The influence of letrozole on serum lipid concentrations in postmenopausal women with primary breast cancer who have completed 5 years of adjuvant tamoxifen (NCIC CTG MA.17L)

Estrogen deprivation effects of endocrine therapy in breast cancer patients: Incidence, management and outcome

Endocrine therapy is one of the standard adjuvant treatments to reduce the risk of recurrence and mortality in patients with hormone receptor positive early breast cancer. Despite its proven efficacy, ET side effects, which persist over time even if low grade, may deteriorate quality of life. During follow-up visits, emphasis is generally placed on the risk of disease recurrence, while the topic of ET side effects is commonly neglected and discussed only briefly. This could lead to poor adherence to therapy and early treatment discontinuation, resulting in worse survival outcomes. The aim of this review is to provide an overview of the available evidence on the incidence and reporting of ET-related side effects (including vasomotor symptoms, musculoskeletal disorders and genitourinary syndrome of menopause, as well as fatigue, psychological and ocular disorders, dysmetabolic effects and loss of bone density) and of the pharmacological and non-pharmacological strategies available to mitigate symptom burden.

Association of serum lipid levels and clinical outcomes in early breast cancer patients

Background

The association between dyslipidaemia and breast cancer remains controversial, especially regarding the dynamic changes in lipid levels.

Objectives

This study aimed to elucidate the role of serum lipid levels and the changes in disease outcomes in patients with breast cancer.

Methods

The lipid profiles of patients with breast cancer who underwent surgery between 2013 and 2017 were retrospectively reviewed. The lipid profiles comprised triglyceride (TG), total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein. Serum lipid levels were categorized into three groups based on the tertiles. The Wilcoxon test was used to compare changes in serum lipid levels during follow-up. Hazard ratios (HRs) for survival outcomes were estimated using a multivariate Cox regression analysis.

Results

A total of 3499 women diagnosed with nonmetastatic invasive breast cancer were included in this study, with a median follow-up of 60.4 months. We confirmed that each 1-tertile increased TG at baseline [HR = 1.19, 95% confidence interval (CI) 1.02-1.39] and 1-year follow-up (HR = 1.46, 95% CI 1.07-1.98) led to worse relapse-free survival (RFS). A lower risk of disease relapse was observed with each 1-tertile upregulation in HDL at 1-year follow-up (HR = 0.72, 95% CI 0.56-0.92). Receiving systemic therapies tends to induce an elevation in plasma lipid levels 1 year after surgery, especially in terms of TG. Regarding the prognostic value of dynamic changes in lipid levels, patients with sustained high levels of TG had poorer RFS (HR = 1.90, 95% CI 1.16-3.11), whereas maintaining high levels of HDL led to better survival (HR = 0.60, 95% CI 0.37-0.97).

Conclusion

High TG at baseline and during follow-up was associated with worse disease outcome in early breast cancer patients. Systemic treatment would lead to an elevation of serum lipid levels. Patients with sustained high HDL level at 1-year follow-up after surgery had a superior prognosis, warranting further clinical evaluation.

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.

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.

Preventing late recurrence in hormone receptor-positive early breast cancer: a review

Late recurrences are a key challenge for patients with early-stage oestrogen receptor-positive breast cancer, with the risk of disease relapse continuing steadily from 5 to more than 20 years after diagnosis. Five years of adjuvant endocrine therapy with tamoxifen or an aromatase inhibitor was shown many years ago to improve survival. More recently, the trials of extended adjuvant endocrine therapy for more than 5 years have shown a further small gain, but with an associated small risk of increased long-term toxicity including bone loss, cardiovascular impairment and impaired quality of life. This review describes the efficacy and safety of extended endocrine therapy, the optimal selection criteria for patient benefit and the potential for novel agents to improve long-term outcomes.

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.

Association Between Aromatase Inhibitors and Myocardial Infarction Morbidity in Women With Breast Cancer: A Meta-Analysis of Observational Studies

BACKGROUND

The cardiovascular toxicity of aromatase inhibitors (AIs) for women with estrogen receptor-positive breast cancer is controversial. We aimed to evaluate the association between AIs and the risk of myocardial infarction (MI) in women with estrogen receptor-positive breast cancer based on real-world studies.

METHOD

PubMed, Embase, and Cochrane Library were searched to identify studies that estimated the association between MI risk and AIs. A random-effects model was used to evaluate the hazard ratio (HR) and 95% confidence intervals (CIs) of the predefined outcomes.

RESULTS

A total of 134 476 patients from eight cohort studies were enrolled in our analysis. For MI incidence, no significant difference was found between the users of AIs and non-users (HR: .98, 95% CI: .83-1.17). The subgroup analysis of patients without a history of cardiovascular disease (CVD) suggested a reduced risk of MI (HR: .86, 95% CI: .77-.96). No significant difference was found for ischemic stroke (HR: .93, 95% CI: .82-1.07) and heart failure (HR: 1.24, 95% CI: .92-1.66) between the two groups.

