Efficacy of endocrine therapy in relation to progesterone receptor and Ki67 expression in advanced breast cancer

The Impact of Progesterone Receptor Status on Survival Outcomes in Metastatic Breast Cancer Patients Treated with First-Line CDK4/6 Inhibitors

BACKGROUND/OBJECTIVES

CDK4/6 inhibitors have changed the landscape of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (BC) management. It is essential to identify predictive and prognostic factors for the efficacy of CDK4/6 inhibitors. We aimed to investigate the differences in characteristics and outcomes of patients receiving first-line CDK4/6 inhibitors according to PgR status.

METHODS

This multicenter retrospective study included 351 patients treated with first-line CDK 4/6 inhibitors for HR-positive/HER2-negative metastatic BC. Patients were categorized based on their PgR expression levels, including the PgR-low (<20%) and PgR-high (≥20%) groups, and baseline characteristics, treatment responses, and survival outcomes were analyzed.

RESULTS

The median age was 57 years (range: 26-85). A total of 99 patients were premenopausal, and 252 patients were postmenopausal. There were 115 (32.8%) patients in the PgR-low group, while 236 (67.2%) were in the PgR-high group. The majority of patients (56.7%) presented with de novo metastatic disease. Visceral metastases presented in 44.2% of patients. Low PgR expression was significantly associated with lower estrogen receptor levels (p = 0.031), elevated Ki-67 levels (p = 0.002), a higher incidence of visceral metastases (p = 0.035), and recurrent disease (p = 0.019). In the multivariate analysis, low PgR expression was a significant independent predictor of worse progression-free survival (PFS) and overall survival (OS).

CONCLUSIONS

We demonstrated that low PgR expression is independently and significantly correlated with shorter PFS and OS. These findings support low PgR expression as a valuable prognostic biomarker in metastatic BC patients treated with first-line CDK4/6 inhibitors.

Clinically Significant BRCA1 and BRCA2 Germline Variants in Breast Cancer-A Single-Center Experience

BACKGROUND

Conditions associated with BRCA1/2 pathogenic (PVs) or likely pathogenic variants (LPVs) are often severe. The early detection of carrier status is ideal, as it provides options for effective case management.

MATERIALS AND METHODS

The study involved 58 patients with a personal and familial history of breast cancer (BC) who underwent genetic testing at the Regional Centre for Medical Genetics Dolj over a three-year period. An immunohistochemical panel (HER2, ER, PR, and Ki-67) was used to define the molecular subtypes of breast tumors. The AmpliSeq for Illumina BRCA Panel was used to evaluate germline variants in the BRCA1 and BRCA2 genes in patients with BC. The χ2 test and Fisher's exact test were used to compare the different parameters studied.

RESULTS

Our findings revealed that 15.5% of the patients carried either BRCA1 or BRCA2 PVs or LPVs. BRCA1 carriers had aggressive tumors whereas BRCA2 carriers had rather low-grade tumors.

CONCLUSIONS

The study revealed that PVs in both BRCA genes have a significant frequency among BC patients in our region, and BRCA1 carriers tend to develop more aggressive tumors than carriers of BRCA2 PVs and patients with no germline PVs in either of the two genes. These observations could provide new epidemiologic data for this disease in our region and contribute further to the development of national screening strategies.

Effect of PR status on the prognosis of advanced ER-high HER2-negative breast cancer patients receiving CDK4/6 inhibitor combined with endocrine as first-line therapy

BACKGROUND

This study was designed to evaluate the effect of progesterone receptor (PR) status on the prognosis of advanced estrogen receptor (ER)-high human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients receiving CDK4/6 inhibitor combined with endocrine as first-line therapy.

