Survival with aromatase inhibitors and inactivators versus standard hormonal therapy in advanced breast cancer: meta-analysis

Therapeutic prospects of sex hormone receptor signaling in hormone-responsive cancers

Globally, hormone-responsive cancers afflict millions of people contributing to cancer-related morbidity and mortality. While hormone-responsive cancers overburden patients, their close families, and even health budgets at the local levels, knowledge of these cancers particularly their biology and possible avenues for therapy remains poorly exploited. Herewith, this review highlights the role of sex hormones (estrogens and androgens) in the pathophysiology of hormone-responsive cancers and the exploration of therapeutic targets. Major scientific databases including but not limited to Scopus, PubMed, Science Direct, Web of Science core collections, and Google Scholar were perused using a string of search terms: Hormone-responsive cancers, androgens and cancers, estrogens and cancer, androgen receptor signalling, estrogen receptor signalling, etc.

Strong Early Impact of Letrozole on Ovulation Induction Outperforms Clomiphene Citrate in Polycystic Ovary Syndrome

Polycystic ovary syndrome is a common endocrine disorder, characterized by hyperandrogenism and/or chronic oligo/anovulation, which leads to infertility. The aim of this systematic review and meta-analysis was to explore the efficacy of letrozole compared with clomiphene citrate for ovulation induction in women with polycystic ovarian syndrome. The study protocol has been registered with PROSPERO (registration number CRD42022376611). The literature search included randomized clinical trials. We conducted our systematic literature search across three medical databases: MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. The data synthesis employed a random effects model. Out of the 1994 articles screened, 25 studies fulfilled the inclusion criteria. The letrozole group exhibited a significant increase in endometrial thickness (mean difference = 1.70, confidence interval: 0.55-2.86; I2 = 97%, p-value = 0.008). The odds of ovulation (odds ratio = 1.8, confidence interval: 1.21-2.69; I2 = 51%, p-value = 0.010) and pregnancy (odds ratio = 1.96, confidence interval: 1.37-2.81; I2 = 32%, p-value = 0.002) were significantly higher. The resistance index of the subendometrial arteries showed a significant decrease (mean difference = -0.15, confidence interval: -0.27 to -0.04; I2 = 92%, p-value = 0.030). Women diagnosed with polycystic ovarian syndrome and treated with letrozole for ovulation induction had increased ovulation and pregnancy rates and increased endometrial thickness. The lower resistance index of subendometrial arteries can enhance intrauterine circulation, creating more favorable conditions for embryo implantation and development.

Aromatase Inhibitor Therapy Increases the Risk of New-Onset Atrial Fibrillation in Patients With Breast Cancer

Background

Previous studies suggest that aromatase inhibitors (AIs) increase the risk of adverse cardiovascular events and cardiac arrhythmias in patients with breast cancer, but it is unclear whether AIs also increase the risk of new-onset atrial fibrillation (AF).

Objectives

The purpose of this study was to investigate whether the use of AIs was associated with an increased risk of new-onset AF in patients with breast cancer.

Methods

We performed a retrospective analysis involving 5,707 patients with breast cancer (mean age 63.9 ± 11.2 years and 99.9% women) who received adjunctive hormone therapy with an AI (AI group, n = 4,878) or tamoxifen (tamoxifen group, n = 829) in Hong Kong between January 1, 1999, and December 31, 2020. After propensity score matching, there were 1,658 and 829 patients with balanced characteristics in the AI group and tamoxifen group, respectively.

Results

After 8,863 patient-years of follow-up, patients who were prescribed AI had a trend toward more new-onset arrhythmias compared with those prescribed tamoxifen (0.62 vs 0.30 per 100 patient-years; crude HR: 2.05; P = 0.053). The difference in arrhythmic risk was mainly driven by a higher incidence rate of new-onset AF in the AI group (0.59 vs 0.27 per 100 patient-years; crude HR: 2.18; P = 0.046). The use of AIs was confirmed to be an independent risk factor for new-onset AF on multivariate analysis (adjusted HR: 2.75; P = 0.01).

Conclusions

Among breast cancer patients prescribed adjunctive hormonal therapy, AI was associated with an increased risk of new-onset AF. Regular surveillance for new-onset AF should be considered in breast cancer patients treated with an AI.

Current Management and Future Perspectives of Hormone Receptor-Positive HER2-Negative Advanced Breast Cancer

OBJECTIVES

An overview of the best therapeutic approaches for the management of hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer is provided, and emerging treatment advances are discussed. Key nursing considerations and the role of the nurse in the provision of optimal care are explored.

DATA SOURCES

Data sources include peer-reviewed articles sourced in electronic databases.

CONCLUSION

With a multitude of current and emerging treatments for the management of hormone receptor-positive, HER2-negative advanced breast cancer, patients with this subtype have improved overall survival. It is essential that specialist nurses holistically support patients; this will ensure treatment adherence, leading to enhanced longevity and quality of life.

IMPLICATIONS FOR NURSING PRACTICE

Nurses play an important role in patient education and the early identification and management of treatment toxicities. Nurses also need to monitor and facilitate adherence by identifying barriers and implementing strategies to overcome them, ultimately improving patient outcomes.

Targeting the Tumor Microenvironment in Breast Cancer: Prognostic and Predictive Significance and Therapeutic Opportunities

Breast cancer is one of the most prevalent tumors among women. Its prognosis and treatment outcomes depend on factors related to tumor cell biology. However, recent studies have revealed the critical role of the tumor microenvironment (TME) in the development, progression, and treatment response of breast cancer. In this review, we explore the different components of the TME and their relevance as prognostic and predictive biomarkers in breast cancer. In addition, techniques for assessing the tumor microenvironment, such as immunohistochemistry or gene expression profiling, and their clinical utility in therapeutic decision-making are examined. Finally, therapeutic strategies targeting the TME are reviewed, highlighting their potential clinical benefits. Overall, this review emphasizes the importance of the TME in breast cancer and its potential as a clinical tool for better patient stratification and the design of personalized therapies.

The Clinical Benefits of Antiresorptive Agents in Patients with Primary Breast Cancer Receiving Adjuvant Endocrine Therapy: A Systematic Review with Pairwise and Network Meta-analysis

CONTEXT

Clinical trials have investigated the role of antiresorptive agents, including bisphosphonates and denosumab, in patients with primary breast cancer receiving adjuvant endocrine therapy, aiming for better bone protection and/or improving survival.

OBJECTIVE

To summarize the clinical effects of antiresorptive agents in patients with early breast cancer receiving endocrine therapy.

METHODS

We systematically reviewed and synthesized the clinical benefits and harms of antiresorptive agents in patients with early breast cancer receiving endocrine therapy by calculating the risk ratios (RRs).

RESULTS

In the pooled meta-analysis, antiresorptive agents had significant clinical benefits on disease recurrence (RR 0.78, 95% CI 0.67-0.90) and locoregional recurrence (RR 0.69, 95% CI 0.49-0.95) in patients with breast cancer receiving endocrine therapy. Early use of antiresorptive agents has a beneficial effect on secondary endocrine therapy resistance instead of primary resistance. Safety analysis revealed that potential risk for osteonecrosis of the jaw (ONJ, RR 3.29, 95% CI 1.12-9.68) with antiresorptive agents; however, there is an insignificant difference in arthralgia. The subgroup analyses revealed that intervention with bisphosphonates might have profound clinical benefits, but also increased the occurrence of ONJ. A network meta-analysis further supported the clinical effects of early antiresorptive agent use compared with delayed use or placebo.

CONCLUSION

Using antiresorptive agents early in patients with breast cancer receiving adjuvant endocrine therapy may provide additional benefits in risk reduction of recurrence, but there is a potential risk of ONJ.

