Therapy in Breast Cancer Patients: The Results of a 5-Year Real-World Retrospective Analysis

Background

The aim of this study was to investigate the status of serum lipids during endocrine therapy.

Methods

We retrospectively analysed lipid profiles during the 5-year treatment of 1487 consecutive postoperative BC patients. Lipid parameters included triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C). Those biomarkers were measured at baseline and 1, 2, 3, 4 and 5 years following the initiation of endocrine therapy.

Results

For premenopausal BC patients, LDL levels rapidly decreased at 1 year in the tamoxifen (TAM) group compared with baseline levels (p<0.05), and this decline remained for the following 4 years. Additionally, LDL levels were significantly lower in the TAM group than in the nonendocrine group at all assessment time points (p<0.05). Similarly, TC levels also decreased in the TAM group compared with baseline levels at all assessment time points (p<0.05), and compared with the levels in the nonendocrine group, TC levels were also lower for the first 4 years. For postmenopausal BC patients, there was no significant difference in the lipid profiles (TG, TC, LDL and HDL) in the letrozole (LET), anastrozole (ANA) or exemestane (EXE) groups compared with the nonendocrine group. For patients who received TAM, compared with the nonendocrine group, TC levels decreased at 1 year, and LDL levels decreased at 1 and 2 years.

Conclusions

TAM may improve LDL and TC levels in premenopausal BC patients. In postmenopausal BC patients, aromatase inhibitors (AIs) may have no adverse effects on lipid profiles, and TAM may have limited beneficial effects on serum lipids.

Metabolic Syndrome and Breast Cancer: Prevalence, Treatment Response, and Prognosis

Metabolic syndrome is a type of multifactorial metabolic disease with the presence of at least three factors: obesity, diabetes mellitus, low high-density lipoprotein, hypertriglyceridemia, and hypertension. Recent studies have shown that metabolic syndrome and its related components exert a significant impact on the initiation, progression, treatment response, and prognosis of breast cancer. Metabolic abnormalities not only increase the disease risk and aggravate tumor progression but also lead to unfavorable treatment responses and more treatment side effects. Moreover, biochemical reactions caused by the imbalance of these metabolic components affect both the host general state and organ-specific tumor microenvironment, resulting in increased rates of recurrence and mortality. Therefore, this review discusses the recent advances in the association of metabolic syndrome and breast cancer, providing potential novel therapeutic targets and intervention strategies to improve breast cancer outcome.

Steroidal aromatase inhibitors have a more favorable effect on lipid profiles than nonsteroidal aromatase inhibitors in postmenopausal women with early breast cancer: a prospective cohort study

Background:

Aromatase inhibitors (AIs) influence blood lipid profiles. However, relatively few studies have directly compared the treatment effects of steroidal and nonsteroidal AIs.

Methods:

A prospective single-center cohort study was conducted to investigate the effects of steroidal and nonsteroidal AIs on lipid profiles during the first 24 months of endocrine therapy in hormone receptor-positive postmenopausal patients with early breast cancer. The primary endpoint was the cumulative incidence of lipid events, while the secondary endpoints were changes in lipid profiles and lipid event-free survival.

Results:

Comparison of the lipid profiles of the two groups showed that triglycerides (TGs) and total cholesterol (TC) levels were significantly higher in the nonsteroidal AI group over 24 months (p < 0.05), whereas low-density lipoprotein cholesterol (LDL-C) was significantly higher only at 3 months (p = 0.017) and 6 months (p = 0.026). High-density lipoprotein cholesterol (HDL-C) was significantly lower in the steroidal group at all time points (p < 0.05), except at 18 months (p = 0.085). The cumulative incidence of lipid events in the steroidal and nonsteroidal groups at 24 months was 25.3% and 37.0%, respectively. Multivariate analysis results indicated that TG, LDL-C, and steroidal AIs were independently associated with blood lipid events.

Conclusion:

This trial showed that a significantly higher cumulative incidence of lipid events occurred in the nonsteroidal AI group than in the steroidal AI group, which indicated that steroidal AIs exerted a protective effect against blood lipid events in postmenopausal women receiving an AI as adjuvant therapy for breast cancer.

ClinicalTrials.gov identifier:

NCT02765373

Comparative effectiveness of tamoxifen, toremifene, letrozole, anastrozole, and exemestane on lipid profiles in breast cancer patients: A network meta-analysis

BACKGROUND

Adjuvant endocrine therapy is a vital portion of postoperative comprehensive treatment for breast cancer patients. In recent years, studies have shown that endocrine therapy has a certain impact on the serum lipids of breast cancer patients, and the changes of lipid profiles may bring a series of problems. However, very few studies focus on this issue to date. The results of these studies are inconsistent, and the influence of different adjuvant endocrine modalities on lipid profiles still remains controversial. In order to better explore this issue, we conduct this network meta-analysis.