METHODS

Advanced ER-high HER2-negative breast cancer patients who were admitted to Harbin Medical University Cancer Hospital and received cyclin-dependent kinase (CDK)4/6 inhibitor combined with endocrine as first-line therapy were included for analysis. Patients were divided into PR-high group (11-100%), PR-low group (1-10%), and PR-negative group (< 1%) according to the expression of PR. Chi-square test was used to analyze the correlation of variables between groups. COX regression analysis were used to analyze the risk factors of survival. Kaplan-Meier survival curve was used to analyze the differences of progression-free survival (PFS) and overall survival (OS) between groups.

RESULTS

Among the 152 patients, 72 were PR-high, 32 were PR-low, and 48 were PR-negative. Compared with PR-negative group, the proportions of disease-free survival (DFS) ≥ 5 years and Ki-67 index ≤ 30% in PR-low group and PR-high group were significant higher. PR-negative patients were more likely to occur first-line progression of disease within 24 months (POD24) than PR-high(P = 0.026). Univariate and multivariate analysis showed that PR-negative and first-line POD24 occurrence were risk factors for survival. Survival curve analysis showed that compared with PR-high group, the PFS and OS were significantly lower in PR-negative group (P = 0.001, P = 0.036, respectively). Patients with first-line POD24 had shorter OS in the overall population as well as in subgroups stratified by PR status.

CONCLUSIONS

PR-negative and first-line POD24 occurrence were risk factors of advanced ER-high HER2-negative breast cancer patients receiving CDK4/6 inhibitor combined with endocrine as first-line therapy. PR-negative patients had shortest PFS and OS. Regardless of PR status, first-line POD24 occurrence predicted shorter OS.

Long-term treatment patterns and survival in metastatic breast cancer by intrinsic subtypes - an observational cohort study in Sweden

Background

Longitudinal, real-world data on the management of metastatic breast cancer is increasingly relevant to understand breast cancer care in routine clinical practice. Yet such data are scarce, particularly beyond second- and third-line treatment strategies. This study, therefore, examined both the long-term treatment patterns and overall survival (OS) in a regional Swedish cohort of female patients with metastatic breast cancer stratified by subtype in routine clinical practice during a recent eight-year period and correlation to current treatment guidelines.

Methods

Consecutive female patients with metastatic breast cancer  clinically managed at Uppsala University Hospital, Uppsala, Sweden, during 2009–2016 and followed until the end of September, 2017 (n = 370) were included and, where possible, classified as having one of five, intrinsic subtypes: Luminal A; Luminal B; human epidermal growth factor receptor 2-positive (HER2+)/ estrogen receptor-positive (ER+); HER2+/estrogen receptor-negative (ER-); or triple negative breast cancer (TNBC). Treatment patterns and OS were estimated by subtype using time-to-event methods.

Results

A total of 352/370 patients with metastatic breast cancer (mean age 67.6 years) could be subtyped: 118 (34%) were Luminal A, 119 (34%) Luminal B, 31 (8%) HER2+/ER-, 38 (11%) HER2+/Luminal, and 46 (13%) TNBC. The median number of metastatic treatment lines was 3. Most patients were on active treatment during follow-up (80% of the observation period), except for patients with TNBC who were on treatment for 60% of the observation time. Overall, 67% of patients died whilst on treatment. Among all patients (n = 370), median OS was 32.5 months (95% CI = 28.2–35.7). The 5-year survival rate was highest for HER2+/Luminal (46%) patients, followed by Luminal B (29%), Luminal A (28%), HER2+/ER- (21%), and TNBC (7%). Increasing age and number of metastatic sites also predicted worse survival.

Conclusions

Metastatic breast cancer patients in Sweden, irrespective of subtype, generally receive active treatment until time of death. Survival varies considerably across subtypes and is also associated with patient characteristics. Regardless of differences in treatment patterns for Luminal A and B patients, long-term OS was the same.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10098-1.

Ki67 and progesterone receptor status predicts sensitivity to palbociclib: a real-world study

Background

Palbociclib combined with endocrine therapy has been approved as a front-line treatment for hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC). A key challenge remains to uncover biomarkers to identify those patients who may benefit from palbociclib treatment.