Therapeutic resistance to anti-oestrogen therapy in breast cancer

The hormone receptor oestrogen receptor-α (ER) orchestrates physiological mammary gland development, breast carcinogenesis and the progression of breast tumours into lethal, treatment-refractory systemic disease. Selective antagonism of ER signalling has been one of the most successful therapeutic approaches in oncology, benefiting patients as both a cancer preventative measure and a cancer treatment strategy. However, resistance to anti-oestrogen therapy is a major clinical challenge. Over the past decade, we have gained an understanding of how breast cancers evolve under the pressure of anti-oestrogen therapy. This is best depicted by the case of oestrogen-independent mutations in the gene encoding ER (ESR1), which are virtually absent in primary breast cancer but highly prevalent (20-40%) in anti-oestrogen-treated metastatic disease. These and other findings highlight the 'evolvability' of ER+ breast cancer and the need to understand molecular processes by which this evolution occurs. Recent development and approval of next-generation ER antagonists to target ESR1-mutant breast cancer underscores the clinical importance of this evolvability and sets a new paradigm for the treatment of ER+ breast cancers.

A Systematic Review of Systematic Reviews on the Use of Aromatase Inhibitors for the Treatment of Endometriosis: The Evidence to Date

Endometriosis is a chronic gynecologic condition that affects around 6-10% of reproductive age women. This clinical entity is characterized with pelvic pain, dysmenorrhea, dyspareunia, and infertility which are the most often presenting symptoms. Aromatase P450 is the key enzyme for ovarian estrogen biosynthesis and there is evidence that endometriotic lesions express aromatase and are able to synthesize their own estrogens. Aromatase inhibitors (AIs) are potent drugs that suppress the estrogen synthesis via suppression of aromatase. We performed a systematic review of systematic reviews and narrative reviews on the use of aromatase inhibitors in the medical management of endometriosis. We searched: PubMed (1950-2022), Google Scholar (2004-2022), Cochrane Library (2010-2022) and Researchgate (2010-2022). The search included the following medical subject headings (MeSH) or keywords: "Aromatase Inhibitors" AND "Endometriosis" AND "Systematic reviews" OR "Systematic review" AND "Reviews" OR "Reviews" AND "Endometriosis". The electronic database search yielded initially 12,106 studies from the different databases. Further assessment of the studies resulted in exclusion of (n = 12,015) studies due to duplicates and irrelevance; Finally, 24 studies were selected for inclusion, 5 were Systematic reviews and 19 were Narrative reviews. The 5 systematic reviews were assessed by AMSTAR-2 criteria and were found to have low quality. Narrative reviews were assessed with SANRA criteria and were found to have high-quality aromatase inhibitors are potent drugs that can manage the endometriosis-related symptoms in cases where initial medical management has failed to show positive results. However, their use is limited by the adverse effects that are linked with menopausal symptoms. aromatase inhibitors can be administered as an alternative treatment in patients. Future studies with randomized design are required to reach safer conclusions and further investigation. These studies should define the therapeutic dose, new add-back therapy modalities. Future directions should examine the most-appropriate way of administration and the duration of therapy.

[Therapeutic strategies for the treatment of endocrine resistant hormone receptor positive advanced breast cancer]

HR+ breast cancers are defined by the prominence of signaling pathways dependent on the estrogen receptor. Endocrine therapy is the standard treatment for these advanced diseases. Resistance to these treatments, called hormone resistance, appears invariably with biological mechanisms that have led to the development of therapeutic opportunities. An exhaustive literature review was carried out concerning the biology of the hormone resistance pathways, the therapeutic options before the era of CDK4/6 inhibitors, the rise of CDK4/6 inhibitors and the therapeutic prospects in a situation of hormone resistance. Various biological abnormalities have been identified in the mechanisms of hormone resistance such as changes in the estrogen receptor, mutations in the ESR1 gene, aberrant activation of the PI3K pathway or cell cycle deregulations. Historical strategies for circumventing this hormone resistance have been based on hormonal manipulation, on the development of new endocrine therapy such as fulvestrant (selective estrogen receptor inhibitor, SERD), on combinations of treatments such as everolimus, a mTOR inhibitor. This strategy combining endocrine therapy and targeted therapy has led to the development of combinations with CDK4/6 inhibitors which have now become a standard treatment in the hormone resistance phase. The future of this therapeutic era remains to be written with new combinations of hormone therapy and targeted therapy such as PI3K inhibitors or even with the positioning of new SERDs in clinical development.

CHEOPS trial: a GINECO group randomized phase II assessing addition of a non-steroidal aromatase inhibitor to oral vinorelbine in pre-treated metastatic breast cancer patients

BACKGROUND

The objective of the CHEOPS trial was to assess the benefit of adding aromatase inhibitor (AI) to metronomic chemotherapy, oral vinorelbine, 50 mg, three times a week for pre-treated, HR + /HER2- metastatic breast cancer patients.

METHODS

In this multicentric phase II study, patients had to have progressed on AI and one or two lines of chemotherapy. They were randomized between oral vinorelbine (Arm A) and oral vinorelbine with non-steroidal AI (Arm B).

RESULTS

121 patients were included, 61 patients in Arm A and 60 patients in Arm B. The median age was 68 years. 109 patients had visceral metastases. They all had previously received an AI. The study had been prematurely stopped following the third death due to febrile neutropenia. Median PFS trend was found to be different with 2.3 months and 3.7 months in Arm A and Arm B, respectively (HR 0.73, 95%CI 0.50-1.06, p value = 0.0929). No statistical difference was shown in OS and better tumor response. 56 serious adverse events corresponding to 25 patients (21%) were reported (respectively, 12 (20%) versus 13 (22%) for arms A and B) (NS).

CONCLUSION

The addition of AI to oral vinorelbine over oral vinorelbine alone in aromatase inhibitor-resistant metastatic breast cancer was associated with a non-significant improvement of PFS. Several unexpected serious adverse events were reported. Metronomic oral vinorelbine schedule, at 50 mg three times a week, requires close biological monitoring. The question of hormonal treatment and chemotherapy combination remains open.

The Present and Future of Clinical Management in Metastatic Breast Cancer

Regardless of the advances in our ability to detect early and treat breast cancer, it is still one of the common types of malignancy worldwide, with the majority of patients decease upon metastatic disease. Nevertheless, due to these advances, we have extensively characterized the drivers and molecular profiling of breast cancer and further dividing it into subtypes. These subgroups are based on immunohistological markers (Estrogen Receptor-ER; Progesterone Receptor-PR and Human Epidermal Growth Factor Receptor 2-HER-2) and transcriptomic signatures with distinct therapeutic approaches and regiments. These therapeutic approaches include targeted therapy (HER-2+), endocrine therapy (HR+) or chemotherapy (TNBC) with optional combination radiotherapy, depending on clinical stage. Technological and scientific advances in the identification of molecular pathways that contribute to therapy-resistance and establishment of metastatic disease, have provided the rationale for revolutionary targeted approaches against Cyclin-Dependent Kinases 4/6 (CDK4/6), PI3 Kinase (PI3K), Poly ADP Ribose Polymerase (PARP) and Programmed Death-Ligand 1 (PD-L1), among others. In this review, we focus on the comprehensive overview of epidemiology and current standard of care treatment of metastatic breast cancer, along with ongoing clinical trials. Towards this goal, we utilized available literature from PubMed and ongoing clinical trial information from clinicaltrials.gov to reflect the up to date and future treatment options for metastatic breast cancer.

Safety and Efficacy of Ribociclib in Combination with Letrozole in Patients with HR+, HER2- Advanced Breast Cancer: Results from the Italian Subpopulation of Phase 3b CompLEEment-1 Study

BACKGROUND

Ribociclib plus letrozole demonstrated manageable safety and efficacy profiles in hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancer (ABC) in the Phase 3b CompLEEment-1 trial.

OBJECTIVE

To evaluate the safety and efficacy of ribociclib plus letrozole in the Italian subpopulation with HR+, HER2- ABC from the CompLEEment-1 trial.

