Anastrozole versus tamoxifen as adjuvant therapy for Japanese postmenopausal patients with hormone-responsive breast cancer: efficacy results of long-term follow-up data from the N-SAS BC 03 trial

Adjuvant endocrine treatment strategies for non-metastatic breast cancer: a network meta-analysis

Background

Multiple trials have evaluated escalation strategies of endocrine therapy for early breast cancer, including ovarian function suppression (OFS) and aromatase inhibitors (AI) in premenopausal patients and extended endocrine therapy. However, several aspects remain controversial due to the heterogeneity of study designs and lack of statistical power in relevant subgroups. We aimed to investigate the optimal endocrine therapy strategy.

Methods

A systematic literature search was performed and last updated in August 2024 to identify randomized controlled trials (RCT) evaluating endocrine treatment strategies for hormone receptor positive breast cancer. A network meta-analysis with a frequentist framework using random-effects model was used to pool direct and indirect evidence. In addition, an extracted individual patient data meta-analysis was conducted to estimate the absolute differences between treatments. Study endpoints were disease-free survival (DFS), overall survival (OS), and safety. PROSPERO: CRD42023447979.

Findings

A total of 37 RCT that had enrolled 107,684 patients were included in the study. During the first five years, OFS + AI was the most effective strategy in premenopausal women, while AI or switch strategy showed the better efficacy results in postmenopausal ones. Following five years of tamoxifen, continuation with five additional years of AI was associated with improved 8-year DFS (85.8%) compared to no extended therapy (78.1%) or five additional years of tamoxifen (81.0%). Following five years of AI or switch strategy, extended treatment with AI improved DFS (Hazard Ratio = 0.81, 95% Confidence Interval 0.73-0.90).

Interpretation

This study provides information regarding the optimal endocrine treatment strategies for patients with resected hormone receptor positive early breast cancer.

Funding

None.

Efficacy and Safety of Initial 5 Years of Adjuvant Endocrine Therapy in Postmenopausal Hormone Receptor-Positive Breast Cancer: A Systematic Review and Network Meta-Analysis

Purpose: To identify the optimal initial 5 years of adjuvant endocrine therapy for hormone receptor-positive postmenopausal early breast cancer (EBC) patients.

Methods: We conducted a systematic search of the PubMed, Web of Science, and EMBASE to obtain relevant studies published between January 2000 and January 2022. Randomized clinical trials assessing the efficacy and safety of initial 5 years of adjuvant endocrine therapy were included. The primary outcomes were disease-free survival and overall survival and the secondary outcome was severe adverse effects (SAEs). A Bayesian network meta-analysis was carried out to indirectly compare all regimens and the value of surface under the cumulative ranking curve (SUCRA) was used to obtain rankings.

Results: Eleven studies with 49,987 subjects were included. For DFS, exemestane (EXE) [hazard ratio (HR) 0.91, 95% confidence interval (95%CI) 0.87–0.96], anastrozole (ANA) (0.94, 0.90–0.97), letrozole (LET) (0.93, 0.89–0.97), tamoxifen (TAM) followed by EXE (0.91, 0.87–0.96), and TAM followed by ANA (0.92, 0.87–0.98) were more favorable than TAM, with TAM followed by EXE ranking as the first of SUCRA. For OS, only TAM followed by ANA showed significant superiority than TAM (HR 0.91, 95%CI 0.86–0.97) and ranked as the first of SUCRA. For SAEs, EXE (HR 1.72, 95%CI 1.04–2.98), ANA (1.58, 1.03–2.43), and LET (1.63, 1.02–2.57) showed greater associations with bone fracture than TAM. However, no significant difference in the incidences of cardiac events, thromboembolic events, and cerebrovascular events was found among all comparisons.

Conclusion: The sequential use of aromatase inhibitors, which has the best curative effects and relatively mild side effects, may be the optimal treatment mode for hormone receptor-positive postmenopausal EBC patients. In addition, the three kinds of aromatase inhibitors achieved roughly equal efficacy, but caused different types of SAEs.

Systematic Review Registration: [website], identifier [registration number].

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.

Evolution in the risk of adverse events of adjuvant endocrine therapy in postmenopausal women with early-stage breast cancer

BACKGROUND

Adjuvant endocrine therapy is a gold standard in early-stage, hormone receptor positive breast cancer. In postmenopausal women, aromatase inhibitors (AIs) are associated with improved outcome compared to tamoxifen monotherapy. Differences in the toxicity profiles of these drugs are described; however, little is known about whether the risk of adverse events changes over time.