CONCLUSION

Based on real-world data, AIs may be a safe treatment route for patients with estrogen receptor-positive breast cancer and those with a history of CVD. AIs caused a major decrease in MI in patients without CVD history. However, more in-depth investigations are needed to explore the association between AI use and the incidence of MI in the treatment of estrogen receptor-positive breast cancer.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Ficus deltoidea ameliorates biochemical, hormonal, and histomorphometric changes in letrozole-induced polycystic ovarian syndrome rats

BACKGROUND

Insulin resistance and hormonal imbalances are key features in the pathophysiology of polycystic ovarian syndrome (PCOS). We have previously shown that Ficus deltoidea var. deltoidea Jack (Moraceae) can improve insulin sensitivity and hormonal profile in PCOS female rats. However, biological characteristics underpinning the therapeutic effects of F. deltoidea for treating PCOS remain to be clarified. This study aims to investigate the biochemical, hormonal, and histomorphometric changes in letrozole (LTZ)-induced PCOS female rats following treatment with F. deltoidea.

METHODS

PCOS was induced in rats except for normal control by administering LTZ at 1 mg/kg/day for 21 days. Methanolic extract of F. deltoidea leaf was then orally administered to the PCOS rats at the dose of 250, 500, or 1000 mg/kg/day, respectively for 15 consecutive days. Lipid profile was measured enzymatically in serum. The circulating concentrations of reproductive hormone and antioxidant enzymes were determined by ELISA assays. Ovarian and uterus histomorphometric changes were further observed by hematoxylin and eosin (H&E) staining.

RESULTS

The results showed that treatment with F. deltoidea at the dose of 500 and 1000 mg/kg/day reduced insulin resistance, obesity indices, total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL), malondialdehyde (MDA), testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) to near-normal levels in PCOS rats. The levels of high-density lipoprotein cholesterol (HDL), estrogen, and superoxide dismutase (SOD) are also similar to those observed in normal control rats. Histomorphometric measurements confirmed that F. deltoidea increased the corpus luteum number and the endometrial thickness.

CONCLUSIONS

F. deltoidea can reverse PCOS symptoms in female rats by improving insulin sensitivity, antioxidant activities, hormonal imbalance, and histological changes. These findings suggest the potential use of F. deltoidea as an adjuvant agent in the treatment program of PCOS.

Does letrozole treatment have favorable effects on the lipid profile? A systematic review and meta-analysis of randomized clinical trials

As an aromatase inhibitor, letrozole reduces estrogen levels, affecting lipid indices because of the positive role of estrogens in modulating lipoproteins and lipids. Thus, our aim was to meta-analyze data regarding letrozole administration and its effects on the traditional lipid profile. A systematic review and meta-analysis of randomized clinical trials (RCTs) were performed based on the PRISMA guidelines. Web of Science, Scopus, PubMed/Medline, and EMBASE databases were searched until February 11, 2021. From 341 potentially relevant publications, 8 RCTs were selected. All studies used 2.5 mg/d of letrozole. Total cholesterol changed significantly by -6.28 mg/dL (95% CI: -8.73, -3.84, P < 0.001) and HDL-C by -4.40 mg/dL (95% CI: -5.30 to -3.50, p < 0.001) in letrozole group when compared to the control group. Taking into account this comparison between groups, in contrast, LDL-C (WMD: -2.50 mg/dL, 95% CI: -9.94, 4.93, p = 0.510) and triglycerides (WMD: -0.89 mg/dL, 95% CI: -6.87 to 5.07, p = 0.768) did not alter. In conclusion, letrozole administration decreased the concentrations of HDL-C and tocal cholesterol, but not of triglycerides and LDL-C.

Engagement of phytoestrogens in breast cancer suppression: Structural classification and mechanistic approach

Cancer is the world's devastating disease, and breast cancer is the most common reason for the death of women worldwide. Many synthetic drugs and medications are provided with their beneficial actions, but all of these have side effects and resistance problems. Natural remedies are coming forward to overcome the disadvantages of synthetic drugs. Among the natural categories, phytoestrogens having a structural similarity of mammalian oestradiol proves its benefit with various mechanisms not only in the treatment of breast cancer but even to prevent the occurrence of postmenopausal symptoms. Phytoestrogens are plant-derived compounds that were utilized in ancient medications and traditional knowledge for its sex hormone properties. Phytoestrogens exert pleiotropic effects on cellular signalling and show effects on estrogen-dependent diseases. However, because of activation/inhibition of steroid hormonal receptor ER-α or ER-β, these compounds induce or inhibit steroid hormonal (estrogen) action and, therefore, have the potential to disrupt hormone (estrogen) signalling pathway. In this review, we have discussed and summarize the effect of certain phytoestrogens and their possible mechanisms that can substantiate advantageous benefits for the treatment of post-menopausal symptoms as well as for breast cancer.

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.

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

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.