PATIENTS AND METHODS

Patients with HR+, HER2- ABC received ribociclib (600 mg/day, 3 weeks on/1 week off) plus letrozole (2.5 mg/day) while men and premenopausal women additionally received goserelin. Patients were allowed with ≤ 1 line of prior chemotherapy and an Eastern Cooperative Oncology Group performance status of ≤ 2. The primary outcome included safety and tolerability.

RESULTS

Of the 554 Italian patients, 246 (44.4 %) patients completed treatment. The reasons for treatment discontinuation included progressive disease (PD; 36.6 %), adverse events (AEs; 11.9 %), and death (1.6 %). All-grade AEs and grade ≥ 3 AEs occurred in 98.9 % and 77.8 % patients, respectively. The most common treatment-related AEs were neutropenia (73.6 %), followed by leukopenia (32.1 %), and nausea (25.3 %). The overall response rate was 28.2 % (95 % confidence interval [CI], 24.4-32.1); clinical benefit rate was 71.7 % (95 % CI, 67.7-75.4); and median time to progression was 26.7 months (95 % CI, 24.8-non-estimable). Health-related quality of life scores were maintained during treatment.

CONCLUSION

The safety and efficacy profiles of ribociclib plus letrozole in the Italian subpopulation was found to be consistent with the CompLEEment-1 global population result, MONALEESA-2, and MONALEESA-7 outcomes, which reaffirm ribociclib plus letrozole as the frontline treatment option in patients with HR+, HER2- ABC.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

NCT02941926 (30 November 2016).

[Endocrine Treatments in Breast Cancer]

Endocrine Treatments in Breast Cancer Abstract. Breast cancer, the most common cancer in women, expresses estrogen and/or progesterone receptors in about 75% of patients. This allows for the use of endocrine treatments. Adjuvant therapy with tamoxifen for 5 years reduces the mortality by about 33%; the residual risk can be lowered by using aromatase inhibitors and by prolonging the treatment. In patients with advanced disease, the median duration of response to first-line therapy is about twelve months, and the median survival time is 20 to 40 months. The use of the various substances differs in terms of duration, sequence, and combinations, particularly with CDK4/6-inhibitors, depending on the clinical situation. Endocrine therapies are prescribed over a long period of time. Treatment adherence is improved by optimal control of side effects.

Dissecting the Roles of PDCD4 in Breast Cancer

The human programmed cell death 4 (PDCD4) gene was mapped at chromosome 10q24 and encodes the PDCD4 protein comprised of 469 amino acids. PDCD4 inhibits protein translation PDCD4 inhibits protein translation to suppress tumor progression, and its expression is frequently decreased in breast cancer. PDCD4 blocks translation initiation complex by binding eIF4A via MA-3 domains or by directly binding 5’ mRNA internal ribosome entry sites with an RNA binding domain to suppress breast cancer progression and proliferation. Numerous regulators and biological processes including non-coding RNAs, proteasomes, estrogen, natural compounds and inflammation control PDCD4 expression in breast cancer. Loss of PDCD4 expression is also responsible for drug resistance in breast cancer. HER2 activation downregulates PDCD4 expression by activating MAPK, AKT, and miR-21 in aromatase inhibitor-resistant breast cancer cells. Moreover, modulating the microRNA/PDCD4 axis maybe an effective strategy for overcoming chemoresistance in breast cancer. Down-regulation of PDCD4 is significantly associated with short overall survival of patients, which suggests that PDCD4 may be an independent prognostic marker for breast cancer.

Next-generation selective estrogen receptor degraders and other novel endocrine therapies for management of metastatic hormone receptor-positive breast cancer: current and emerging role

Endocrine therapy (ET) is a pivotal strategy to manage early- and advanced-stage estrogen receptor-positive (ER+) breast cancer. In patients with metastatic breast cancer (MBC), progression of disease inevitably occurs due to the presence of acquired or intrinsic resistance mechanisms. ET resistance can be driven by ligand-independent, ER-mediated signaling that promotes tumor proliferation in the absence of hormone, or ER-independent oncogenic signaling that circumvents endocrine regulated transcription pathways. Estrogen receptor 1 (ESR1) mutations induce constitutive ER activity and upregulate ER-dependent gene transcription, provoking resistance to estrogen deprivation and aromatase inhibitor therapy. The role ESR1 mutations play in regulating response to other therapies, such as the selective estrogen receptor degrader (SERD) fulvestrant and the available CDK4/6 inhibitors, is less clear. Novel oral SERDs and other next-generation ETs are in clinical development for ER+ breast cancer as single agents and in combination with established targeted therapies. Recent results from the phase III EMERALD trial demonstrated improved outcomes with the oral SERD elacestrant compared to standard anti-estrogen therapies in ER+ MBC after prior progression on ET, and other agents have shown promise in both the laboratory and early-phase clinical trials. In this review, we will discuss the emerging data related to oral SERDs and other novel ET in managing ER+ breast cancer. As clinical data continue to mature on these next-generation ETs, important questions will emerge related to the optimal sequence of therapeutic options and the genomic and molecular landscape of resistance to these agents.

Mitochondrial stress adaptation promotes resistance to aromatase inhibitor in human breast cancer cells via ROS/calcium up-regulated amphiregulin-estrogen receptor loop signaling

Many breast cancer patients harbor high estrogen receptor (ER) expression in tumors that can be treated with endocrine therapy, which includes aromatase inhibitors (AI); unfortunately, resistance often occurs. Mitochondrial dysfunction has been thought to contribute to progression and to be related to hormone receptor expression in breast tumors. Mitochondrial alterations in AI-resistant breast cancer have not yet been defined. In this study, we characterized mitochondrial alterations and their roles in AI resistance. MCF-7aro AI-resistant breast cancer cells were shown to have significant changes in mitochondria. Low expressions of mitochondrial genes and proteins could be poor prognostic factors for breast cancer patients. Long-term mitochondrial inhibitor treatments-mediated mitochondrial stress adaptation could induce letrozole resistance. ERα-amphiregulin (AREG) loop signaling was activated and contributed to mitochondrial stress adaptation-mediated letrozole resistance. The up-regulation of AREG-epidermal growth factor receptor (EGFR) crosstalk activated the PI3K/Akt/mTOR and ERK pathways and was responsible for ERα activation. Moreover, mitochondrial stress adaptation-increased intracellular levels of reactive oxygen species (ROS) and calcium were shown to induce AREG expression and secretion. In conclusion, our results support the claim that mitochondrial stress adaptation contributes to AI resistance via ROS/calcium-mediated AREG-ERα loop signaling and provide possible treatment targets for overcoming AI resistance.

Management of hormone receptor-positive, human epidermal growth factor 2-negative metastatic breast cancer

Estrogen receptor (ER) is the major driver of most metastatic breast cancers (mBCs). Endocrine therapy (ET) is the most effective treatment for ER + mBC, but its effectiveness is limited by high rates of de novo and acquired resistance. A growing understanding of the biological characteristics and complexity of the ER pathway and the mechanisms of ET resistance has led to the development of a new generation of targeted therapies. One such mechanism is the cell cycle signaling pathways, which lead to the development of cyclin-dependent kinase 4/6 inhibitors (CDK4/6is) that have, in turn, transformed the management of such tumors. Another important mechanism is the alteration of the phosphatidylinositol 3'-kinase/AKT/mammalian target of rapamycin pathway. Drugs targeting each component of these pathways are currently used in clinical practice, and several more are in development. As a result, a myriad of new targeted therapies are consistently being added to the clinical oncologist armamentarium. Navigating the evolving and highly complex treatment landscape of HR + /HER2- mBC remains both an art and a challenge. In this review, we discuss the biological features of HR + /HER2- mBC and the different mechanisms of resistance to ET. We also discuss the management of mBC as the disease changes from endocrine-sensitive to endocrine-resistant.