Methods

We retrospectively analyzed the values of Ki67 and progesterone receptor (PR) as detected by immunohistochemistry in 81 ABC patients with palbociclib and hormone therapy treatment, and evaluated the impact on progression-free survival (PFS).

Results

In the total population, women with Ki67 ≥14% had marginally significantly shorter PFS than those with Ki67 <14% (P=0.062). Patients with Ki67 ≥30% had significantly shorter PFS than those with Ki67 <30% (P=0.048). Meanwhile, PR ≥20% was associated with longer PFS. Moreover, the change of Ki67 or PR from primary tissue to metastatic lesions was related to PFS. As for the hormone therapy subgroup, there were significant associations between Ki67 and PR levels and PFS in the aromatase inhibitors (AIs) subgroup. Patients with Ki67 ≥14% or Ki67 ≥30% had shorter PFS than those with Ki67 <14% or Ki67 <30%, respectively (P=0.024, P<0.001). Additionally, the change of Ki67 or PR from primary tissue to metastatic lesions was related to PFS. When both Ki67 and PR were considered, there were significant differences between the different cohorts. Compared with patients with Ki67 ≥14% and PR <20%, those with Ki67 <14% and PR ≥20% had significantly longer PFS. In addition, patients with Ki67 <30% and PR ≥20% had significantly longer PFS than those with Ki67 ≥30% and PR <20%. Furthermore, in the AI cohort, patients with Ki67 <14% and PR ≥20% had significantly longer PFS than those with Ki67 ≥14% and PR <20%. Women with Ki67 <30% and PR ≥20% had significantly longer PFS than those with Ki67 ≥30% and PR <20%.

Conclusions

The present study indicates that both Ki67 and PR have great impacts on palbociclib and hormone therapy and may contribute to selecting more effective partners for palbociclib.

Ki67 and PR in Patients Treated with CDK4/6 Inhibitors: A Real-World Experience

CDK4/6 inhibitors (CDK4/6i) are recommended in patients with estrogen receptor (ER)-positive, HER2-negative advanced breast cancer (ABC). Up to now, no prognostic biomarkers have been identified in this setting. We retrospectively analyzed the expression of progesterone receptor (PR) and Ki67, assessed by immunohistochemistry, in 71 ABC patients treated with CDK4/6i and analyzed the impact of these markers on progression-free survival (PFS). The majority of patients 63/71 (88.7%) received palbociclib, 4 (5.6%) received ribociclib, and 4 (5.6%) received abemaciclib. A higher median value of Ki67 was observed in cases undergoing second-line treatment (p = 0.047), whereas the luminal B subtype was more prevalent (p = 0.005). In the univariate analysis of the first-line setting, luminal A subtype showed a trend towards a correlation with a longer PFS (p = 0.053). A higher continuous Ki67 value led to a significantly shorter PFS. When the interaction between pathological characteristics and line of treatment was considered, luminal B subtype showed a significantly (p = 0.043) worse outcome (Hazard Ratio (HR) 2.84; 1.03–7.82 95% Confidence Interval (CI)). PFS in patients undergoing endocrine therapy plus CDK4/6i was inversely correlated with Ki67 expression but not with PR, suggesting that tumor proliferation has a greater impact on cell cycle inhibitors combined with endocrine therapy than PR expression.

Impressive long-term response with chemo-endocrine therapy in a premenopausal patient with metastatic breast cancer: A case report

RATIONALE

Patients with, or who develop, metastatic breast cancer have a 5-year relative survival of about 25%. Endocrine therapy clearly improves outcomes in patients with estrogen receptor-positive breast cancer. In the metastatic setting, the primary goal of treatment is to maintain long-term disease control with good quality of life. Rarely, exceptional responders achieve durable disease control, and potential cures cannot be ruled out.