Cancer Survivorship in Primary Care

With the early detection of cancer and improvement in cancer therapy, the number of cancer survivors is rapidly increasing. This number is expected to reach 2 million by the end of 2019. Cancer survivors struggle with not only cancer-related health problems but also diverse acute and chronic diseases. These health issues make cancer survivorship more complex, and proper care coordination is necessary. This study aimed to summarize the definition of cancer experience and management of cancer survivors, specifically focused on gastric, colorectal, lung, breast, thyroid, prostate, and cervical cancers. Furthermore, it aimed to discuss the role of primary care in cancer survivorship and survivorship care models and the National Policy for Cancer Survivors and Future Challenges.

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.

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.

Aromatase inhibitor use is a risk factor of carotid plaque presence in endocrine-responsive breast cancer patients

BACKGROUND/AIMS

The aromatase inhibitors (AIs) are well known anti-hormonal therapy in endocrine-responsive breast cancer patients. It can lead to dyslipidemia and be the risk factor of cardiovascular disease due to low estrogen level. However, some recent studies comparing AIs with placebo have shown controversial results. The aim of this study was to investigate lipid profiles, measurement of carotid intima-media thickness (IMT) and the presence of plaque among endocrine-responsive breast cancer treated with AIs compared to ones that were not treated with AIs.

METHODS

A total of 85 postmenopausal women, who underwent breast cancer surgery during the age of 50 to 64 without history of statin use were included. There were 42 patients who were treated with AIs over 1 year (group 1) and 43 patients without AIs use (group 2). Serum total cholesterol, high density lipoprotein cholesterol, triglycerides, fasting blood glucose, carotid IMT, and presence of plaque were assessed.

RESULTS

The baseline characteristics were similar between two groups and there was no significant difference in carotid IMT irrespective of AIs administration. However, ultrasonographic evaluation of carotid artery revealed that the presence of plaque in AI users was significantly higher than in non-AI users (66.7% vs. 41.9%, p = 0.02; odds ratio, 4.21 in adjusted model; p = 0.01). History of diabetes was also the significant risk factor for the plaque formation.

CONCLUSION

There was no significant difference in lipid profile itself between two groups, but more importantly the presence of the plaque was much higher indicating possible detrimental effect of AI on cardiovascular system.

Acute Pancreatitis Caused by Tamoxifen-Induced Severe Hypertriglyceridemia After 4 Years of Tamoxifen Use

We report a case of a 55-year-old woman with hypertension and diabetes mellitus, who took tamoxifen for the past 4 years. She presented with acute pancreatitis caused by markedly elevated serum triglycerides (3,883 mg/dL). Tamoxifen is known to cause a mild increase in serum triglycerides, but it rarely increases to such high levels to cause acute pancreatitis. The patient recovered well, and tamoxifen was switched to letrozole. It is crucial to monitor serum lipids up to 4 years and beyond for patients on tamoxifen, particularly in patients with known dyslipidemia or diabetes mellitus.

Cancer survivors: An expanding population with an increased cardiometabolic risk

In the last decades the survival rate of patients diagnosed with cancer - both in childhood and adulthood - significantly improved, leading to a growing number of cancer survivors (CS) within general population. Despite the better survival rate related to the cancer diagnosis, CS show increased mortality and morbidity if compared to non-cancer population, due to the occurrence of health conditions categorized as late effects of previous anticancer treatments. Cardiovascular (CV) diseases are one of the main responsible for this increased morbidity of CS. Besides the direct injury that both chemotherapy and radiotherapy can produce to CV system, in recent years the role of metabolic syndrome in the pathogenesis of CV diseases in CS is emerging. The relationship between anticancer treatments and the development of metabolic alterations is crucial to understand and manage the cardiometabolic risk in CS. The aim of this manuscript is to review the pathophysiological and clinical features of CV risk factors in CS, exploring in more detail certain subgroups of CS (breast cancer, transplanted patients as well as lymphoma survivors) that show peculiar clinical aspects and are burdened by a greater CV risk.

Assessment of Quality of Life and Safety in Postmenopausal Breast Cancer Patients Receiving Letrozole as an Early Adjuvant Treatment

Purpose

There are few reports from Asian countries about the long-term results of aromatase inhibitor adjuvant treatment for breast cancer. This observational study aimed to evaluate the long-term effects of letrozole in postmenopausal Korean women with operable breast cancer.

Methods

Self-reported quality of life (QoL) scores were serially assessed for 3 years during adjuvant letrozole treatment using the Korean version of the Functional Assessment of Cancer Therapy-Breast questionnaires (version 3). Changes in bone mineral density (BMD) and serum cholesterol levels were also examined.