From clinical trials to clinical practice: the use of everolimus and exemestane in the treatment of hormone receptor-positive metastatic breast cancer: real-world data

Everolimus combined with exemestane can modulate endocrine resistance. The combination showed significant improvement in progression-free survival (PFS) in phase III clinical trials for hormone receptor positive metastatic breast cancer patients. It also showed serious adverse events. We evaluate the efficacy and prevalence of serious adverse events in a real-world setting. We retrospectively examined 91 breast cancer patients; all were previously treated with chemotherapy and fulvestrant (84% and 59%, respectively). After a 13-month median follow-up, 29% had a partial response, and 32% had stable disease. The PFS was 7.8 months. Due to adverse events, 19% of patients stopped the treatment, while 31% required a dose reduction. Despite enrolling heavier-pretreated patients, our real-world outcome for the efficacy and safety of the exemestane and everolimus match those of the clinical trials. Such results should assure clinicians and lead to wider adoption of this oral, chemotherapy-sparing regimen.

Estrogen as an Essential Resource and the Coexistence of ER+ and ER– Cancer Cells

Diagnosis of estrogen sensitivity in breast cancer is largely predicated on the ratio of ER+ and ER– cancer cells obtained from biopsies. Estrogen is a growth factor necessary for cell survival and division. It can also be thought of as an essential resource that can act in association with other nutrients, glucose, glutamine, fatty acids, amino acids, etc. All of these nutrients, collectively or individually, may limit the growth of the cancer cells (Liebig’s Law of the Minimum). Here we model estrogen susceptibility in breast cancer as a consumer-resource interaction: ER+ cells require both estrogen and glucose as essential resources, whereas ER– only require the general resource. The model predicts that when estrogen is the limiting factor, other nutrients may go unconsumed and available at higher levels, thus permitting the invasion of ER– cells. Conversely, when ER– cells are less efficient on glucose than ER+ cells, then ER– cells limited by glucose may be susceptible to invasion by ER+ cells, provided that sufficient levels of estrogen are available. ER+ cells will outcompete ER– cells when estrogen is abundant, resulting in low concentrations of interstitial glucose within the tumor. In the absence of estrogen, ER– cells will outcompete ER+ cells, leaving a higher concentration of interstitial glucose. At intermediate delivery rates of estrogen and glucose, ER+ and ER– cells are predicted to coexist. In modeling the dynamics of cells in the same tumor with different resource requirements, we can apply concepts and terms familiar to many ecologists. These include: resource supply points, R∗, ZNGI (zero net growth isoclines), resource depletion, and resource uptake rates. Based on the circumstances favoring ER+ vs. ER– breast cancer, we use the model to explore the consequences of therapeutic regimens that may include hormonal therapies, possible roles of diet in changing cancer cell composition, and potential for evolutionarily informed therapies. More generally, the model invites the viewpoint that cancer’s eco-evolutionary dynamics are a consumer-resource interaction, and that other growth factors such as EGFR or androgens may be best viewed as essential resources within these dynamics.

LG-ESSs and HG-ESSs: underlying molecular alterations and potential therapeutic strategies

Endometrial stromal tumors (ESTs) include endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS), and undifferentiated uterine sarcoma (UUS). Since these are rare tumor types, there is an unmet clinical need for the systematic therapy of advanced LG-ESS or HG-ESS. Cytogenetic and molecular advances in ESTs have shown that multiple recurrent gene fusions are present in a large proportion of LG-ESSs, and HG-ESSs are identified by the tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein epsilon (YWHAE)-family with sequence similarity 22 (FAM22) fusion. Recently, a group of ESSs harboring both zinc finger CCCH domain-containing protein 7B (ZC3H7B)-B-cell lymphoma 6 corepressor(BCOR) fusion and internal tandem duplication (ITD) of the BCOR gene have been provisionally classified as HG-ESSs. In this review, we firstly describe current knowledge about the molecular characteristics of recurrent aberrant proteins and their roles in the tumorigenesis of LG-ESSs and HG-ESSs. Next, we summarize the possibly shared signal pathways in the tumorigenesis of LG-ESSs and HG-ESSs, and list potentially actionable targets. Finally, based on the above discussion, we propose a few promising therapeutic strategies for LG-ESSs and HG-ESSs with recurrent gene alterations.

Optimizing treatment selection, and sequencing decisions for Management of HR-Positive, HER2-Negative advanced breast cancer - Proceedings from breast cancer expert group meeting

PURPOSE

The therapeutic landscape of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC) has evolved considerably with the introduction of newer targeted agents and their combinations with endocrine therapies. In this scenario, optimizing treatment selection and sequencing is daunting for clinicians. The purpose of this review is to provide evidence-based answers to key clinical questions on treatment selection and sequencing for the management of HR + HER2 - mBC.

DESIGN

A panel of nine key opinion leaders from Argentina, Brazil, Colombia, Mexico, Moscow, Singapore, South Korea, Taiwan, and UAE convened in October 2018. They reviewed the literature and formulated answers to clinical questions on optimizing the management of HR + HER2 - mBC.

RESULTS

Evidence-based answers were formulated for: (1) optimal initial treatment choice; (2) ovarian function suppression, optimal endocrine partner, and role of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors (in premenopausal women); (3) better first-line standard of care than aromatase inhibitors; (4) preferred second-line treatment; (5) treatment of oligometastatic disease; (6) factors influencing first-line single-agent endocrine therapy choice; (7) influence of endocrine resistance on treatment selection; (8) optimal maintenance regimen in visceral crisis; and (9) need for a breast cancer registry for patients with HR + HER2 - mBC. The panel also proposed a treatment-sequencing algorithm for the management of HR + HER2 - mBC.

CONCLUSION

The current article will serve as a comprehensive guide for optimizing the management of HR + HER2 - mBC. The proposed breast cancer registry will help identify unmet needs and develop strategic regional policies to help improve access to optimized care for HR + HER2 - mBC.

Advances in endocrine and targeted therapy for hormone-receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer

Nearly 70% of breast cancer (BC) is hormone-receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, and endocrine therapy is the mainstay of treatment for this subtype. However, intrinsic or acquired endocrine resistance can occur during the endocrine treatment. Based on insights of endocrine resistance mechanisms, a number of targeted therapies have been and continue to be developed. With regard to HR-positive, HER2-negative advanced BC, aromatase inhibitor (AI) is superior to tamoxifen, and fulvestrant is a better option for patients previously exposed to endocrine therapy. Targeted drugs, such as cyclin-dependent kinases (CDK) 4/6 inhibitors, mammalian target of rapamycin (mTOR) inhibitors, phosphoinositide-3-kinase (PI3K) inhibitors, and histone deacetylase (HDAC) inhibitors, play a significant role in the present and show a promising future. With the application of CDK4/6 inhibitors becoming common, mechanisms of acquired resistance to them should also be taken into consideration.

Current Landscape of Targeted Therapy in Hormone Receptor-Positive and HER2-Negative Breast Cancer

Background: Hormone receptor-positive and HER2-negative breast cancer (HR + BC) is the most prevalent breast cancer. Endocrine therapy is the mainstay of treatment, however, due to the heterogeneous nature of the disease, resistance to endocrine therapy is not uncommon. Over the past decades, the emergence of novel targeted therapy in combination with endocrine therapy has shown improvement in outcomes of HR + BC. This paper reviews available data of targeted therapy and the results of pivotal clinical trials in the management of HR + BC. Methods: A literature search in PubMed and Google Scholar was performed using keywords related to HR + BC and targeted therapy. Major relevant studies that were presented in international cancer research conferences were also included. Results: Endocrine therapy with tamoxifen and aromatase inhibitors are backbone treatments for women with early-stage HR + BC leading to a significant reduction in mortality. They can also be used for primary prevention in women with a high risk of breast cancer. Preliminary data has shown the efficacy of adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitor, abemaciclib, in high-risk disease in combination with aromatase inhibitors. For most women with advanced HR + BC, endocrine therapy is the primary treatment. Recent evidence has shown that the use of CKD 4/6 inhibitors, mTOR inhibitors, and PI3K inhibitors in combination with endocrine therapy has been associated with better outcomes and delays initiation of chemotherapy. Several novel agents are under study for HR + BC. Discussion: Targeted treatment options for HR + BC have evolved. The future of overcoming resistance to targeted therapy, novel compounds, and predictive markers are key to improving HR + BC outcomes.

