Efficacy of extended aromatase inhibitors for hormone-receptor-positive breast cancer: A literature-based meta-analysis of randomized trials

BACKGROUND

Endocrine treatment with Tamoxifen and aromatase inhibitors (AIs) is a staple in the management of hormone receptor positive breast cancer (HR + BC). It has become clear that HR + BC carries a consistent risk of relapse up to 15 years post-diagnosis. While increasing evidence supports the use of extended adjuvant Tamoxifen over 5 years, controversial data are available on the optimal duration of extended AIs adjuvant treatment. We performed a meta-analysis to assess the real impact of extended adjuvant therapy with AIs on disease-free survival (DFS).

METHODS

A literature-based meta-analysis of randomized controlled trials (RCTs) was undertaken. Relevant publications from PubMed, the Cochrane Library, and abstracts from American Society of Clinical Oncology (ASCO) and San Antonio Breast Cancer (SABCS) symposia were searched. Primary and secondary endpoints were Disease Free Survival (DFS) and overall survival (OS) respectively. A subgroup analysis was also performed to elucidate the impact of nodal involvement.

RESULTS

The pooled analysis revealed a significant increase in DFS in the extended AIs group (hazard ratio (HR): 0.78, 95% CI: 0.68-0.90; P = 0.0006). The subgroup analysis according to nodal status showed a greater DFS benefit with extended AIs in patients with positive nodes (HR = 0.67 versus 0.80). Our analysis also demonstrated no improvement in OS with extended AIs (HR = 0.99, 95%CI: 0.87-1.12; P = 0.84).

CONCLUSION

This work confirmed the efficacy of extended adjuvant treatment with AIs for HR + early breast cancer, with a 22% increase in DFS, but no impact on OS. Greater efficacy was observed in women with positive nodal status.

Effect of Aromatase Inhibitor Therapy on Sleep and Activity Patterns in Early-stage Breast Cancer

INTRODUCTION

Adherence to aromatase inhibitor (AI) therapy is poor, often because of treatment-emergent side effects, including musculoskeletal symptoms, fatigue, and insomnia. In the present analysis, we examined the sleep patterns and daytime function both objectively using actigraphy and subjectively using validated questionnaires in women initiating AI therapy.

PATIENTS AND METHODS

Postmenopausal women with stage 0-III hormone receptor-positive breast cancer who were initiating AI therapy were eligible. The patients wore actigraphy devices for 10 consecutive days and completed questionnaires at baseline before the initiation of AI and after 3 months of AI therapy. Associations between the baseline demographics and symptoms, changes in patient-reported outcomes and actigraphy measures from baseline to 3 months of AI therapy and discontinuation of AI therapy were examined using sign tests, logistic regression models, Spearman's correlation, and linear mixed models.

RESULTS

Forty-two patients (86%) completed the baseline assessments and 23 patients (47%) completed both the baseline and the 3-month assessments. Objectively measured daytime function as measured by total daytime activity decreased during the 3 months after starting AI (232,566 activity count vs. 204,205 activity count; P = .023), and the decrease was more evident in women with higher baseline physical function. Reduced daytime activity correlated with increased fatigue (ρ = -0.49; P = .017).

CONCLUSION

Daytime function decreased after initiation of AI therapy and correlated moderately with increased fatigue, although no association was identified with changes in pain or sleep quality. Additional studies are required to understand why function is reduced, which could have implications for interventions to improve patient tolerance of, and persistence with, AI therapy.

Dysregulation of Aromatase in Breast, Endometrial, and Ovarian Cancers: An Overview of Therapeutic Strategies

Aromatase is the rate-limiting enzyme in the biosynthesis of estrogens, which play crucial roles on a spectrum of developmental and physiological processes. The biological actions of estrogens are classically mediated by binding to two estrogen receptors (ERs), ERα and ERβ. Encoded by the cytochrome P450, family 19, subfamily A, polypeptide 1 (CYP19A1) gene, aromatase is expressed in a wide variety of tissues, as well as benign and malignant tumors, and is regulated in a pathway- and tissue-specific manner. Overexpression of aromatase, leading to elevated systemic levels of estrogen, is unequivocally linked to the pathogenesis and growth of a number malignancies, including breast, endometrium, and ovarian cancers. Aromatase inhibitors (AIs) are routinely used to treat estrogen-dependent breast cancers in postmenopausal women; however, their roles in endometrial and ovarian cancers remain obscure. While AI therapy is effective in hormone sensitive cancers, they diminish estrogen production throughout the body and, thus, generate undesirable side effects. Despite the effectiveness of AI therapy, resistance to endocrine therapy remains a major concern and is the leading cause of cancer death. Considerable advances, toward mitigating these issues, have evolved in conjunction with a number of histone deacetylase (HDAC) inhibitors for countering an assortment of diseases and cancers, including the aforesaid malignancies. HDACs are a family of enzymes that are frequently dysregulated in human tumors. This chapter will discuss the current understanding of aberrant regulation and expression of aromatase in breast, endometrial, and ovarian cancers, and potential therapeutic strategies for prevention and treatment of these life-threatening diseases.

Physician and Patient Barriers to Breast Cancer Preventive Therapy

The uptake of selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) for the primary prevention of breast cancer is low, despite their proven efficacy in several randomized clinical trials. This review summarizes the latest data on physicians' and women's barriers to breast cancer preventive therapy. Physicians' challenges include: identifying suitable candidates for preventive therapy, inadequate training and confidence in risk assessment and counselling, insufficient knowledge of risk-reducing medications, and lack of time. High-risk women fear medication side effects, and they often weigh experiences of others more heavily than statistical probabilities to guide their decision-making. Despite decision aid interventions to help women make an informed decision, acceptance of preventive therapy will remain low until: risk/benefit profiles are more favorable, physicians are better educated and skilled in having these discussions, and suitable biomarkers to monitor drug efficacy and better clinical risk prediction models to assess true individual risk are available.

Investigation of fluorinated and bifunctionalized 3-phenylchroman-4-one (isoflavanone) aromatase inhibitors

Fluorinated isoflavanones and bifunctionalized isoflavanones were synthesized through a one-step gold(I)-catalyzed annulation reaction. These compounds were evaluated for their in vitro inhibitory activities against aromatase in a fluorescence-based enzymatic assay. Selected compounds were tested for their anti-proliferative effects on human breast cancer cell line MCF-7. Compounds 6-methoxy-3-(pyridin-3-yl)chroman-4-one (3c) and 6-fluoro-3-(pyridin-3-yl)chroman-4-one (3e) were identified as the most potent aromatase inhibitors with IC₅₀ values of 2.5 μM and 0.8 μM. Therefore, these compounds have great potential for the development of pharmaceutical agents against breast cancer.