METHOD

The protocol followed preferred reporting items for systematic reviews and meta-analyses protocols. Three main databases (PubMed, Embase, and the Cochrane Library) will be searched systematically for eligible randomized controlled trials without language restriction. In addition, a manual search of the references of relevant published studies will also be considered. Two reviewers will conduct studies selection, data extraction, and risk of bias assessment independently. The primary outcome is the variation of biochemical parameters - the serum lipid profiles (cholesterol, triglyceride, high-density lipoprotein, low low-density lipoprotein).

RESULTS

The results will provide useful information about the side effects of different adjuvant endocrine drugs on lipid profiles in postoperative breast cancer patients (estrogen receptor-positive and/or progesterone receptor-positive).

CONCLUSION

The findings of this study will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42019129850.

Effects of a web-based expert support self-management program (WEST) for women with breast cancer: A randomized controlled trial

INTRODUCTION

This study was a randomized controlled trial that examined the effects of a web-based expert support self-management program (WEST) on metabolic syndrome risk factors and self-efficacy among Korean women with breast cancer.

METHODS

Participants were 60 women with breast cancer (30 participants each in both the experimental and control groups) who also had metabolic risk factors. WEST is based on the self-efficacy theory and is a self-health management program consisting of a web-based program, DIETEX (which entails keeping a health diary, identifying a lifestyle type, inputting personal health information), and expert support. WEST was provided to the experimental group once a week for 24 weeks. Metabolic syndrome risk factors and self-efficacy of the experimental and control groups were examined pre-intervention and at 12 and 24 weeks after intervention.

RESULTS

The decreases in body fat, body fat percentage, and waist circumference were greater in the experimental group than in the control group at 24 weeks (p = 0.019, p = 0.025, and p = 0.038, respectively).

DISCUSSION

The present study can provide basic data for the development and application of interventions for women with breast cancer in the future. Additionally, we propose that WEST be included in the treatment process to complement the intervention of medical personnel for improving metabolic risk factors in women with breast cancer.

Are aromatase inhibitors associated with higher myocardial infarction risk in breast cancer patients? A Medicare population-based study

BACKGROUND

Theoretically, the estrogen deprivation induced by aromatase inhibitors (AIs) might cause ischemic heart disease, but empiric studies have shown mixed results. We aimed to compare AIs and tamoxifen with regard to cardiovascular events among older breast cancer patients outside of clinical trials. We hypothesized that AIs increase the risk of myocardial infarction.

METHODS

We identified women age ≥67 years diagnosed with breast cancer from June 30, 2006 to June 1, 2008 in the surveillance, epidemiology, and end results (SEER)-Medicare database, treated with either tamoxifen or an AI, and followed through December 31, 2012. To compare myocardial infarction (MI) risk for the treatment groups of AIs vs tamoxifen, we developed and assigned stabilized probability of treatment weights and used the Fine and Gray model for time to MI with death not related to MI as a competing risk.

RESULTS

Of the cohort of 5648 women, 4690 were treated with AIs and 958 with tamoxifen; a total of 251 patients developed MI, and 22 patients died of MI during the study period while 476 died of other causes. The hazard for MI was not significantly different between AI vs tamoxifen groups (HR = 1.01, 95% CI 0.72-1.42), after adjusting for the following known MI risk factors at the start of adjuvant therapy: diabetes, ischemic heart disease, congestive heart failure, MI, and peripheral vascular disease.

CONCLUSIONS

In this SEER-Medicare-based population study, there were no significant differences in the risk of MI between AI and tamoxifen users after adjustment for known risk factors.

Comparison of lipid profiles and inflammation in pre- and post-menopausal women with cerebral infarction and the role of atorvastatin in such populations

Background

The risks of atherosclerotic cardiovascular and cerebrovascular diseases in women rapidly increase with age in post-menopausal women. We aimed to investigate the lipid profiles in peri-menopausal women with cerebral infarction and to explore the effects of atorvastatin intervention.

Methods

We collected women aged 40-60 with cerebral infarction between January 2013 and December 2016. Atorvastatin was applied for 6 months in all included patients. Blood lipid profiles, serum pro-inflammation cytokines, intracranial plaque and NIH stroke scale (NIHSS) scores were evaluated before and after atorvastatin treatment.

