Safety of adjuvant endocrine therapies in hormone receptor-positive early breast cancer

Dual-target inhibitors based on ERα: Novel therapeutic approaches for endocrine resistant breast cancer

Estrogen receptor alpha (ERα), a nuclear transcription factor, is a well-validated therapeutic target for more than 70% of all breast cancers (BCs). Antagonizing ERα either by selective estrogen receptor modulators (SERMs) or selective estrogen receptor degraders (SERDs) forms the foundation of endocrine therapy and has achieved great success in the treatment of ERα positive (ERα+) BCs. Unfortunately, despite initial effectiveness, endocrine resistance eventually emerges in up to 30% of ERα+ BC patients and remains a significant medical challenge. Several mechanisms implicated in endocrine resistance have been extensively studied, including aberrantly activated growth factor receptors and downstream signaling pathways. Hence, the crosstalk between ERα and another oncogenic signaling has led to surge of interest to develop combination therapies and dual-target single agents. This review briefly introduces the synergisms between ERα and another anticancer target and summarizes the recent advances of ERα-based dual-targeting inhibitors from a medicinal chemistry perspective. Accordingly, their rational design strategies, structure-activity relationships (SARs) and biological activities are also dissected to provide some perspectives on future directions for ERα-based dual target drug discovery in BC therapy.

Therapeutic impacts of microRNAs in breast cancer by their roles in regulating processes involved in this disease

Breast cancer is the most common cancer in women around the world. So far, many attempts have been made to treat this disease, but few effective treatments have been discovered. In this work, we reviewed the related articles in the limited period of time, 2000-2016, through search in PubMed, Scopus database, Google Scholar, and psychology and psychiatry literature (PsycINFO). We selected the articles about the correlation of microRNAs (miRNAs) and breast cancer in the insight into therapeutic applicability from mentioned genetics research databases. The miRNAs as an effective therapy for breast cancer was at the center of our attention. Hormone therapy and chemotherapy are two major methods that are being used frequently in breast cancer treatment. In the search for an effective therapy for breast cancer, miRNAs suggest a promising method of treatment. miRNAs are small, noncoding RNAs that can turn genes on or off and can have critical roles in cancer treatment; therefore, in the near future, usage of these biological molecules in breast cancer treatment can be considered a weapon against most common cancer-related concerns in women. Here, we discuss miRNAs and their roles in various aspects of breast cancer treatment to help find an alternative and effective way to treat or even cure this preventable disease.

Navigating the Challenges of Endocrine Treatments in Premenopausal Women with ER-Positive Early Breast Cancer

Endocrine therapy is a key component of adjuvant treatment for premenopausal patients with endocrine-responsive tumors. It is commonly well tolerated, although side effects are a main concern in the selection of treatment options. Tamoxifen is still considered an adequate endocrine therapy in a large group of premenopausal patients (e.g. lower-risk patient, presence of co-morbidities, patient preference). Results of the SOFT and TEXT trials addressing new adjuvant endocrine treatment options in premenopausal patients were recently presented. Overall, in the SOFT study the premenopausal population did not benefit from the addition of ovarian function suppression (OFS). Nevertheless, for women at sufficient risk of recurrence to receive adjuvant chemotherapy and who maintained premenopausal estradiol, the addition of OFS to tamoxifen reduced the risk of recurrence. The magnitude of the effect was larger in younger patients. Moreover, in the SOFT and TEXT trials, adjuvant treatment with exemestane plus OFS, as compared with tamoxifen plus OFS, significantly improved disease-free survival, breast cancer-free interval and distant disease-free survival. However, premenopausal patients include heterogeneous subsets of women and tumors where costs and benefits of adjuvant endocrine therapy should be properly weighted. Issues specific for premenopausal patients, related to desire for pregnancy, family planning, safety, quality of life and subjective side effects, should be a priority in the therapeutic algorithm. Therefore, selecting the best-tolerated agent can enhance adherence to therapies and reduce the impact on quality of life and health status for these younger patients.

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.

Early discontinuation of endocrine therapy for breast cancer: who is at risk in clinical practice?

PURPOSE

Despite evidence supporting at least five years of endocrine therapy for early breast cancer, many women discontinue therapy early. We investigated the impact of initial therapy type and specific comorbidities on discontinuation of endocrine therapy in clinical practice.

METHODS

We identified women in a population-based cohort with a diagnosis of early breast cancer and an incident dispensing of anastrozole, letrozole or tamoxifen from 2003-2008 (N = 1531). Pharmacy and health service data were used to determine therapy duration, treatment for pre-existing and post-initiation comorbidities (anxiety, depression, hot flashes, musculoskeletal pain, osteoporosis, vaginal atrophy), demographic and other clinical characteristics. Time to discontinuation of initial, and any, endocrine therapy was calculated. Cox regression determined the association of different characteristics on early discontinuation.