Results

All 897 patients received the documented informed consent form and completed a baseline questionnaire before treatment. Adjuvant chemotherapy was administered to 684 (76.3%) subjects, and 410 (45.7%) and 396 (44.1%) patients had stage I and II breast cancer, respectively. Each patient completed questionnaires at 3, 6, 12, 18, 24, 30, and 36 months after enrollment. Of 897 patients, 749 (83.5%) completed the study. The dropout rate was 16.5%. The serial trial outcome index, the sum of the physical and functional well-being subscales, increased gradually and significantly from baseline during letrozole treatment (p<0.001). The mean serum cholesterol level increased significantly from 199 to 205 after 36 months (p=0.042). The mean BMD significantly decreased from −0.39 at baseline to −0.87 after 36 months (p<0.001).

Conclusion

QoL gradually improved during letrozole treatment. BMD and serum cholesterol level changes were similar to those in Western countries, indicating that adjuvant letrozole treatment is well tolerated in Korean women, with minimal ethnic variation.

Cardiotoxicity of aromatase inhibitors and tamoxifen in postmenopausal women with breast cancer: a systematic review and meta-analysis of randomized controlled trials

Background

Aromatase inhibitors (AIs) have been associated with cardiovascular disease in adjuvant randomized controlled trials (RCTs) comparing these drugs to tamoxifen. However, it is unclear whether this risk is real or due to cardioprotective effects of tamoxifen. To address this question, we conducted a systematic review and meta-analysis of all RCTs of AIs and tamoxifen in adjuvant and extended adjuvant setting.

Patients and methods

We searched PubMed, Embase (OVID), Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov from inception to June 2016 for all RCTs comparing cardiovascular and cerebrovascular safety of AIs to tamoxifen, AIs to placebo or no-treatment, or tamoxifen to placebo or no-treatment in the adjuvant or extended adjuvant setting. Relative risks (RRs) were pooled using DerSimonian and Laird random-effects models with analyses stratified by RCT design.

Results

A total of 19 RCTs were included in the meta-analysis (n  =  62 345). In the adjuvant setting, AIs were associated with a 19% (RR: 1.19, 95% confidence interval [CI]: 1.07-1.34) increased risk of cardiovascular events compared with tamoxifen. AIs were not associated with an increased risk compared with placebo in the extended-adjuvant setting (RR: 1.01, 95% CI: 0.85-1.20). In the adjuvant setting, tamoxifen was associated with a 33% (RR: 0.67, 95% CI: 0.45-0.98) decreased risk compared with placebo or no-treatment. The results from extended adjuvant RCTs comparing tamoxifen to placebo were inconclusive but suggestive of a small protective effect (RR: 0.91, 95% CI: 0.77-1.07).

Conclusions

The increased risk of cardiovascular events with AIs relative to tamoxifen is likely the result of cardioprotective effects of the latter. This new evidence should be considered when assessing the benefits and risks of AIs in the treatment of breast cancer.

Need for Weight Management among Postmenopausal Early Breast Cancer Patients Receiving Adjuvant Endocrine Therapy

Increasingly effective adjuvant therapies mean that the prognosis for postmenopausal women with breast cancer has never been better. Weight problems are common among breast cancer patients and worsen due to the impact of diagnosis and treatment. Recent studies have linked excess weight with the risk of recurrence of breast cancer among premenopausal women. While general obesity (body mass index) does not appear to influence the already much improved prognosis for postmenopausal women, there is some evidence that limiting central obesity and improving insulin resistance may improve survival. The focus of attention for postmenopausal breast cancer survivors is also shifting to consider the mortality and morbidity from other weight-related cancers and noncancer causes, such as cardiovascular disease, making weight control a potentially important adjunct to endocrine therapy. This paper outlines the rationale and optimal design for effective weight management strategies among postmenopausal breast cancer patients receiving endocrine therapy.

Tamoxifen-induced hypertriglyceridemia causing acute pancreatitis

Tamoxifen has both antagonistic and agonistic tissue-specific actions. It can have a paradoxical estrogenic effect on lipid metabolism resulting in elevated triglyceride and chylomicron levels. This can cause life-threatening complications like acute pancreatitis. To our knowledge, very few cases of tamoxifen-induced pancreatitis have been reported in the literature. We report a case of severe hypertriglyceridemia and acute pancreatitis following tamoxifen use. A 50-year-old diabetic lady was on tamoxifen (20mg/day) hormonal therapy for breast cancer. Within 3 months of starting therapy, she developed hypertriglyceridemia and acute pancreatitis. Laboratory values include: Serum amylase 778 IU/L, total cholesterol 785 mg/dL, triglycerides 4568 mg/dL and high-density lipoproteins (HDL) 12 mg/dL. Tamoxifen was substituted with letrozole and atorvastatin started. There was a prompt reversal of the adverse effects. Effects on lipid profile must be considered while initiating tamoxifen in predisposed individuals as the consequences are life threatening.