Results

Totally 210 patients were included. Before atorvastatin treatment, post-menopausal patients had significantly higher levels of triglyceride, cholesterol, low-density lipoprotein and a reduced level of high-density lipoprotein than those in pre-menopausal patients. Blood levels of pro-inflammatory cytokines including interleukin (IL)-1, IL-6 and tumor necrosis factor-α were higher in post-menopausal patients, who had larger intracranial plaques than pre-menopausal patients. Consistently, post-menopausal patients had higher NIHSS scores than pre-menopausal ones. Atorvastatin reduced NIHSS scores and improved dyslipidemia in patients and eliminated the differences of these parameters between pre- and post-menopausal patients.

Conclusions

Post-menopausal patients were severer than pre-menopausal patients in terms of dyslipidemia, systemic inflammation and NIHSS scores. Atorvastatin may be beneficial for women with cerebral infarction.

Comparison of Changes in the Lipid Profiles of Eastern Chinese Postmenopausal Women With Early-Stage Breast Cancer Treated With Different Aromatase Inhibitors: A Retrospective Study

Cardiovascular morbidity is closely associated with serum lipid level. We aimed to investigate the effects of different aromatase inhibitors, including letrozole, anastrozole, and exemestane, on the lipid profile of eastern Chinese breast cancer patients. We evaluated a retrospective cohort of eastern Chinese postmenopausal women with early-stage breast cancer who received aromatase inhibitors. A total of 116 postmenopausal women with early-stage breast cancer without prior cardiovascular disease were included. Lipid changes at 3, 6, 12, and 24 months were compared across the endocrine therapy categories. Our data demonstrated that exemestane treatment significantly decreased triglyceride level compared with letrozole after 24 months. However, the aromatase inhibitors had almost equivalent impacts on high-density liportein cholesterol, low-density lipoprotein cholesterol, and triglyceride after long-term aromatase inhibitor treatment. As a small-size retrospective study, our data do not support a judgment about whether one AI or another carries more or less risk in terms of lipid disorders in eastern Chinese breast cancer patients. The exact effects need further randomized, controlled trials to investigate.

Relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors for breast cancer

OBJECTIVE

To analyze the relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors (AIs) for the treatment of breast cancer.

STUDY DESIGN

Cross-sectional study, conducted with 101 postmenopausal women (aged 50-80 years). The sample was divided into two groups; group without cancer (GW; n=65) and breast cancer group treated with AIs (GC; n=36). Physical activity (PA) was evaluated by questionnaire. Correlations between physical activity and metabolic variables were made by Pearson's correlation coefficient and the magnitude of these relationships by linear regression.

RESULTS

In GW, there were observed significant inverse correlations between physical activity and VLDL cholesterol (β=-0.036; 95% CI=-0.068; -0.004); triglycerides (β=-0.036; 95% CI=-0.015; -0.002); glycose (β=-0.029; 95% CI=-0.047; -0.012); and C-reactive protein (β=-0.44; 95% CI=-0.085; -0.003). However, for women under treatment of AIs there was no relationship between physical activity and metabolic variables.

CONCLUSION

The amount of physical activity practice is inversely related to lipid profile, glucose and C-reactive protein in women without breast cancer. This relation was not observed in the cancer survivors, suggesting that the use of aromatase inhibitors could influence or low intensity of physical activity.

Adjuvant endocrine therapy in women with oestrogen-receptor-positive breast cancer: how should the skeletal and vascular side effects be assessed and managed?

Adjuvant endocrine therapy provides oncological benefits in women with early oestrogen-receptor-positive breast cancer, but has adverse effects consequent to induced oestradiol deficiency. Bone loss is accelerated, predisposing to increased fracture risk. Metabolic effects include changes in lipid metabolism and body composition although effects on cardiovascular risk are still unclear. Women commencing endocrine therapy should be proactively counselled about and monitored for these and other therapy-related complications including arthralgia and vasomotor symptoms. We provide strategies for prevention and management of these adverse effects, based, where available, on randomized controlled trial evidence specific to breast cancer survivors receiving endocrine treatment.

American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline

The purpose of the American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline is to provide recommendations to assist primary care and other clinicians in the care of female adult survivors of breast cancer. A systematic review of the literature was conducted using PubMed through April 2015. A multidisciplinary expert workgroup with expertise in primary care, gynecology, surgical oncology, medical oncology, radiation oncology, and nursing was formed and tasked with drafting the Breast Cancer Survivorship Care Guideline. A total of 1,073 articles met inclusion criteria; and, after full text review, 237 were included as the evidence base. Patients should undergo regular surveillance for breast cancer recurrence, including evaluation with a cancer-related history and physical examination, and should be screened for new primary breast cancer. Data do not support performing routine laboratory tests or imaging tests in asymptomatic patients to evaluate for breast cancer recurrence. Primary care clinicians should counsel patients about the importance of maintaining a healthy lifestyle, monitor for post-treatment symptoms that can adversely affect quality of life, and monitor for adherence to endocrine therapy. Recommendations provided in this guideline are based on current evidence in the literature and expert consensus opinion. Most of the evidence is not sufficient to warrant a strong evidence-based recommendation. Recommendations on surveillance for breast cancer recurrence, screening for second primary cancers, assessment and management of physical and psychosocial long-term and late effects of breast cancer and its treatment, health promotion, and care coordination/practice implications are made.