METHODS

Sequential reports of large, randomized, adjuvant endocrine therapy trials comparing AIs to tamoxifen were reviewed. Data on pre-specified adverse events were extracted including cardiovascular events, bone fractures, cerebrovascular disease, endometrial cancer, secondary malignancies excluding breast cancer, venous thrombosis and death without recurrence. Odds ratios (ORs) were calculated for each adverse event at each time over the course of follow-up. The change in the ORs for adverse events over time was evaluated using weighted linear regression.

RESULTS

Analysis included 21 reports of 7 trials comprising 30,039 patients and reporting outcomes between 28 and 128 months of follow-up. Compared to tamoxifen, AIs use was associated with a significant reduction in the magnitude of increased odds of bone fracture over time (β = - 0.63, p = 0.013). There was a non-significant decrease in the magnitude of reduced odds of secondary malignancies over time (β = 0.448, p = 0.094). The differences in other toxicity profiles between AIs and tamoxifen did not change significantly over time.

CONCLUSIONS

The increased risk of bone fractures associated with adjuvant AIs falls over time and after discontinuation of treatment. Differences in other toxicities between AIs and tamoxifen do not change significantly over time including a persistently elevated risk of cardiovascular events.

In vitro schistosomicidal activity of tamoxifen and its effectiveness in a murine model of schistosomiasis at a single dose

Schistosomiasis is a neglected tropical disease affecting 220 million people worldwide. Praziquantel has proven to be effective against this parasitic disease, though there are increasing concerns regarding tolerance/resistance that calls for new drugs. Repurposing already existing and well-known drugs has been a desirable approach since it reduces time, costs, and ethical concerns. The anti-cancer drug tamoxifen (TAM) has been used worldwide for several decades to treat and prevent breast cancer. Previous reports stated that TAM affects Schistosoma hormonal physiology; however, no controlled schistosomicidal in vivo assays have been conducted. In this work, we evaluated the effect of TAM on female and male Schistosoma mansoni morphology, motility, and egg production. We further assessed worm survival and egg production in S. mansoni-infected mice. TAM induced morphological alterations in male and female parasites, as well as in eggs in vitro. Furthermore, in our in vivo experiments, one single dose of intraperitoneal TAM citrate reduced the total worm burden by 73% and led to a decrease in the amount of eggs in feces and low percentages of immature eggs in the small intestine wall. Eggs obtained from TAM citrate-treated mice were reduced in size and presented hyper-vacuolated structures. Our results suggest that TAM may be repurposed as a therapeutic alternative against S. mansoni infections.

Novel evaluation scale for QOL (QOL-ACD-BP) in preoperative chemotherapy for breast cancer

PURPOSE

Quality-of-life (QOL) has been reported to affect the prognosis of many types of cancer, and several studies used various QOL assessment tools to determine the relationship between QOL and cancer prognosis. In this study, QOL-Questionnaire for Cancer Patients Treated with Anti-Cancer Drugs-the Breast (QOL-ACD-B) was modified to be suitable for preoperative chemotherapy (POC) and was named the QOL-ACD-BP.

METHODS

A total of 300 patients were treated with POC after being diagnosed with breast cancer between February 2007 and December 2016 at our institute. We evaluated novel evaluation scale for QOL (QOL-ACD-BP) before and after POC in a retrospective manner.

RESULTS

In the multivariate analysis with overall survival, the high QOL before [p = 0.048, hazard ratio (HR) 0.441] or after POC (p = 0.030, HR 0.273) was an independent factor.

CONCLUSION

Our study shows that QOL after POC may also affect prognosis and supported the importance of maintaining QOL in cancer treatment. In patients with breast cancer treated with POC, QOL-ACD-BP, which is a new QOL evaluation index, was found to be a useful tool for predicting the patients' prognosis.

A meta-analysis of randomized controlled trials comparing the efficacy and safety of anastrozole versus tamoxifen for breast cancer