Double-Blind, Randomized Trial of Alternative Letrozole Dosing Regimens in Postmenopausal Women with Increased Breast Cancer Risk

Aromatase inhibitors (AI) profoundly suppress estrogen levels in postmenopausal women and are effective in breast cancer prevention among high-risk postmenopausal women. Unfortunately, AI treatment is associated with undesirable side effects that limit patient acceptance for primary prevention of breast cancer. A double-blind, randomized trial was conducted to determine whether low and intermittent doses of letrozole can achieve effective estrogen suppression with a more favorable side-effect profile. Overall, 112 postmenopausal women at increased risk for breast cancer were randomized to receive letrozole at 2.5 mg once daily (QD, standard dose arm), 2.5 mg every Monday, Wednesday, and Friday (Q-MWF), 1.0 mg Q-MWF, or 0.25 mg Q-MWF for 24 weeks. Primary endpoint was suppression in serum estradiol levels at the end of letrozole intervention. Secondary endpoints included changes in serum estrone, testosterone, C-telopeptide (marker of bone resorption), lipid profile, and quality-of-life measures (QoL) following treatment. Significant estrogen suppression was observed in all dose arms with an average of 75% to 78% and 86% to 93% reduction in serum estradiol and estrone levels, respectively. There were no differences among dose arms with respect to changes in C-telopeptide levels, lipid profile, adverse events (AE), or QoL measures. We conclude that low and intermittent doses of letrozole are not inferior to standard dose in estrogen suppression and resulted in a similar side-effect profile compared with standard dose. Further studies are needed to determine the feasibility of selecting an effective AI dosing schedule with better tolerability.

The impact of Anastrazole and Letrozole on the metabolic profile in an experimental animal model

Anastrazole and Letrozole are used as endocrine therapy for breast cancer patients. Previous studies suggested a possible association with metabolic and liver adverse effects. Their results are conflicting. Fifty-five 4-week-old female Wistar rats were allocated in 4 groups 1) ovariectomy control (OC), 2) ovariectomy-Anastrazole (OA) 3) ovariectomy -Letrozole (OL), 4) control. Serum glucose, cholesterol, triglycerides, HDL-c and LDL-c were measured at baseline, 2 and 4 months. At the end, the animals' liver were dissected for pathology. At 4 months, total cholesterol differed among the OC and OL groups (p = 0.15) and the control and OL groups (p = 0.12). LDL-C differed between the control and OC groups (p = 0.015) as well as between the control and OA (p =0 .015) and OL groups (p = 0.002). OC group triglycerides, differed from those of the OL group (p =0 .002) and the control group (p = 0.007). The OA also significantly differed from the OL (p = 0.50). Liver pathology analysis revealed differences among groups with favored mild steatosis and ballooning. Anastrazole and Letrozole seem to negatively influence the lipid profile in our experimental model. This information should be taken in caution by medical oncologists when addressing patients with altered lipid metabolism.

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.

Racial differences in depressive symptoms and self-rated health among breast cancer survivors on aromatase inhibitor therapy

The goal of this survey-based study was to examine whether aromatase inhibitor (AI) therapy was associated with depressive symptoms and self-rated health among Black and White breast cancer survivors (N = 761). Results showed that among Black, but not White, breast cancer survivors current AI therapy was associated with a significant increase in the odds of both depressive symptoms (OR 3.59; 95% CI 1.01, 13.00) and poorer self-rated health (OR 3.16; 95% CI 1.06, 9.46). Presence of pain was significantly associated with increased odds of both outcomes among both groups. The findings underscore the importance of addressing not only physical but mental health among breast cancer survivors on AIs, especially those of Black race.

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.

Adverse effects of endocrine therapy in breast cancer: single institute experience

AIM OF THE STUDY

The main purpose of this study is to assess the known adverse effects of adjuvant endocrine therapy for non-metastatic breast cancer patients and to present our single center experience with light of literature.

MATERIAL AND METHODS

The breast cancer patients treated with adjuvant radiotherapy in Medical School of Ege University between January 2007 and December 2009 were evaluated for this trial after obtaining their acceptance. Vital findings, bone mineral densitometry, endometrium thickness measured with trans-vaginal ultrasonography, biochemical results including liver function tests and blood lipid profile (total cholesterol, HDL, LDL, VLDL, triglyceride) were recorded for each controls. Socio-demographic data, financial statuses, medical history, co-morbid diseases were obtained from first controls. Patients were followed without any local recurrence and distant metastases until June 2011.

RESULTS

Endometrium thickness was not seen in AI using patients. As compared with tamoxifen group, lack of thickness in AI group was statistically significant (p = 0.000). When compared the values before AI, the number of patients who had osteoporosis was gradually increasing. The decrease was seen in the number of patients with osteopenia. The number of patients with normal lipid profile was gradually increasing up to the second evaluation for tamoxifen group (p = 0.000). On the other hand, the number of patients with hyperlipidemia was increasing for AIs group in follow-up period statistically (p = 0.006).

CONCLUSIONS

With the aid of careful patient follow and effective disease management strategies, the negative effect over the QoL can be minimized and also the greatest benefit from endocrine therapy can be obtained.