PATIENT CONCERNS

We report the case of a 39-year-old woman with primary breast cancer and associated synchronous bone metastases, who experienced a disease response of 12 years with hormonal therapy as maintenance after first line chemotherapy, with a good toxicity profile.

DIAGNOSIS

The patient was diagnosed with estrogen receptor + human epidermal growth factor receptor 2 (HER2)- metastatic breast cancer with synchronous bone metastases.

INTERVENTIONS

This patient was treated with chemotherapy for 6 cycles as a first-line therapy following by endocrine treatment given as a maintenance therapy.

OUTCOMES

Our patient experienced a progression-free survival >12 years with an exceptionally good quality of life.

LESSONS

Our anecdotal experience highlights the existence of exceptional responders among patients with hormone receptor-positive metastatic breast cancer, who achieve clinical remission and durable disease control with endocrine therapy. Being able to identify these patients could help in the selection of the best treatment option among the many available.

The impact of progesterone receptor expression on prognosis of patients with rapidly proliferating, hormone receptor-positive early breast cancer: a post hoc analysis of the IBIS 3 trial

Background

In the Italian Breast Cancer Intergroup Studies (IBIS) 3 phase III trial, we compared cyclophosphamide, methotrexate, 5-fluorouracil (CMF) alone to sequential epirubicin/CMF regimens in patients with rapidly proliferating early breast cancer (RPEBC). We performed a post hoc analysis in the subgroup of patients with hormone-receptor-positive RPEBC on the prognostic role of progesterone receptor (PgR) status.

Methods

RPEBC was defined by thymidine labeling index (TLI) >3% or grade 3 or S-phase >10% or Ki67 >20%. We analyzed 466 patients with hormone-receptor-positive RPEBC receiving sequential epirubicin/CMF regimens followed by tamoxifen, and for whom the status of ER and PgR was available.

Results

Considering both cut-off values of 10% and 20%, PgR expression was significantly associated with age, menopausal status, and ER expression; HER2 status was associated with PgR status only at a cutoff value of 20% PgR. Upon univariate analysis, tumor size, nodal status, and PgR were significantly associated with disease-free survival (DFS) and overall survival (OS), while age class and local treatment type were associated only with DFS. Patients with PgR <20% showed lower 5- and 10-year DFS [hazard ratio (HR) = 1.48; 95%CI: 1.01-2.18; p = 0.044] and OS (HR = 1.85; 95%CI: 1.08-3.19, p = 0.025) rates compared with patients with PgR ⩾20%. Upon multivariate analysis, only tumor size, nodal status, and PgR were independent prognostic factors.

Conclusions

Our results highlight the independent prognostic relevance of PgR expression in patients with hormone-receptor-positive RPEBC treated with adjuvant chemotherapy and endocrine therapy, where the definition of prognostic subgroups is still a major need.

Review of concepts in therapeutic decision-making in HER2-negative luminal metastatic breast cancer

Purpose

Hormone receptor (HR)-positive, Human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) requires a therapeutic approach that takes into account multiple factors, with treatment being based on anti-estrogen hormone therapy (HT). As consensus documents are valuable tools that assist in the decision-making process for establishing clinical strategies and optimize the delivery of health services, this consensus document has been created with the aim of developing recommendations on cretiera for hormone sensitivity and resistance in HER2-negative luminal MBC and facilitating clinical decision-making.

Methods

This consensus document was generated using a modification of the RAND/UCLA methodology, which included the definition of the project and identification of issues of interest, a non-exhaustive systematic review of the literature, an analysis and synthesis of the scientific evidence, preparation of recommendations, and external evaluation with a panel of 64 medical oncologists specializing in breast cancer.

Results

A Spanish panel of experts reached consensus on 32 of the 32 recommendations/conclusions presented in the first round and were accepted with an approval rate of 100% about definition of metastatic disease not susceptible to local curative treatment, definition of hormone sensitivity and hormone resistance in metastatic luminal disease and therapeutic decision-making.