RESULTS

Initial endocrine therapy continued for a median of 2.2 years and any endocrine therapy for 4.8 years. Cumulative probability of discontinuing any therapy was 17% after one year and 58% by five years. Initial tamoxifen, pre-existing musculoskeletal pain and newly-treated anxiety predicted shorter initial therapy but not discontinuation of any therapy. Early discontinuation of any therapy was associated with newly-treated hot flashes (HR = 2.1, 95% CI = 1.3-3.3), not undergoing chemotherapy (HR = 1.4, 95% CI = 1.1-1.8) and not undergoing mastectomy (HR = 1.5, 95% CI = 1.2-1.8).

CONCLUSIONS

Less than half of women completed five years of endocrine therapy. Women at greatest risk of stopping any therapy early were those with newly-treated hot flashes, no initial chemotherapy, or no initial mastectomy. This suboptimal use means that the reductions in recurrence demonstrated in clinical trials may not be realised in practice.

Worry about cancer progression and low perceived social support: implications for quality of life among early-stage breast cancer patients

BACKGROUND

Worry about cancer progression and perceived social support can affect cancer survivors' quality of life (QOL).

METHODS

In 480 early-stage breast cancer survivors, we examined how worry about cancer progression and perceived social support 6 months after definitive surgery were associated with QOL (RAND 36-item Health Survey) at 6-, 12-, and 24-month follow-up.

RESULTS

At 6 months post-surgery, higher worry was associated with worse QOL for five of eight subscales. Lower social support was associated with worse QOL for four subscales. The negative effects of worry and limited social support dissipated for four subscales (worry) and two subscales (social support) by 12-month follow-up and for all subscales by 24-month follow-up. Social support at 6 months moderated the relationship between T2 worry and T4 emotional well-being; post hoc tests did not clarify the nature of the interaction.

CONCLUSION

Early-stage breast cancer survivors who worry about cancer progression and/or have low social support may experience lower levels of QOL that can take several months to resolve.

Estrogen receptor testing and 10-year mortality from breast cancer: A model for determining testing strategy

Background:

The use of adjuvant tamoxifen therapy in the treatment of estrogen receptor (ER) expressing breast carcinomas represents a major advance in personalized cancer treatment. Because there is no benefit (and indeed there is increased morbidity and mortality) associated with the use of tamoxifen therapy in ER-negative breast cancer, its use is restricted to women with ER expressing cancers. However, correctly classifying cancers as ER positive or negative has been challenging given the high reported false negative test rates for ER expression in surgical specimens. In this paper I model practice recommendations using published information from clinical trials to address the question of whether there is a false negative test rate above which it is more efficacious to forgo ER testing and instead treat all patients with tamoxifen regardless of ER test results.

Methods:

I used data from randomized clinical trials to model two different hypothetical treatment strategies: (1) the current strategy of treating only ER positive women with tamoxifen and (2) an alternative strategy where all women are treated with tamoxifen regardless of ER test results. The variables used in the model are literature-derived survival rates of the different combinations of ER positivity and treatment with tamoxifen, varying true ER positivity rates and varying false negative ER testing rates. The outcome variable was hypothetical 10-year survival.

Results:

The model predicted that there will be a range of true ER rates and false negative test rates above which it would be more efficacious to treat all women with breast cancer with tamoxifen and forgo ER testing. This situation occurred with high true positive ER rates and false negative ER test rates in the range of 20-30%.

Conclusions:

It is hoped that this model will provide an example of the potential importance of diagnostic error on clinical outcomes and furthermore will give an example of how the effect of that error could be modeled using real-world data from clinical trials.

17α-ethynyl-5α-androstane-3α, 17β-diol treatment of MNU-induced mammary cancer in rats

N-methyl-N-nitrosourea (MNU) induces estrogen-dependent mammary tumors in female Lewis rats. We explored the antineoplastic activity of a synthetic androstane derivative, 17α-ethynyl-5α-androstane-3α, 17β-diol (HE3235), as a single agent or in combination with docetaxel compared to tamoxifen, anastrazole, and docetaxel monotherapies against MNU-induced mammary tumors in female Lewis rats. Treatment with HE3235 alone rapidly reduced tumor burden, similar in effect to tamoxifen and anastrozole. The combination of HE3235 with docetaxel was more effective than any single agent, although without apparent toxicity. Only HE3235 or HE3235 plus docetaxel continued to suppress tumor growth after cessation of treatment. HE3235 treatment increased immunohistochemical markers of apoptosis and expression of proapoptotic genes and estrogen receptor beta and decreased expression of antiapoptotic genes, androgen receptor, and estrogen receptor alpha. These data warrant clinical investigation of HE3235 for breast cancer treatment.

Incidence and management of arthralgias in breast cancer patients treated with aromatase inhibitors in an outpatient oncology clinic

Purpose:

Aromatase inhibitors (AIs) are routinely used as first-line adjuvant treatment of breast cancer in postmenopausal women with hormone receptor positive tumors. The current recommended length of treatment with an AI is 5 years. Arthralgias have been frequently cited as the primary reason for discontinuation of AI therapy. Various treatment strategies are proposed in literature, but a standardized treatment algorithm has not been established. The initial purpose of this study was to describe the incidence and management of AI-induced arthralgias in patients treated at Kellogg Cancer Center (KCC). Further evaluation led to the development and the implementation of a treatment algorithm and electronic medical record (EMR) documentation tools.