Extended adjuvant therapy with letrozole: reducing the risk of recurrence

Patients with all stages of primary breast cancer are at continuing risk of relapse following 5 years of adjuvant tamoxifen therapy, even in the absence of lymph node involvement. Tamoxifen has been the standard therapy for reducing risk of recurrence, although more than 50% of relapses and deaths occur after completion of tamoxifen. Tamoxifen use is associated with an increased risk of serious side effects, and extended use beyond 5 years may have a negative impact on disease-free survival. Extended adjuvant letrozole therapy confers a significant benefit in relapse-free survival. The approval of letrozole for this indication in the USA and in many European countries introduces a new, safe and effective treatment for disease-free patients seeking to reduce their long-term risk of recurrence.

Effects of adjuvant aromatase inhibitor therapy on lipid profiles

How aromatase inhibitors affect lipids is of great interest. Compared with tamoxifen, adjuvant anastrozole and letrozole are associated with increased incidences of hypercholesterolemia, while similar data are lacking for exemestane in the adjuvant setting. No significant differences in lipid profiles occurred with extended adjuvant exemestane compared with placebo, but total cholesterol and low-density lipoprotein levels increased significantly above baseline in both groups over 6 months. Likewise, no significant differences in hypercholesterolemia rates occurred between extended adjuvant letrozole and placebo. A lipid substudy further confirmed that letrozole did not significantly alter serum lipids for 36 months compared with placebo. Thus, although aromatase inhibitors lack the lipid-lowering properties of tamoxifen, no significant worsening of lipid levels occurs with their use. Patients would benefit from lifestyle changes and routine monitoring of serum lipids. Breast cancer therapy trials often report serum lipid parameters, but assessing the quality and overall significance of the data can be difficult. Methodology of data collection varies among trials and the concomitant use of lipid-modifying medication is often not reported. This review discusses the current understanding of the influence of lipid levels on cardiovascular risk in women and presents key findings on the effects of adjuvant aromatase inhibitor therapy on lipid profiles.

Special considerations in early-stage breast cancer patients and survivors

Long-term outcomes for early-stage breast cancer have continued to improve, and more patients are becoming long-term survivors. In addition to patients' concern about risk of developing recurrent disease, they are also concerned about potential toxicities of treatment. Current guidelines for long-term follow-up are reviewed. Potential toxicities of tamoxifen and aromatase inhibitors are reviewed. Management of menopausal symptoms, cancer-related fatigue, and cognitive function is discussed.

Aromatase inhibition 2013: clinical state of the art and questions that remain to be solved

Following their successful implementation for the treatment of metastatic breast cancer, the 'third-generation' aromatase inhibitors (anastrozole, letrozole, and exemestane) have now become standard adjuvant endocrine treatment for postmenopausal estrogen receptor-positive breast cancers. These drugs are characterized by potent aromatase inhibition, causing >98% inhibition of estrogen synthesis in vivo. A recent meta-analysis found no difference in anti-tumor efficacy between these three compounds. As of today, aromatase inhibitor monotherapy and sequential treatment using tamoxifen followed by an aromatase inhibitor for a total of 5 years are considered equipotent treatment options. However, current trials are addressing the potential benefit of extending treatment duration beyond 5 years. Regarding side effects, aromatase inhibitors are not found associated with enhanced risk of cardiovascular disease, and enhanced bone loss is prevented by adding bisphosphonates in concert for those at danger of developing osteoporosis. However, arthralgia and carpal tunnel syndrome preclude drug administration among a few patients. While recent findings have questioned the use of aromatase inhibitors among overweight and, in particular, obese patients, this problem seems to focus on premenopausal patients treated with an aromatase inhibitor and an LH-RH analog in concert, questioning the efficacy of LH-RH analogs rather than aromatase inhibitors among overweight patients. Finally, recent findings revealing a benefit from adding the mTOR inhibitor everolimus to endocrine treatment indicate targeted therapy against defined growth factor pathways to be a way forward, by reversing acquired resistance to endocrine therapy.

Extended adjuvant endocrine therapy in hormone dependent breast cancer: the paradigm of the NCIC-CTG MA.17/BIG 1-97 trial

Early hormone-receptor-positive breast cancer is a chronic relapsing disease that can remain clinically silent for many years. The NCIC-CTG MA.17/BIG 1-97 trial randomized disease-free early breast cancer patients who had received five years of adjuvant tamoxifen to either letrozole or placebo and was the first to demonstrate a benefit with extended endocrine therapy. MA.17/BIG 1-97 was stopped at the first interim analysis because disease free survival was strongly prolonged in the letrozole arm. Subsequent subset analyses and longer follow up have shown that this therapy improved survival across all groups, particularly among women with node-positive disease and those that were pre-menopausal at time of study enrolment. The MA.17/BIG 1-97 study should be considered a paradigm for extended adjuvant endocrine therapy in hormone-receptor-positive early breast cancer.

