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

Loss of Hormone Receptor Expression after Exposure to Fluid Shear Stress in Breast Cancer Cell Lines

Following metastatic spread, many hormone receptor positive (HR+) patients develop a more aggressive phenotype with an observed loss of the HRs estrogen receptor (ER) and progesterone receptor (PR). During metastasis, breast cancer cells are exposed to high magnitudes of fluid shear stress (FSS). Unfortunately, the role for FSS on the regulation of HR expression and function during metastasis is not fully understood. This study was designed to elucidate the impact of FSS on HR+ breast cancer. Utilizing a microfluidic platform capable of exposing breast cancer cells to FSS that mimics in situ conditions, we demonstrate the impact of FSS exposure on representative HR+ breast cancer cell lines through protein and gene expression analysis. Proteomics results demonstrated that 540 total proteins and 1473 phospho-proteins significantly changed due to FSS exposure and pathways of interest included early and late estrogen response. The impact of FSS on response to 17β-estradiol (E2) was next evaluated and gene expression analysis revealed repression of ER and E2-mediated genes (PR and SDF1) following exposure to FSS. Western blot demonstrated enhanced phosphorylation of mTOR following exposure to FSS. Taken together, these studies provide initial insight into the effects of FSS on HR signaling in metastatic breast cancer.

Real-World Experience among Elderly Metastatic Breast Cancer Patients Treated with CDK4/6 Inhibitor-Based Therapy

The largest portion of breast cancer patients diagnosed after 70 years of age present with hormone receptor-positive (HR+) breast cancer subtypes. Cyclin-dependent kinase (CDK) 4/6 inhibitor treatment, in conjunction with endocrine therapy, has become standard-of-care for metastatic HR+ breast cancer. In total, 320 patients with metastatic breast cancer receiving CDK4/6 inhibitor combined with fulvestrant or an aromatase inhibitor were enrolled in an ongoing observational study or were included in an IRB-approved retrospective study. All patients receiving CDK4/6 inhibitor-based therapy that were ≥70 years of age (n = 111) displayed prolonged progression-free survival (27.6 months) as compared to patients <70 years of age (n = 209, 21.1 months, HR = 1.38, p < 0.05). Specifically, patients receiving a CDK4/6 inhibitor with an aromatase inhibitor who were ≥70 years of age (n = 79) displayed exceptionally prolonged progression-free survival (46.0 months) as compared to patients receiving the same treatment who were <70 years of age (n = 161, 21.8 months, HR = 1.71, p < 0.01). However, patients ≥70 years of age also experienced more frequent adverse responses to CDK4/6 inhibitor-based treatment leading to dose reduction, hold, or discontinuation than the younger cohort (69% and 53%, respectively). Treatment strategies that may decrease toxicity without affecting efficacy (such as dose titration) are worth further exploration.

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.

A network meta-analysis of efficacy and safety for first-line and second/further-line therapies in postmenopausal women with hormone receptor-positive, HER2-negative, advanced breast cancer

BACKGROUND

Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR + /HER2 -) advanced breast cancer is a prevalent subtype among postmenopausal women. Despite the growing number of randomized clinical trials (RCTs) exploring this topic, the efficacy and safety of first-line and second/further-line treatments remain uncertain. Accordingly, our aim was to conduct a comprehensive evaluation of the efficacy and safety of these therapies through network meta-analysis.

METHODS

RCTs were identified by searching Pubmed, Embase, and major cancer conferences. The efficacy of interventions was assessed using the hazard ratios (HRs) of progression-free survival (PFS) and overall survival (OS), while safety was indicated by the incidence of any grade adverse events (AEs), grade 3-5 AEs, AEs leading to treatment discontinuation, and AEs leading to death. Both time-variant HRs fractional polynomial models and time-invariant HRs Cox-proportional hazards models were considered for handling time-to-event data. Safety indicators were analyzed using Bayesian network meta-analysis. Additionally, subgroup analyses were conducted based on patient characteristics.

RESULTS

A total of 41 RCTs (first-line 17, second/further-lines 27) were included in the analysis. For first-line treatment, the addition of Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors to endocrine therapy significantly improved therapeutic efficacy in terms of both PFS and OS, demonstrating the best performance across all mechanisms. Specifically, the combination of Abemaciclib and Letrozole demonstrated the most favorable performance in terms of PFS, while Ribociclib plus Fulvestrant yielded the best outcomes in OS. Incorporating the immune checkpoint inhibitor Avelumab into the regimen with CDK4/6 inhibitors and selective estrogen receptor degraders significantly enhanced both PFS and OS in second-line or later treatments. Regarding safety, endocrine monotherapy performed well. Regarding safety, endocrine monotherapy performed well. There is mounting evidence suggesting that most CDK4/6 inhibitors may demonstrate poorer performance with respect to hematologic AEs. However, additional evidence is required to further substantiate these findings.

CONCLUSIONS

CDK4/6 inhibitors, combined with endocrine therapy, are pivotal in first-line treatment due to their superior efficacy and manageable AEs. For second/further-line treatment, adding immune checkpoint inhibitors to CDK4/6 inhibitors plus endocrine therapy may produce promising results. However, to reduce the results' uncertainty, further trials comparing these novel treatments are warranted.

TRIAL REGISTRATION

Registration number: PROSPERO (CRD42022377431).