Advances in Therapy for Hormone Receptor (HR)-Positive, Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Advanced Breast Cancer Patients Who Have Experienced Progression After Treatment with CDK4/6 Inhibitors

Approximately 70% of breast cancer (BC) cases are hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) BC. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have acted as star drugs for reversing endocrine therapy (ET) resistance and improving the prognosis of patients with HR+ advanced breast cancer (ABC) since they were initially approved. However, progression eventually occurs. In this review, we summarize the recent treatment strategies post CDK4/6 inhibitors: 1) CDK4/6 inhibitors plus exemestane and everolimus; 2) phosphoinositide-3-kinase (PI3K) inhibitor alpelisib plus fulvestrant for patients with PIK3CA mutation; 3) poly (ADP-ribose) polymerase (PARP) inhibitor for patients with germline PALB2 mutations, somatic BRCA1/2 mutations, or germline BRCA1/2 mutations; 4) exemestane and everolimus; and (5) chemotherapy. These strategies are all supported by evidence from clinical trials and retrospective studies. We also describe potential future treatment strategies post CDK4/6 inhibitors, such as the trophoblast cell surface antigen 2 (Trop-2) directed antibody–drug conjugate, cyclin-dependent kinase 7 (CDK7) inhibitors, and B-cell lymphoma-2 (BCL-2) inhibitors.

Safety and efficacy of everolimus (EVE) plus exemestane (EXE) in postmenopausal women with locally advanced or metastatic breast cancer: final results from EVEREXES

BACKGROUND

This study was conducted to collect clinical safety, tolerability, and efficacy data with the use of everolimus (EVE) combined with exemestane (EXE) in patients with advanced breast cancer (ABC).

METHODS

The EVEREXES trial initiated in 2012, provided early access to the first dual blockade treatment with EVE + EXE in patients with HR+, HER2 - ABC in Asia and other emerging growth countries. Postmenopausal women with HR+, HER2 - ABC who had documented recurrence or progression, following a nonsteroidal aromatase inhibitor therapy, were treated with EVE (10 mg/day) + EXE (25 mg/day) orally.

RESULTS

A total of 235 patients received ≥ 1 dose of study medication. At the end of the study, all patients ceased the treatment. Disease progression (66.0%) was the primary reason of discontinuation. The most common AEs (≥ 20%) were stomatitis, decreased appetite, hyperglycemia, rash, aspartate aminotransferase increased, anemia, alanine aminotransferase increased, cough, and fatigue. No new safety concerns were identified in the current study. Median progression-free survival (PFS) in the Asian subset was similar to that of the overall population (9.3 months in both groups). Confirmed overall response rate (ORR) was achieved for 19.6% of the patients. Efficacy of EVE + EXE across subgroups (prior CT, line of treatment, and presence of visceral metastases) was maintained.

CONCLUSION

The safety and efficacy results from EVEREXES trial are consistent to data previously reported in BOLERO-2. These results support that EVE + EXE could be a viable treatment option for the postmenopausal women with HR+, HER2 - ABC in Asian region.

Therapeutic Advances in Oncology

Around 77 new oncology drugs were approved by the FDA in the past five years; however, most cancers remain untreated. Small molecules and antibodies are dominant therapeutic modalities in oncology. Antibody-drug conjugates, bispecific antibodies, peptides, cell, and gene-therapies are emerging to address the unmet patient need. Advancement in the discovery and development platforms, identification of novel targets, and emergence of new technologies have greatly expanded the treatment options for patients. Here, we provide an overview of various therapeutic modalities and the current treatment options in oncology, and an in-depth discussion of the therapeutics in the preclinical stage for the treatment of breast cancer, lung cancer, and multiple myeloma.

Simultaneous analysis of E1 and E2 by LC-MS/MS in healthy volunteers: estimation of reference intervals and comparison with a conventional E2 immunoassay

Monitoring estrogen levels, especially estradiol (E2), is amongst others important for determining menopausal status and guidance of breast cancer treatment. We validated a serum E2 and estrone (E1) liquid chromatography tandem-mass spectrometry assay (LC-MS/MS) suitable for quantitation in human subjects. In addition, we compared our method with an E2 immunoassay (IA) and established preliminary reference values. Validation parameters were within the predetermined acceptance criteria. Assay linearity ranges were 4-1500 pmol/L for E1 and 4-2500 pmol/L for E2. Imprecision ranged from 7.4 to 9.6%. The lower limit of quantitation for E2 (8.0 pmol/L) was 11.4 times lower than the IA. The method comparison revealed differences in E2 quantitation up to 155% between both methods. The method allowed quantitation of E1 in all healthy volunteers, while E2 could not be detected in 95% versus 40% of the post-menopausal women using IA and LC-MS/MS, respectively. Male, pre-, peri- and postmenopausal female reference values were estimated. An LC-MS/MS based method combining E1 and E2 analysis was validated with superior E2 analytical sensitivity when compared to the IA.

SAR439859, a Novel Selective Estrogen Receptor Degrader (SERD), Demonstrates Effective and Broad Antitumor Activity in Wild-Type and Mutant ER-Positive Breast Cancer Models

Primary treatment for estrogen receptor-positive (ER+) breast cancer is endocrine therapy. However, substantial evidence indicates a continued role for ER signaling in tumor progression. Selective estrogen receptor degraders (SERD), such as fulvestrant, induce effective ER signaling inhibition, although clinical studies with fulvestrant report insufficient blockade of ER signaling, possibly due to suboptimal pharmaceutical properties. Furthermore, activating mutations in the ER have emerged as a resistance mechanism to current endocrine therapies. New oral SERDs with improved drug properties are under clinical investigation, but the biological profile that could translate to improved therapeutic benefit remains unclear. Here, we describe the discovery of SAR439859, a novel, orally bioavailable SERD with potent antagonist and degradation activities against both wild-type and mutant Y537S ER. Driven by its fluoropropyl pyrrolidinyl side chain, SAR439859 has demonstrated broader and superior ER antagonist and degrader activities across a large panel of ER+ cells, compared with other SERDs characterized by a cinnamic acid side chain, including improved inhibition of ER signaling and tumor cell growth. Similarly, in vivo treatment with SAR439859 demonstrated significant tumor regression in ER+ breast cancer models, including MCF7-ESR1 wild-type and mutant-Y537S mouse tumors, and HCI013, a patient-derived tamoxifen-resistant xenograft tumor. These findings indicate that SAR439859 may provide therapeutic benefit to patients with ER+ breast cancer, including those who have resistance to endocrine therapy with both wild-type and mutant ER.

Osteoporotic Fractures of the Spine, Hip, and Other Locations after Adjuvant Endocrine Therapy with Aromatase Inhibitors in Breast Cancer Patients: a Meta-analysis

BACKGROUND

Aromatase inhibitors (AIs) play an important role in the endocrine therapy of postmenopausal breast cancer patients, with a recent tendency to extend the duration of their use. However, AIs may increase the risk of osteoporotic bone fractures. This meta-analysis evaluated the risk of osteoporotic fractures of the hip, spine, and other locations in breast cancer patients using AIs.

METHODS

We performed a systematic search to identify randomized controlled clinical trials that investigated osteoporotic fractures in breast cancer patients on AI therapy. The main outcomes were the incidence and risk of osteoporotic fractures in general and of hip, vertebral, and non-vertebral fractures in AI users and controls.