Putting the cardiovascular safety of aromatase inhibitors in patients with early breast cancer into perspective: a systematic review of the literature

In the adjuvant setting, the third-generation aromatase inhibitors (AIs) anastrozole, letrozole and exemestane are recommended at some point during treatment, either in the upfront, switch after tamoxifen or extended treatment setting after tamoxifen in postmenopausal patients with hormone receptor-positive early breast cancer. AIs have demonstrated superior disease-free survival and overall benefit-to-risk profiles compared with tamoxifen. Potential adverse events, including cardiovascular (CV) side effects, should be considered in the long-term management of patients undergoing treatment with AIs. AIs reduce estrogen levels by inhibiting the aromatase enzyme, thus reducing the levels of circulating estrogen. This further reduction in estrogen levels may potentially increase the risk of developing CV disease. This systematic review evaluated published clinical data for changes in plasma lipoproteins and ischaemic CV events during adjuvant therapy with AIs in patients with hormone receptor-positive early breast cancer. The electronic databases MEDLINE, EMBASE, Derwent Drug File and BIOSIS were searched to identify English-language articles published from January 1998 to 15 April 2011 that reported data on AIs and plasma lipoproteins and/or ischaemic CV events. Overall, available data did not show any definitive patterns or suggest an unfavourable effect of AIs on plasma lipoproteins from baseline to follow-up assessment in patients with hormone receptor-positive early breast cancer. Changes that occurred in plasma lipoproteins were observed soon after initiation of AI therapy and generally remained stable throughout the studies. Available data do not support a substantial risk of ischaemic CV events associated with adjuvant AI therapy; however, studies with longer follow-up are required to better characterize the CV profile of AIs.

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

Effects of aromatase inhibitor (AI) therapy on the plasma lipid profile are not clear. Here the authors describe changes in fasting lipids (total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL], and triglycerides) before and after 3 months of exemestane or letrozole treatment. HDL was reduced in the entire cohort (P < .001) and in the exemestane group (P < .001) but unchanged in the letrozole group (P = .169). LDL was increased in the entire cohort (P = .005) and in the letrozole group (P = .002) but unchanged in the exemestane group (P = .361). This effect was at least partially attributable to washout of tamoxifen as only patients with prior use of tamoxifen experienced a significant increase in LDL. Baseline HDL was an independent predictor of the change in HDL (r(2) = -0.128, P < .001), and prior tamoxifen use was associated with greater increases in LDL (r(2) = 0.057, P < .001). Use of lipid-altering medications did not protect against the exemestane-induced drop in HDL or the increase in LDL observed in women with prior use of tamoxifen taking letrozole. In conclusion, AI treatment and/or washout of tamoxifen induced detrimental changes in the lipid profile of postmenopausal women with breast cancer.

An overview of letrozole in postmenopausal women with hormone-responsive breast cancer

Third-generation aromatase inhibitors (AIs) have proven to be superior to tamoxifen in terms of time to disease progression in patients with hormone receptor (HR) positive (HR+) status and, nowadays, are used in the adjuvant and neoadjuvant settings, and first-line therapy for advanced breast cancer. Letrozole is a third generation AI, as are anastrozole and exemestane. In the past, clinical studies had demonstrated that letrozole was effective as a second-line treatment of metastatic breast cancer. In this paper, pharmacokinetic and pharmacodynamic properties of letrozole are reviewed along with its activity in preclinical and clinical settings. Additionally, the results of important clinical trials such as Breast International Group (BIG) 1-98, which tested the optimal initial adjuvant endocrine treatment and the sequential therapy with letrozole and tamoxifen, MA-17 that evaluates the benefits of extended adjuvant therapy, and other important studies in advanced and neoadjuvant disease, are reviewed. Safety comparisons of treatments are also addressed. Interestingly, about 50% of human epidermal growth factor receptor 2-positive (HER2+) breast cancers are HR+. However, HER2 positivity is a marker of antiestrogen treatment resistance. Because of this, a dual treatment is a logical approach when both receptors are overexpressed. The combination of lapatinib and letrozole leads to a significant improvement in the overall disease outcome. Also, the combination of everolimus plus letrozole has been tested in this setting. In fact, the coadministration of both agents seems to increase the efficacy of letrozole in newly-diagnosed HR+ patients. Once resistance to sequential trastuzumab and AI as monotherapy has been found, trastuzumab and letrozole combined in HR+ and HER2+ patients with advanced breast cancer can overcome resistance to both drugs administered as single agents, according to recently reported results.