This guideline was developed through a collaboration between the American Cancer Society and the American Society of Clinical Oncology and has been published jointly by invitation and consent in both CA: A Cancer Journal for Clinicians and Journal of Clinical Oncology. Copyright © 2015 American Cancer Society and American Society of Clinical Oncology. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without written permission by the American Cancer Society or the American Society of Clinical Oncology.

American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline

Answer questions and earn CME/CNE The purpose of the American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline is to provide recommendations to assist primary care and other clinicians in the care of female adult survivors of breast cancer. A systematic review of the literature was conducted using PubMed through April 2015. A multidisciplinary expert workgroup with expertise in primary care, gynecology, surgical oncology, medical oncology, radiation oncology, and nursing was formed and tasked with drafting the Breast Cancer Survivorship Care Guideline. A total of 1073 articles met inclusion criteria; and, after full text review, 237 were included as the evidence base. Patients should undergo regular surveillance for breast cancer recurrence, including evaluation with a cancer-related history and physical examination, and should be screened for new primary breast cancer. Data do not support performing routine laboratory tests or imaging tests in asymptomatic patients to evaluate for breast cancer recurrence. Primary care clinicians should counsel patients about the importance of maintaining a healthy lifestyle, monitor for post-treatment symptoms that can adversely affect quality of life, and monitor for adherence to endocrine therapy. Recommendations provided in this guideline are based on current evidence in the literature and expert consensus opinion. Most of the evidence is not sufficient to warrant a strong evidence-based recommendation. Recommendations on surveillance for breast cancer recurrence, screening for second primary cancers, assessment and management of physical and psychosocial long-term and late effects of breast cancer and its treatment, health promotion, and care coordination/practice implications are made.

Association of Variants in Candidate Genes with Lipid Profiles in Women with Early Breast Cancer on Adjuvant Aromatase Inhibitor Therapy

PURPOSE

Aromatase inhibitors can exert unfavorable effects on lipid profiles; however, previous studies have reported inconsistent results. We describe the association of single-nucleotide polymorphisms (SNP) in candidate genes with lipid profiles in women treated with adjuvant aromatase inhibitors.

EXPERIMENTAL DESIGN

We conducted a prospective observational study to test the associations between SNPs in candidate genes in estrogen signaling and aromatase inhibitor metabolism pathways with fasting lipid profiles during the first 3 months of aromatase inhibitor therapy in postmenopausal women with early breast cancer randomized to adjuvant letrozole or exemestane. We performed genetic association analysis and multivariable linear regressions using dominant, recessive, and additive models.

RESULTS

A total of 303 women had complete genetic and lipid data and were evaluable for analysis. In letrozole-treated patients, SNPs in CYP19A1, including rs4646, rs10046, rs700518, rs749292, rs2289106, rs3759811, and rs4775936 were significantly associated with decreases in triglycerides by 20.2 mg/dL and 39.3 mg/dL (P < 0.00053), respectively, and with variable changes in high-density lipoprotein (HDL-C) from decreases by 4.2 mg/dL to increases by 9.8 mg/dL (P < 0.00053).

CONCLUSIONS

Variants in CYP19A1 are associated with decreases in triglycerides and variable changes in HDL-C in postmenopausal women on adjuvant aromatase inhibitors. Future studies are needed to validate these findings, and to identify breast cancer survivors who are at higher risk for cardiovascular disease with aromatase inhibitor therapy.