RESULTS

The systematic review found a total of 30 randomized controlled trials including 117,974 participants. The meta-analysis showed a higher incidence of osteoporotic fracture in AI users: The crude risk ratio for all osteoporotic fractures was 1.35 (95% confidence interval [CI], 1.29-1.42; P < 0.001), for hip fractures 1.18 (95% CI, 1.02-1.35; P < 0.001), for vertebral fractures 1.84 (95% CI, 1.36-2.49; P < 0.001), and for non-vertebral fractures 1.18 (95% CI, 1.02-1.35; P < 0.001), respectively, compared to the controls.

CONCLUSION

Our meta-analysis suggested an increased risk of osteoporotic fractures for AI therapy in patients with breast cancer that was most expressed for vertebral fractures. Breast cancer patients on AIs need to be monitored for osteoporosis and osteoporotic fractures, and active prevention measures should be implemented.

Pharmacogenomics of aromatase inhibitors in postmenopausal breast cancer and additional mechanisms of anastrozole action

Aromatase inhibitors (AIs) reduce breast cancer recurrence and prolong survival, but up to 30% of patients exhibit recurrence. Using a genome-wide association study of patients entered on MA.27, a phase III randomized trial of anastrozole versus exemestane, we identified a single nucleotide polymorphism (SNP) in CUB And Sushi multiple domains 1 (CSMD1) associated with breast cancer–free interval, with the variant allele associated with fewer distant recurrences. Mechanistically, CSMD1 regulates CYP19 expression in an SNP- and drug-dependent fashion, and this regulation is different among 3 AIs: anastrozole, exemestane, and letrozole. Overexpression of CSMD1 sensitized AI-resistant cells to anastrozole but not to the other 2 AIs. The SNP in CSMD1 that was associated with increased CSMD1 and CYP19 expression levels increased anastrozole sensitivity, but not letrozole or exemestane sensitivity. Anastrozole degrades estrogen receptor α (ERα), especially in the presence of estradiol (E2). ER⁺ breast cancer organoids and AI- or fulvestrant-resistant breast cancer cells were more sensitive to anastrozole plus E2 than to AI alone. Our findings suggest that the CSMD1 SNP might help to predict AI response, and anastrozole plus E2 serves as a potential new therapeutic strategy for patients with AI- or fulvestrant-resistant breast cancers.

A germline variation within the CSMD1 gene predicts aromatase inhibitor response in breast cancer.

Therapy options after CDK4/6 inhibitors for HR+, HER2- postmenopausal metastatic/recurrent breast cancer in Japan: a role for mammalian target of rapamycin inhibitors?

Despite advances in the treatment of hormone receptor-positive, HER2- metastatic breast cancer, the disease is rarely curable. In this review, we focus on the use of CDK4/6 inhibitors, examining clinical experience and the mechanisms underlying the development of resistance, and evaluating treatment options after failure to respond to CDK4/6 inhibitors. Current basic research supports the use of mammalian target of rapamycin inhibitors after CDK4/6 inhibitor failure; however, more data are needed, particularly regarding treatment sequencing. Real-world data studies may help to fill the current knowledge gap, particularly where large-scale randomized controlled studies are not feasible.

Structural Recognition and Binding Pattern Analysis of Human Topoisomerase II Alpha with Steroidal Drugs: In Silico Study to Switchover the Cancer Treatment

BACKGROUND AND OBJECTIVE

Topoisomerase TOP-IIA (TTOP-IIA) is widely used as a significant target for cancer therapeutics because of its involvement in cell proliferation. Steroidal drugs have been suggested for breast cancer treatment as aromatase enzymes inhibitors . TTOP-IIA inhibitors can be used as a target for the development of new cancer therapeutics.

MATERIALS AND METHODS

In this study, we conducted a docking study on steroidal drugs Anastrozole (ANA), Letrozole (LET), and exemestane (EXE) with TTOP-IIA  to explore the therapeutic area of these drugs.

RESULTS

The binding interaction of EXE drug had significant docking interaction which is followed by ANA and LET. Thus, all these drugs could be used to inhibit the TTOP-IIA mediated cell proliferation and could be a hope to treat the other types of cancers. Among all three tested steroidal drugs, EXE showed binding energy -7.05 kcal/mol, hydrogen bond length1.78289 Å and amino acid involved in an interaction was A: LYS723:HZ3 -: UNK1:O6.

CONCLUSION

The obtained data showed the most significant binding interaction analyzed with the tested enzyme. Thus, in vitro laboratory experimentation and in vivo research are necessary to put forward therapeutic repositioning of these drugs to establish them as a broad spectrum potential anticancer drugs.
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The Japanese Breast Cancer Society Clinical Practice Guidelines for systemic treatment of breast cancer, 2018 edition

Purpose

We present the English version of The Japanese Breast Cancer Society (JBCS) Clinical Practice Guidelines for systemic treatment of breast cancer, 2018 edition.

Methods

The JBCS formed a task force to update the JBCS Clinical Practice Guidelines, 2015 edition, according to Minds Handbook for Clinical Practice Guideline Development 2014. First, we set multiple outcomes for each clinical question (CQ). Next, quantitative or qualitative systematic review was conducted for each of the multiple outcomes, and the strength of recommendation for the CQ was taken into consideration during meetings, with the aim of finding a balance between benefit and harm. Finalized recommendations from each session were confirmed through discussion and voting at the recommendation decision meeting.

Results

The recommendations, the strength of recommendation and the strength of evidence were determined based on systemic literature reviews and the meta-analyses for each CQ.

Conclusion

The JBCS updated the Clinical Practice Guidelines for systemic treatment of breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s12282-020-01085-0) contains supplementary material, which is available to authorized users.

Breast Cancer, Version 3.2020, NCCN Clinical Practice Guidelines in Oncology

Several new systemic therapy options have become available for patients with metastatic breast cancer, which have led to improvements in survival. In addition to patient and clinical factors, the treatment selection primarily depends on the tumor biology (hormone-receptor status and HER2-status). The NCCN Guidelines specific to the workup and treatment of patients with recurrent/stage IV breast cancer are discussed in this article.

Risk of Osteoporotic Fracture in Patients with Breast Cancer: Meta-Analysis

Background

The fracture risk induced by anti-estrogen therapy in patients with breast cancer remains controversial. The aim of this study was to perform a meta-analysis and systematic review to evaluate the risk of osteoporotic fracture in patients with breast cancer.

Methods

A systematic search was performed to identify studies that included any osteoporotic fracture (hip fracture and vertebral fracture) in patients breast cancer. Main outcome measures were occurrence and risk of osteoporotic fractures including hip and vertebral fractures in patients and controls.

Results

A systematic search yielded a total of 4 studies that included osteoporotic fracture outcomes in patients with breast cancer. Meta-analysis showed a higher risk of osteoporotic fracture in patients with breast cancer. Analysis of these 4 studies involving a total of 127,722 (23,821 cases and 103,901 controls) patients showed that the incidence of osteoporotic fractures was higher in the breast cancer group than in the control group. The pooled estimate of crude relative risk for osteoporotic fracture was 1.35 (95% confidence interval, 1.29-1.42; P<0.001).

Conclusions

Although studies were limited by a small number, results suggested a possible association between anti-estrogen therapy and increased risk of osteoporotic fractures in patients with breast cancer.