Methods:

The retrospective chart review included 206 adult patients with hormone receptor positive breast cancer who were receiving adjuvant therapy with an AI. A multidisciplinary treatment team consisting of pharmacists, collaborative practice nurses, and physicians met to develop a standardized treatment algorithm and corresponding EMR documentation tool. The treatment algorithm and documentation tool were developed after the study to better monitor and proactively treat patients with AI-induced arthralgias.

Results/conclusions:

The overall incidence of arthralgias at KCC was 48% ( n = 98/206). Of these patients, 32% were documented as having arthralgias within the first 6 months of therapy initiation. Patients who reported AI-induced arthralgias were younger than patients who did not report AI-induced arthralgias (61 vs. 65 years, p = 0.002). There was no statistical difference in the incidence of arthralgias in patients with a history of chemotherapy (including taxane therapy) compared to those who did not receive chemotherapy ( p = 0.352). Of patients presenting with AI-induced arthralgias, 41% did not have physician-managed treatment documented in the EMR. A standardized treatment algorithm and electronic chart documentation tools were then developed by the multidisciplinary team.

Adherence to oral endocrine treatments in women with breast cancer: can it be improved?

There is a perception that women on oral endocrine treatments for oestrogen receptor-positive breast cancer will be adherent to these medicines, as they are facing a serious life-threatening disease, and the oral endocrine treatments are effective, easy to use and generally well tolerated. This is not in fact the case, and this is the basis of the first half of this review. The second half is of whether the changes/interventions to 'improve' adherence do actually increase adherence to the oral endocrine medicines. The review shows that better outcomes are achieved with good adherence to endocrine treatments in breast cancer. The rates of adherence to endocrine treatments range between 15 and 50%, and are influenced by a large number of factors (e.g. adverse effects, lack of belief in treatment, psychological problems and poor patient-health care provider relationship). Interventions to minimise the adverse effects have been used in an attempt to improve the adherence to the endocrine treatment therapies, but it is not known whether these do actually improve adherence. Similar, it has been assumed that interventions by health professionals (doctors, nurses and pharmacists) will improve the adherence, but this has not been tested. In conclusion, in women with breast cancer, we know there is a problem with adherence. There are also many approaches and suggestions about how to improve adherence to the oral endocrine treatments, but none of these approaches/suggestions have been scientifically tested, and they need to be.

Aromatase inhibitor therapy: toxicities and management strategies in the treatment of postmenopausal women with hormone-sensitive early breast cancer

Aromatase inhibitors (AIs) have been shown to reduce the risk of breast cancer recurrence and are widely used today as adjuvant therapy in women with early stage endocrine-responsive breast cancer. Aromatase inhibitors may be prescribed as initial hormonal therapy, sequentially following 2-3 years of tamoxifen, or as extended adjuvant therapy (following 5 years of tamoxifen). Aromatase inhibitors are generally well tolerated; however, certain side effects, particularly arthralgia/musculoskeletal symptoms and gynecologic effects, may result in poor adherence to treatment. Patients receiving adjuvant therapy with an AI should be counseled regarding possible side effects and the importance of completing treatment. Interventions to ameliorate side effects should be individualized based on symptoms, comorbid conditions, and pre-existing therapies. In addition, bone and cardiovascular health should be monitored during AI therapy. Prompt therapeutic management of common side effects associated with AIs may provide patients with the opportunity to receive the full benefit of their adjuvant hormonal treatment while minimizing toxicity.

Benefits and adverse effects of endocrine therapy

Endocrine-responsive tumors that are small and without nodal involvement (i.e. tumors classified as pT1 pN0) are a heterogeneous group of tumors that are associated with a low risk of relapse in the majority of the cases. Therefore, the costs and benefits of adjuvant endocrine therapy should be carefully considered within this subgroup of patients. Treatment decisions should take into consideration co-morbidities as well as the presence of other classical risk factors such as HER2 overexpression or extensive peritumoral vascular invasion. Tamoxifen or tamoxifen plus ovarian function suppression should be considered as proper endocrine therapies in premenopausal patients. Ovarian function suppression alone or ovarian ablation might also be considered adequate in selected patients (e.g. very low-risk patients, in the presence of co-morbidities or patient preference). An aromatase inhibitor should form part of standard endocrine therapy for most postmenopausal women with receptor-positive breast cancer, although patients at low risk or with co-morbid musculoskeletal or cardiovascular risk factors may be considered suitable for tamoxifen alone. Tailored endocrine treatments should be considered in patients with endocrine-responsive tumors classified as pT1 pN0. Issues focusing on safety, quality of life and subjective side effects should be routinely discussed.