Comparative study on individual aromatase inhibitors on cardiovascular safety profile: a network meta-analysis

The third-generation aromatase inhibitors (AIs: anastrozole, letrozole, and exemestane) have now become standard adjuvant endocrine treatment for postmenopausal estrogen receptor-positive breast cancer complementing chemotherapy and surgery. Because of the absence of direct head-to-head comparisons of these AIs, an indirect comparison is needed for individual treatment choice. In this network systemic assessment, the cardiovascular (CV) side effects in using anastrozole, letrozole, and exemestane based on original studies on AIs vs placebo or tamoxifen were compared. We integrated all available direct and indirect evidences. The odds ratio (OR) of severe CV events for indirect comparisons between exemestane and anastrozole was 1.41 (95% confidence interval [CI] =0.49–2.78), letrozole and anastrozole was 1.80 (95% CI =0.40–3.92), and letrozole and exemestane was 1.46 (95% CI =0.34–3.4). OR of subgroup risk for AIs and tamoxifen were all >1 except for thrombolism risk subgroup. The results showed that the total and severe CV risk ranking is letrozole, exemestane, and anastrozole in descending order. None of the AIs showed advantages in CV events than tamoxifen except for thromboembolism event incidence.

Safety of aromatase inhibitor therapy in breast cancer

INTRODUCTION

Aromatase inhibitor (AI) therapy is the current preferred choice of endocrine therapy in postmenopausal estrogen receptor-positive breast cancer patients thanks to their improved effectiveness compared to tamoxifen. Despite the absence of increased endometrial pathology and deep venous thrombosis seen in tamoxifen-users, the safety profile of AIs consists of a variety of bothersome side effects negatively influencing daily functioning.

AREAS COVERED

Besides the well-known adverse effects on joints and bone and the vasomotor system, more neglected and latent toxicity like cognitive problems and vulvovaginal atrophy will be discussed. Concern has been raised in terms of increased risk of fractures and cardiovascular events with chronic AI use.

EXPERT OPINION

Placebo-controlled long-term studies carefully monitoring these adverse events, together with more extensive research in the etiologies, are warranted.

Coadministrating luteolin minimizes the side effects of the aromatase inhibitor letrozole

Aromatase inhibitors (AIs) have been used as adjuvant therapeutic agents for breast cancer. Their adverse side effect on blood lipid is well documented. Some natural compounds have been shown to be potential AIs. In the present study, we compared the efficacy of the flavonoid luteolin to the clinically approved AI letrozole (Femara; Novartis Pharmaceuticals, East Hanover, NJ) in a cell and a mouse model. In the in vitro experimental results for aromatase inhibition, the Ki values of luteolin and letrozole were estimated to be 2.44 µM and 0.41 nM, respectively. Both letrozole and luteolin appeared to be competitive inhibitors. Subsequently, an animal model was used for the comparison. Aromatase-expressing MCF-7 cells were transplanted into ovariectomized athymic mice. Luteolin was given by mouth at 5, 20, and 50 mg/kg, whereas letrozole was administered by intravenous injection. Similar to letrozole, luteolin administration reduced plasma estrogen concentrations and suppressed the xenograft proliferation. The regulation of cell cycle and apoptotic proteins-such as a decrease in the expression of Bcl-xL, cyclin-A/D1/E, CDK2/4, and increase in that of Bax-was about the same in both treatments. The most significant disparity was on blood lipids. In contrast to letrozole, luteolin increased fasting plasma high-density lipoprotein concentrations and produced a desirable blood lipid profile. These results suggested that the flavonoid could be a coadjuvant therapeutic agent without impairing the action of AIs.

Lipid profiles within the SABRE trial of anastrozole with and without risedronate

Lipid profiles in women with early breast cancer receiving anastrozole with or without risedronate were examined within an international Phase III/IV study to assess for possible treatment related changes. Postmenopausal women with hormone receptor-positive breast cancer were assigned to 1 of 3 strata by risk of fragility fracture. Patients with the highest risk for fracture received anastrozole plus risedronate (A + R). Moderate-risk patients were randomized in a double-blind manner to A + R or anastrozole and placebo (A + P). Lower-risk patients received anastrozole (A) alone. Serial fasting blood samples were assessed for changes in lipid parameters relative to baseline after 12 months of treatment with anastrozole with or without risedronate. Samples were centrally analyzed for low-density lipoprotein cholesterol (LDL-cholesterol), high-density lipoprotein (HDL) cholesterol, total cholesterol (TC) and triglycerides (TG). Analysis was performed as primary analysis population for lipids (A plus A + P), lipid intention to treat population and secondary population (A + R). Of the 119 patients treated with A plus A + P, there were 66 patients eligible for inclusion in the primary analysis population. Of the 115 patients treated with secondary population (A + R) there were 65 patients eligible for lipid profiling. For LDL-cholesterol, HDL-cholesterol, TC and TG there were no significant changes between the baseline and 12 months assessments to suggest that any of these therapies have a negative impact on the lipid profile. In this study of postmenopausal women with early breast cancer receiving adjuvant anastrozole with or without risedronate, there was no adverse effect on LDL-cholesterol, HDL-cholesterol, TC or TG values over the 12 months monitoring period.