Cannabinoids and Hormone Receptor-Positive Breast Cancer Treatment

Breast cancer (BC) is the most common cancer in women worldwide. Approximately 70–80% of BCs express estrogen receptors (ER), which predict the response to endocrine therapy (ET), and are therefore hormone receptor-positive (HR+). Endogenous cannabinoids together with cannabinoid receptor 1 and 2 (CB1, CB2) constitute the basis of the endocannabinoid system. Interactions of cannabinoids with hypothalamic–pituitary–gonadal axis hormones are well documented, and two studies found a positive correlation between peak plasma endogenous cannabinoid anandamide with peak plasma 17β-estradiol, luteinizing hormone and follicle-stimulating hormone levels at ovulation in healthy premenopausal women. Do cannabinoids have an effect on HR+ BC? In this paper we review known and possible interactions between cannabinoids and specific HR+ BC treatments. In preclinical studies, CB1 and CB2 agonists (i.e., anandamide, THC) have been shown to inhibit the proliferation of ER positive BC cell lines. There is less evidence for antitumor cannabinoid action in HR+ BC in animal models and there are no clinical trials exploring the effects of cannabinoids on HR+ BC treatment outcomes. Two studies have shown that tamoxifen and several other selective estrogen receptor modulators (SERM) can act as inverse agonists on CB1 and CB2, an interaction with possible clinical consequences. In addition, cannabinoid action could interact with other commonly used endocrine and targeted therapies used in the treatment of HR+ BC.

High-Dose Toremifene as a Promising Candidate Therapy for Hormone Receptor-Positive Metastatic Breast Cancer with Secondary Resistance to Aromatase Inhibitors

There are currently no established second- and later-line therapies for postmenopausal women with hormone receptor-positive advanced or metastatic breast cancer. We examined the efficacy of high-dose toremifene (HD-TOR) for this patient group and whether aromatase inhibitor (AI) resistance influences HD-TOR treatment outcome. This retrospective analysis investigated the outcomes of 19 women with postmenopausal hormone-sensitive recurrent or metastatic breast cancer who received HD-TOR, defined as 120 mg daily from 2012 to 2016. The median follow-up duration was 9.67 months. The overall response rate (ORR) and clinical benefit rate (CBR) were compared between various clinical subgroups, including patients exhibiting primary or secondary AI resistance as defined by the timing of recurrence or progression. Time to treatment failure (TTF) was estimated by the Kaplan–Meier method and compared between subgroups by the log-rank test. The overall ORR was 21.1%, and the CBR was 31.6%. CBR was significantly higher for patients without liver metastasis (50% vs. 0%, p = 0.044). Nine cases exhibited primary and eight cases secondary AI resistance. Both ORR and CBR were higher in patients with secondary AI resistance (25% vs. 0%, p = 0.087; 38% vs. 11%, p = 0.29). The median TTF was 6.2 months in the entire AI-resistant group (n = 17) and was longer in the secondary resistance subgroup than in the primary resistance subgroup (8.40 vs. 4.87 months; log-rank: p = 0.159). High-dose TOR appears to be most effective for postmenopausal breast cancer cases with secondary resistance to AIs, cases without prior AI treatment, and cases without liver metastasis. The detailed mechanisms of AI resistance and the clinical features of responsive cases need to be further clarified to identify the best candidates for HD-TOR.

First-line endocrine therapy for postmenopausal patients with hormone receptor-positive, HER2-negative metastatic breast cancer: a systematic review and meta-analysis

Background

In establishing the 2018 Breast Cancer Practice Guidelines of the Japan Breast Cancer Society, we explored the optimal first-line endocrine therapy for advanced postmenopausal hormone receptor-positive breast cancer.

Methods

We performed a systematic review of relevant reports from randomized-controlled studies published prior to November 2016 found using medical journal search engines. The main outcomes which we evaluated were progression-free survival (PFS), objective response rate (ORR), disease control rate (CBR), and toxicity.

Results

Four controlled trials comparing aromatase inhibitors (AI) and cyclin-dependent kinase (CDK)4/6 inhibitor combination therapy to AI monotherapy, and two controlled trials comparing anastrozole to fulvestrant 500 mg were analyzed. AI/CDK4/6 inhibitor combination therapy significantly improved PFS (Risk Ratio: 0.67, 95%CI 0.60–0.73), increased ORR (Risk Difference: 0.11, 95% CI 0.07–0.16), and increased CBR (Risk Difference: 0.11, 95% CI 0.07–0.15), compared with AI monotherapy. Patients who received this combination therapy had a higher grade ≥ 3 adverse event rate more than those who received AI monotherapy (Risk Difference: 43%, 95%CI: 0.39–0.47). Fulvestrant 500 mg alone significantly improved PFS (risk ratio: 0.85, 95%CI 0.72–0.98), but ORR and CBR were similar to those of anastrozole alone.

Conclusion

In the first-line treatment for advanced postmenopausal hormone receptor-positive breast cancer, a combination therapy of CDK4/6 inhibitors and AI showed significant improvement of PFS, ORR, and CBR but with significant increased toxicities compared with AI alone. Fulvestrant 500 mg monotherapy significantly prolonged PFS compared with AI monotherapy. We must wait for the results of the studies with longer follow-up period.

Capecitabine-Based Chemoendocrine Combination as First-Line Treatment for Metastatic Hormone-Positive Metastatic Breast Cancer: Phase 2 Study

BACKGROUND

Preclinical studies have suggested a synergistic effect of tamoxifen and capecitabine in estrogen receptor-positive cell lines. We evaluated the safety and efficacy of first-line chemoendocrine treatment in patients with metastatic breast cancer. Biochemical assessment was performed of serum levels of thymidine phosphorylase enzyme (TP), serum tamoxifen, hydroxytamoxifen, and 5-fluorouracil in relationship to efficacy.

PATIENTS AND METHODS

This prospective phase 2 interventional study studied patients with estrogen receptor-positive, HER2^- metastatic breast cancer who received either tamoxifen/capecitabine or letrozole/capecitabine as first-line treatment. The dose of capecitabine provided at 2000 mg per day continuously as a fixed dose.

RESULTS

Forty women with a median age of 49.3 years were enrolled. For the whole study group, median progression-free survival (PFS) was 10 months and median overall survival (OS) was 23.3 months. The overall response rate was 60% and the clinical benefit rate 82.5%. Progesterone receptor positivity was associated with significantly longer PFS (12 vs. 7 months, P = .021). The most frequent adverse events were palmar-plantar erythrodysesthesia (62.5%), fatigue (62.5%), diarrhea (30%), abdominal pain (12.5%), and constipation (10%). Changes in serum level of TP were not correlated to response to treatment, PFS, or OS. Higher serum levels of tamoxifen and hydroxytamoxifen were correlated with higher response rates and longer PFS but not OS.

CONCLUSION

Chemoendocrine treatment is well tolerated, with no evidence of contradictory effects between the combination components. However, the efficacy data need more validation.

Efficacy and Safety of Palbociclib and Fulvestrant in Japanese Patients With ER+/HER2- Advanced/Metastatic Breast Cancer

BACKGROUND/AIM

Published data have shown that palbociclib-fulvestrant can significantly improve the progression-free survival (PFS) of estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) metastatic breast cancer patients, but not of Japanese patients. We conducted this retrospective study to verify the efficacy and safety of palbociclib-fulvestrant in Japanese patients.

PATIENTS AND METHODS

ER+/HER2- metastatic breast cancer patients treated with fulvestrant (n=39) or palbociclib-fulvestrant (n=31) at the Saitama Medical Center from July 2012 to November 2018 were evaluated.

RESULTS

Overall response rates (ORRs) were 2.6% (fulvestrant) and 41.9% (palbociclib-fulvestrant) (p<0.001), and clinical benefit rates (CBRs) were 23.1% and 61.3% (p=0.002), respectively. The palbociclib-fulvestrant group had significantly higher CBR and PFS (hazard ratio(HR):0.272, 95% confidence interval(95CI):0.128-0.574 for PFS). Grade 3/4 neutropenia occurred in 80.6% of the palbociclib-fulvestrant group, while febrile neutropenia was not detected.

CONCLUSION

Japanese ER+/HER2- metastatic breast cancer patients tolerated palbociclib-fulvestrant, with significantly improved clinical outcomes.