Determinants of response to CDK4/6 inhibitors in the real-world setting

Despite widespread use and a known mechanism of action for CDK4/6 inhibitors in combination with endocrine therapy, features of disease evolution and determinants of therapeutic response in the real-world setting remain unclear. Here, a cohort of patients treated with standard-of-care combination regimens was utilized to explore features of disease and determinants of progression-free survival (PFS) and overall survival (OS). In this cohort of 280 patients, >90% of patients were treated with palbociclib in combination with either an aromatase inhibitor (AI) or fulvestrant (FUL). Most of these patients had modified Scarff-Bloom-Richardson (SBR) scores, and ER, HER2, and PR immunohistochemistry. Both the SBR score and lack of PR expression were associated with shorter PFS in patients treated with AI combinations and remained significant in multivariate analyses (HR = 3.86, p = 0.008). Gene expression analyses indicated substantial changes in cell cycle and estrogen receptor signaling during the course of treatment. Furthermore, gene expression-based subtyping indicated that predominant subtypes changed with treatment and progression. The luminal B, HER2, and basal subtypes exhibited shorter PFS in CDK4/6 inhibitor combinations when assessed in the pretreatment biopsies; however, they were not associated with OS. Using unbiased approaches, cell cycle-associated gene sets were strongly associated with shorter PFS in pretreatment biopsies irrespective of endocrine therapy. Estrogen receptor signaling gene sets were associated with longer PFS particularly in the AI-treated cohort. Together, these data suggest that there are distinct pathological and biological features of HR+/HER2- breast cancer associated with response to CDK4/6 inhibitors. Clinical trial registration number: NCT04526587.

Coencapsulation of Gemcitabine and Thymoquinone in Citrem-Phosphatidylcholine Hexosome Nanocarriers Improves In Vitro Cellular Uptake in Breast Cancer Cells

Lyotropic liquid crystalline nanoassemblies (LLCNs) are internally self-assembled (ISA)-somes formed by amphiphilic molecules in a mixture comprising a lipid, stabilizer, and/or surfactant and aqueous media/dispersant. LLCNs are unique nanoassemblies with versatile applications in a wide range of biomedical functions. However, they comprise a nanosystem that is yet to be fully explored for targeted systemic treatment of breast cancer. In this study, LLCNs proposed for gemcitabine and thymoquinone (Gem-TQ) co-delivery were prepared from soy phosphatidylcholine (SPC), phytantriol (PHYT), or glycerol monostearate (MYVR) in optimized ratios containing a component of citric and fatty acid ester-based emulsifier (Grinsted citrem) or a triblock copolymer, Pluronic F127 (F127). Hydrodynamic particle sizes determined were below 400 nm (ranged between 96 and 365 nm), and the series of nanoformulations displayed negative surface charge. Nonlamellar phases identified by small-angle X-ray scattering (SAXS) profiles comprise the hexagonal, cubic, and micellar phases. In addition, high entrapment efficiency that accounted for 98.3 ± 0.1% of Gem and 99.5 ± 0.1% of TQ encapsulated was demonstrated by the coloaded nanocarrier system, SPC/citrem/Gem-TQ hexosomes. Low cytotoxicity of SPC-citrem hexosomes was demonstrated in MCF10A cells consistent with hemo- and biocompatibility observed in zebrafish (Danio rerio) embryos for up to 96 h postfertilization (hpf). SPC/citrem/Gem-TQ hexosomes demonstrated IC50 of 24.7 ± 4.2 μM in MCF7 breast cancer cells following a 24 h treatment period with the moderately synergistic interaction between Gem and TQ retained (CI = 0.84). Taken together, biocompatible SPC/citrem/Gem-TQ hexosomes can be further developed as a multifunctional therapeutic nanodelivery approach, plausible for targeting breast cancer cells by incorporation of targeting ligands.

Histology-based survival outcomes in hormone receptor-positive metastatic breast cancer treated with targeted therapies

The addition of targeted therapies (TT) to endocrine therapy (ET) has improved the outcomes of patients with HR-positive, HER2-negative metastatic breast cancer (mBC). However, it is unknown whether patients with invasive lobular carcinoma (ILC) or mixed invasive ductal and lobular carcinoma (mixed) histologies experience the same magnitude of benefit from this therapy as those with invasive ductal carcinoma (IDC). We aim to determine whether patients with IDC, ILC, and mixed HR+/HER2- mBC derive similar benefit from the addition of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is), mammalian target of rapamycin inhibitor (mTORi), and phosphoinositide 3-kinase inhibitor (PI3Ki) to ET in HR+/HER2- mBC. We conducted an observational, population-based investigation using data from the MD Anderson prospectively collected database. We conducted a histology-based analysis of progression-free survival (PFS) and overall survival (OS) durations in 3784 patients with HR+/HER2- mBC who were treated with TT plus ET between January 1, 2010, and December 31, 2021. Out of the 3784 patients, 2975 were included in the final analysis. Of these, 2249 received CDK4/6is (81% IDC, 15% ILC, and 4% mixed), 1027 received everolimus (82% IDC, 14% ILC, and 4% mixed) and 49 received alpelisib (81% IDC and 19% ILC). The addition of targeted therapy to ET did not result in statistically significant differences in PFS or OS duration among patients with IDC, ILC, and mixed HR+/HER2- mBC. We concluded that for patients with HR+/HER2- mBC, the addition of TT to ET leads to a similar magnitude of benefit, irrespective of histology.

[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.