Whether anastrozole has superior effects to tamoxifen for breast cancer remains controversial. Therefore, we conducted this meta-analysis of randomized controlled trials (RCTs) to compare the efficacy and safety of anastrozole versus tamoxifen as adjuvant therapy in breast cancer. A systematic literature search of PubMed, Web of Science, Embase, and Cochrane library were performed to evaluate the survival benefits and toxicity profiles of patients with breast cancer who were treated with anastrozole or tamoxifen. The main outcome measures included disease-free survival (DFS), recurrence-free survival (RFS), overall survival (OS), overall response rate (ORR), and adverse events. Hazard ratios (HRs) or risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a fixed-effects model or random-effects model. Nine RCTs with a total of 15,300 patients met the inclusion criteria and were included in this meta-analysis. Pooled estimates suggested that, anastrozole was associated with a significantly improvement in DFS (HR=0.72, 95%CI: 0.55-0.94; P=0.016), and ORR (RR=1.21, 95% CI: 1.05-1.39; P=0.009) than tamoxifen. But it did not prolong OS (HR=0.96, 95%CI: 0.77-1.21; P=0.751). Compared with tamoxifen, anastrozole induced a higher incidence of arthralgia (RR=1.55, 95%CI: 1.20-1.99; P=0.001) and bone pain (RR=1.31, 95%CI: 1.05-1.62; P=0.015), as well as a lower incidence of vaginal bleeding (RR=0.51, 95%CI: 0.28-0.93; P=0.029), vaginal discharge (RR=0.31, 95%CI: 0.12-0.82; P=0.017), and thromboembolic events (RR=0.39, 95%CI: 0.28-0.55; P<0.001). Based on the current evidence, patients with breast cancer would benefit from the anastrozole treatment.

Suppression of PTEN/AKT signaling decreases the expression of TUBB3 and TOP2A with subsequent inhibition of cell growth and induction of apoptosis in human breast cancer MCF-7 cells via ATP and caspase-3 signaling pathways

The aim of the present study was to evaluate the effects of PTEN/AKT signaling on TUBB3 and TOP2A expression and on the subsequent cell growth of human breast cancer MCF-7 cells. We found that the disease-free survival (DFS) and overall survival (OS) of breast cancer patients with TUBB3‑positive tumors were lower than these rates in the patients with TUBB3-negative tumors. Meanwhile, DFS and OS of breast cancer patients with TOP2A-positive tumors were also lower than these rates in patients with TOP2A-negative tumors. Suppression of PTEN reduced the protein expression of TUBB3 and TOP2A in MCF-7 cells. Suppression of PTEN also reduced cell proliferation and induced apoptosis and caspase-3 activity in MCF-7 cells. Moreover, an increase in ATP also reduced TUBB3 and TOP2A protein expression, reduced cell proliferation and induced apoptosis and caspase-3 activity in the MCF-7 cells following suppression of PTEN. Suppression of phosphorylation-AKT (p-AKT) reduced the protein expression of TUBB3 and TOP2A in the MCF-7 cells. Suppression of p-AKT also reduced cell proliferation and induced apoptosis and caspase-3 activity in the MCF-7 cells. Then, ATP also reduced TUBB3 and TOP2A protein expression, reduced cell proliferation and induced apoptosis and caspase-3 activity in MCF-7 cells following suppression of p-AKT. These results suggest that PTEN/AKT signaling affects the expression of TUBB3 and TOP2A reducing cell growth and inducing apoptosis of human breast cancer MCF-7 cells through ATP and caspase-3 signaling pathways. TUBB3 and TOP2A may be promising prognostic markers for the efficacy of adjuvant cisplatin-based chemotherapy.

Endocrine resistance in breast cancer--An overview and update

Tumors that express detectable levels of the product of the ESR1 gene (estrogen receptor-α; ERα) represent the single largest molecular subtype of breast cancer. More women eventually die from ERα+ breast cancer than from either HER2+ disease (almost half of which also express ERα) and/or from triple negative breast cancer (ERα-negative, progesterone receptor-negative, and HER2-negative). Antiestrogens and aromatase inhibitors are largely indistinguishable from each other in their abilities to improve overall survival and almost 50% of ERα+ breast cancers will eventually fail one or more of these endocrine interventions. The precise reasons why these therapies fail in ERα+ breast cancer remain largely unknown. Pharmacogenetic explanations for Tamoxifen resistance are controversial. The role of ERα mutations in endocrine resistance remains unclear. Targeting the growth factors and oncogenes most strongly correlated with endocrine resistance has proven mostly disappointing in their abilities to improve overall survival substantially, particularly in the metastatic setting. Nonetheless, there are new concepts in endocrine resistance that integrate molecular signaling, cellular metabolism, and stress responses including endoplasmic reticulum stress and the unfolded protein response (UPR) that provide novel insights and suggest innovative therapeutic targets. Encouraging evidence that drug combinations with CDK4/CDK6 inhibitors can extend recurrence free survival may yet translate to improvements in overall survival. Whether the improvements seen with immunotherapy in other cancers can be achieved in breast cancer remains to be determined, particularly for ERα+ breast cancers. This review explores the basic mechanisms of resistance to endocrine therapies, concluding with some new insights from systems biology approaches further implicating autophagy and the UPR in detail, and a brief discussion of exciting new avenues and future prospects.