Should All Patients With HR-Positive HER2-Negative Metastatic Breast Cancer Receive CDK 4/6 Inhibitor As First-Line Based Therapy? A Network Meta-Analysis of Data from the PALOMA 2, MONALEESA 2, MONALEESA 7, MONARCH 3, FALCON, SWOG and FACT Trials

Background: We aim to understand whether all patients with hormonal receptor (HR)-positive (+)/human epidermal growth factor receptor-2 (HER2)-negative (-) metastatic breast cancer (MBC) should receive cyclin D-dependent kinase (CDK) 4/6 inhibitor-based therapy as a first-line approach.

METHODS

A network meta-analysis (NMA) using the Bayesian hierarchical arm-based model, which provides the estimates for various effect sizes, were computed.

RESULTS

First-line treatment options in HR+/HER2- MBC, including CDK 4/6 inhibitors combined with aromatase inhibitors (AIs) or fulvestrant (F), showed a significantly longer progression-free survival (PFS) in comparison with AI monotherapy, with a total of 26% progression risk reduction. In the indirect comparison across the three classes of CDK 4/6 inhibitors and F endocrine-based therapies, the first strategy resulted in longer PFS, regardless of specific CDK 4/6 inhibitor (HR: 0.68; 95% CrI: 0.53-0.87 for palbociclib + AI, HR: 0.65; 95% CrI: 0.53-0.79 for ribociclib + AI, HR: 0.63; 95% CrI: 0.47-0.86 for abemaciclib + AI) and patient's characteristics. Longer PFS was also found in patients with bone-only and soft tissues limited disease treated with CDK 4/6 inhibitors.

CONCLUSIONS

CDK 4/6 inhibitors have similar efficacy when associated with an AI in the first-line treatment of HR+ MBC, and are superior to either F or AI monotherapy, regardless of any other patients or tumor characteristics.

Phosphoproteome Analysis Reveals Estrogen-ER Pathway as a Modulator of mTOR Activity Via DEPTOR

ER-positive breast tumors represent ∼70% of all breast cancer cases. Although their treatment with endocrine therapies is effective in the adjuvant or recurrent settings, the development of resistance compromises their effectiveness. The binding of estrogen to ERα, a transcription factor, triggers the regulation of the target genes (genomic pathway). Additionally, a cytoplasmic fraction of estrogen-bound ERα activates oncogenic signaling pathways such as PI3K/AKT/mTOR (nongenomic pathway). The upregulation of the estrogenic and the PI3K/AKT/mTOR signaling pathways are frequently associated with a poor outcome. To better characterize the connection between these two pathways, we performed a phosphoproteome analysis of ER-positive MCF7 breast cancer cells treated with estrogen or estrogen and the mTORC1 inhibitor rapamycin. Many proteins were identified as estrogen-regulated mTORC1 targets and among them, DEPTOR was selected for further characterization. DEPTOR binds to mTOR and inhibits the kinase activity of both mTOR complexes mTORC1 and mTORC2, but mitogen-activated mTOR promotes phosphorylation-mediated DEPTOR degradation. Although estrogen enhances the phosphorylation of DEPTOR by mTORC1, DEPTOR levels increase in estrogen-stimulated cells. We demonstrated that DEPTOR accumulation is the result of estrogen-ERα-mediated transcriptional upregulation of DEPTOR expression. Consequently, the elevated levels of DEPTOR partially counterbalance the estrogen-induced activation of mTORC1 and mTORC2. These results underscore the critical role of estrogen-ERα as a modulator of the PI3K/AKT/mTOR signaling pathway in ER-positive breast cancer cells. Additionally, these studies provide evidence supporting the use of dual PI3K/mTOR or dual mTORC1/2 inhibitors in combination with endocrine therapies as a first-line treatment option for the patients with ER-positive advanced breast cancer.

A New Genetic Risk Score to Predict the Outcome of Locally Advanced or Metastatic Breast Cancer Patients Treated With First-Line Exemestane: Results From a Prospective Study

INTRODUCTION

Approximately 50% of locally advanced or metastatic breast cancer (MBC) patients treated with first-line exemestane do not show objective response and currently there are no reliable biomarkers to predict the outcome of patients using this therapy. The constitutive genetic background might be responsible for differences in the outcome of exemestane-treated patients. We designed a prospective study to investigate the role of germ line polymorphisms as biomarkers of survival.

PATIENTS AND METHODS

Three hundred two locally advanced or MBC patients treated with first-line exemestane were genotyped for 74 germ line polymorphisms in 39 candidate genes involved in drug activity, hormone balance, DNA replication and repair, and cell signaling pathways. Associations with progression-free survival (PFS) and overall survival (OS) were tested with multivariate Cox regression. Bootstrap resampling was used as an internal assessment of results reproducibility.

RESULTS

Cytochrome P450 19A1-rs10046TC/CC, solute carrier organic anion transporter 1B1-rs4149056TT, adenosine triphosphate binding cassette subfamily G member 2-rs2046134GG, fibroblast growth factor receptor-4-rs351855TT, and X-ray repair cross complementing 3-rs861539TT were significantly associated with PFS and then combined into a risk score (0-1, 2, 3, or 4-6 risk points). Patients with the highest risk score (4-6 risk points) compared with ones with the lowest score (0-1 risk points) had a median PFS of 10 months versus 26.3 months (adjusted hazard ratio [AdjHR], 3.12 [95% confidence interval (CI), 2.18-4.48]; P < .001) and a median OS of 38.9 months versus 63.0 months (AdjHR, 2.41 [95% CI, 1.22-4.79], P = .012), respectively.

CONCLUSION

In this study we defined a score including 5 polymorphisms to stratify patients for PFS and OS. This score, if validated, might be translated to personalize locally advanced or MBC patient treatment and management.

Impact of letrozole versus clomiphene citrate on endometrial receptivity in Iraqi women with polycystic ovarian syndrome

WHAT IS KNOWN AND OBJECTIVES

Letrozole is widely known for its use as an ovulation inductor. This study aims to investigate the effects of letrozole and clomiphene citrate in females with polycystic ovarian syndrome.

METHODS

This is a randomized non-blinded controlled trial study that included 80 infertile females with polycystic ovarian syndrome receiving a standard dose of either clomiphene citrate or letrozole on day 2 of the cycle. An ultrasound was done to examine growth of the follicle, endometrial thickness on days 12-13, and a Doppler study to measure resistance index (RI), pulsatility index and ratio of systolic/diastolic velocity.

RESULTS AND DISCUSSION

The mean levels of dominant follicle and oestradiol were significantly higher in the clomiphene citrate group than in the letrozole group. The letrozole group had a significantly greater endometrial thickness than the clomiphene citrate group. The resistance index and pulsatility index were lower in the letrozole group and in pregnant women than in the clomiphene citrate group and the non-pregnant group.

WHAT IS NEW AND CONCLUSION

The use of letrozole for ovulation induction in polycystic ovarian syndrome patients has a better effect on endometrial receptivity markers when compared to clomiphene citrate.

SEOM clinical guidelines in advanced and recurrent breast cancer (2018)

Although the metastasic breast cancer is still an incurable disease, recent advances have increased significantly the time to progression and the overall survival. However, too much information has been produced in the last 2 years, so a well-based guideline is a valuable document in treatment decision making. The SEOM guidelines are intended to make evidence-based recommendations on how to manage patients with advanced and recurrent breast cancer to achieve the best patient outcomes based on a rational use of the currently available therapies. To assign a level of certainty and a grade of recommendation the United States Preventive Services Task Force guidelines methodology was selected as reference.

Imaging Tumor Proliferation in Breast Cancer: Current Update on Predictive Imaging Biomarkers

Uncontrolled growth is a hallmark of cancer; imaging cell proliferation can provides an early indicator of therapeutic response. This capability is especially well-matched to the emerging cell cycle-specific chemotherapeutics with the goal of identifying patients that benefit from these treatments early in the course of treatment to guide personalized therapy. This article focuses on investigational cell proliferation imaging PET radiotracers to evaluate tumor proliferation in the setting of cell cycle-targeted chemotherapy and endocrine therapy for metastatic breast cancer.