Conclusion

We have developed a consensus document with recommendations on the treatment of patients with HER2-negative luminal MBC that will help to improve therapeutic benefits.

Evaluation of Androgen Receptor in Relation to Estrogen Receptor (AR/ER) and Progesterone Receptor (AR/PgR): A New Must in Breast Cancer?

Steroid nuclear receptors are known to be involved in the regulation of epithelial-mesenchymal transition process with important roles in invasion and metastasis initiation. Androgen receptor (AR) has been extensively studied, but its role in relation to breast cancer patient prognosis remains to be clarified. AR/ER ratio has been reported to be an unfavorable prognostic marker in early primary breast cancer, but its role in the patients with advanced disease has to be cleared. We retrospectively analyzed ER, PgR, and AR expression on a case series of 159 specimens of primary BC samples by using immunohistochemistry and 89 patients of these had luminal tumors for which AR and ER expression and survival data were available. For twenty-four patients both primary and metastatic tumors were available. A significantly shorter overall survival was observed in primary tumors with AR/PgR ratio ≥ 1.54 (HR = 2.27; 95% CI 1.30-3.97; p = 0.004). Similarly OS was significantly shorter when ER/PgR ratio ≥2 in primary tumors (HR = 1.89; 95% CI 1.10-3.24; p = 0.021). The analysis of the 24 patients who had biomarker determinations both in primary tumors and metastasis showed a better OS when AR/ER ratio in the metastasis was ≥ 0.90 (p = 0.022). Patients with a high AR/ER ratio in primary tumor that remained high in the metastasis had better prognosis in terms of OS (p = 0.011). Despite we suggested that the ratios AR/ER and AR/PgR could be used to identify patients with different prognosis, their real value needs to be better clarified in different BC settings through prospective studies.

Androgen receptor in advanced breast cancer: is it useful to predict the efficacy of anti-estrogen therapy?

Background

Androgen receptor (AR) is widely expressed in breast cancer (BC) but its role in estrogen receptor (ER)-positive tumors is still controversial. The AR/ER ratio has been reported to impact prognosis and response to antiestrogen endocrine therapy (ET).

Methods

We assessed whether AR in primary tumors and/or matched metastases is a predictor of efficacy of first-line ET in advanced BC. Patients who had received first-line ET (2002–2011) were recruited, while those given concomitant chemotherapy or trastuzumab or pretreated with > 2 lines of chemotherapy were excluded. ER, progesterone receptor (PgR), Ki67 and AR expression were assessed by immunohistochemistry, and HER2 mainly by fluorescent in-situ hybridization. Cut-offs of 1 and 10% immunostained cells were used to categorize AR expression.

Results

Among 102 evaluable patients, biomarkers were assessed in primary tumors in 70 cases and in metastases in 49, with 17 patients having both determinations. The overall concordance rate between primary tumors and metastases was 64.7% (95% CI 42%-87.4%) for AR status. AR status did not affect TTP significantly, whereas PgR and Ki67 status did. AR/PgR ≥0.96 was associated with a significantly shorter TTP (HR = 1.65, 95% CI 1.05-2.61, p = 0.028). AR status in primary tumors or metastases was not associated with progressive disease (PD) as best response. In contrast, Ki67 ≥ 20% and PgR < 10% showed a statistically significant association with PD as best response.

Conclusions

AR expression does not appear to be useful to predict the efficacy of ET in advanced BC, whereas Ki67 and PgR exert a greater impact on its efficacy.

Luminal A Breast Cancer and Molecular Assays: A Review

PURPOSE

Chemotherapy has been the historical mainstay of treatment for patients with breast cancer, with immunohistochemical markers and tumor characteristics driving treatment decisions. The discovery of different intrinsic subtypes of breast cancer has advanced the understanding of breast cancer, with gene-based assays shedding further light on tumor behavior and response to treatment.