Long-term safety of aromatase inhibitors in the treatment of breast cancer

Following promising data for metastatic breast cancer in terms of efficacy and safety profile, third-generation aromatase inhibitors (AI), anastrozole, letrozole, and exemestane, underwent a full development in early setting. If recent results consistently show the superiority of these agents over tamoxifen, the therapeutic strategies of AIs in adjuvant setting are still debated. Beyond the choice of clinical strategy, the long duration of exposure to AI in adjuvant setting required a full determination of the long-term toxicity profile of these agents. While all three AIs have either favorable (decreased incidence of hot flashes, gynecologic and thromboembolic side-effects) or unfavorable (skeletal complications, arthralgia, musculoskeletal pain, sexual dysfunction) class adverse events, some variability between AIs has been reported in side-effects as well as gastrointestinal, urogenital, neurologic, and visual disturbances, confirming the lack of interchangeability between the three AIs. The overall therapeutic index of AIs appears today superior to that of tamoxifen with proven improved efficacy and better toxicity profile. This review will explore the results from the available adjuvant AIs trials with a particular emphasis on safety profiles, quality of life, and therapeutic index, helping to define the present role of AIs in the adjuvant management of postmenopausal patients with breast cancer.

Letrozole induces hepatotoxicity without causing oxidative stress: the protective effect of melatonin

AIM

The aim of this study was to determine the effects of letrozole (LTZ), an aromatase inhibitor (AI), and melatonin (MLT) on hepatic function and oxidative stress in female rats.

MATERIAL AND METHODS

A total of 32 female rats were divided equally into four groups (n = 8). Control group received saline (0.5 ml/day, oral gavage). LTZ was administered to rats by daily oral gavage at 1 mg/kg dose. LTZ + MLT group was given LTZ (1 mg/kg, oral gavage) plus MLT (0.5 mg/kg/day, s.c.). MLT group was given MLT (0.5 mg/kg/day) by s.c. injection. The activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) levels were measured in liver tissue. Total antioxidant capacity (TAC), total oxidant status (TOS), ALT, AST, GGT, ALP, LDH, bilirubin, BUN, creatinine, total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were assayed in serum samples.

RESULTS

The oxidative stress parameters did not differ between groups. LTZ administration increased hepatic function parameters such as AST, LDH, ALP, bilirubin and MLT improved the disturbances of hepatic function. LTZ caused minimal histological changes in liver tissue and MLT treatment reversed those dejenerations.

DISCUSSION

LTZ may cause hepatotoxicity without inducing oxidative stress and MLT restores hepatic activity.

A randomized, placebo-controlled trial (NCIC CTG MAP.2) examining the effects of exemestane on mammographic breast density, bone density, markers of bone metabolism and serum lipid levels in postmenopausal women

We hypothesized that exemestane (EXE) would reduce mammographic breast density and have unique effects on biomarkers of bone and lipid metabolism. Healthy postmenopausal women were randomized to EXE (25 mg daily) or placebo (PLAC) for 12 months and followed for a total of 24 months. The primary endpoint was change in percent breast density (PD) between the baseline and 12-month mammograms and secondary endpoints were changes in serum lipid levels, bone biomarkers, and bone mineral density (BMD). Ninety-eight women were randomized (49 to EXE; 49 to PLAC) and 65 had PD data at baseline and 12 months. Among women treated with EXE, PD was not significantly changed from baseline at 6, 12, or 24 months and was not different from PLAC. EXE was associated with significant percentage increase from baseline in N-telopeptide at 12 months compared with PLAC. No differences in percent change from baseline in BMD (lumbar spine and femoral neck) were observed between EXE and PLAC at either 12 or 24 months. Patients on EXE had a significantly larger percent decrease in total cholesterol than in the PLAC arm at 6 months and in HDL cholesterol at 3, 6, and 12 months. No significant differences in percent change in LDL or triglycerides were noted at any time point between the two treatment arms. EXE administered for 1 year to healthy postmenopausal women did not result in significant changes in mammographic density. A reversible increase in the bone resorption marker N-telopeptide without significant change in bone specific alkaline phosphatase or BMD during the 12 months treatment period and 1 year later was noted. Changes in lipid parameters on this trial were modest and reversible.

The potency and clinical efficacy of aromatase inhibitors across the breast cancer continuum

The strategy of using estrogen suppression to treat breast cancer led to the development of aromatase inhibitors, including the third-generation nonsteroidal compounds anastrozole and letrozole, and the steroidal compound exemestane. Aromatase inhibitors potently inhibit aromatase activity and also suppress estrogen levels in plasma and tissue. In clinical studies in postmenopausal women with breast cancer, third-generation aromatase inhibitors were shown superior to tamoxifen for the treatment of metastatic disease. Studies of adjuvant therapy with aromatase inhibitors include (i) head-to-head studies of 5 years of the aromatase inhibitor versus 5 years of tamoxifen monotherapy; (ii) sequential therapy of 2-3 years of tamoxifen followed by an aromatase inhibitor (or the opposite sequence) versus 5 years of tamoxifen monotherapy; (iii) extended therapy with an aromatase inhibitor after 5 years of tamoxifen; and (iv) sequential therapy with an aromatase inhibitor versus aromatase inhibitor monotherapy. Recent results from the Arimidex, Tamoxifen, Alone or in Combination and Breast International Group 1-98 trials advocate using an aromatase inhibitor upfront. This article examines the clinical data with aromatase inhibitors, following a brief summary of their pharmacology.