DESIGN

This review focuses on the landscape of the luminal A subtype, its definition based on immunohistochemistry (IHC) and gene assays, the prognostic and predictive value of these assays, guideline recommendations, and treatment implications.

RESULTS

Clinical studies of the prognostic value of gene-based and IHC-based assays in patients with luminal A-subtype breast cancers suggest a better prognosis for these patients compared with those with breast cancers of other subtypes.

CONCLUSION

In today's era of precision medicine, the best treatment regimen for patients with luminal A-subtype tumors is still undetermined, but available data raise the question whether chemotherapy can be omitted and endocrine therapy alone is sufficient for this patient population.

IMPLICATIONS FOR PRACTICE

Immunohistochemical markers have traditionally guided treatment decisions in breast cancer. However, advances in gene-expression profiling and availability of gene-based assays have launched these newer tests into everyday clinical practice. Luminal A-subtype tumors are a unique subset that may have favorable tumor biology. Properly defining this tumor subtype is important and may identify a subset of patients for whom endocrine therapy alone is sufficient.

Discordance of the estrogen receptor and HER-2/neu in breast cancer from primary lesion to first and second metastatic site

BACKGROUND

Hormone receptor and HER-2/neu discordance between the primary lesion and first metastasis has been reported. This study was performed to determine further biomarker discordance rates between the first and subsequent metastatic breast cancer lesions.

METHODS

We performed a retrospective review of paired biomarkers from primary breast cancers compared to first reported and subsequent metastases from 103 patients with breast cancer. The estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu status were reported at all three time points. In addition, hormone, cytotoxic, and targeted treatments were recorded for primary and metastatic disease, and survival was determined.

RESULTS

Between the primary and first metastases, discordance rates for ER, PR, and HER-2/neu were 15.8%, 33.7%, and 14.3%, respectively. There was discordance between the first and second metastases for the ER receptor in 18.8%, PR receptor in 19.8%, and HER-2/neu in 10.7%. Overall, there was discordance between the primary tumor and either the first or second metastases for ER in 27.7%, PR receptor in 40.7%, and HER-2/neu in 19.6% of cases. Discordance of either ER or PR affected survival, with worse survival experienced by those patients with all three hormone receptors remaining negative, and intermediate survival reported for those with discordant tumors (ER χ2=14.27, p=0.0008; PR χ2=11.31, p=0.0035). There was no difference in survival for patients whose HER-2/neu tumors were discordant.

CONCLUSION

This study demonstrated that continued metastatic disease evolution may be associated with different tumor biology and that studies of metastatic lesions appear warranted, especially if targeted therapy is an option.

Evaluation of Tumor Cell Proliferation by Ki-67 Expression and Mitotic Count in Lymph Node Metastases from Breast Cancer

Few studies have addressed the risk of recurrence by assessing proliferation markers in lymph node metastasis from breast cancer. Here, we aimed to examine Ki-67 expression and mitotic count in lymph nodes in comparison with primary tumors. A cohort of node positive breast cancer (n = 168) was studied as a part of the prospective Norwegian Breast Cancer Screening Program (1996-2009). The percentage of Ki-67 positivity was counted per 500 tumor cells in hot-spot areas (x630). Mitotic count was conducted in the most cellular and mitotic active areas in 10 high power fields (x400). Our results showed that Ki-67 and mitotic count were significantly correlated between primary tumor and lymph nodes (Spearman`s correlation 0. 56 and 0.46, respectively) and were associated with most of the histologic features of the primary tumor. Univariate survival analysis (log-rank test) showed that high Ki-67 and mitotic count in the primary tumor and lymph node metastasis significantly predicted risk of recurrence. In multivariate analysis, mitotic count in the lymph node metastasis was an independent predictor of tumor recurrence. In conclusion, proliferation markers in lymph node metastases significantly predicted disease free survival in node positive breast cancer.