Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2-negative breast cancer

Accessible model predicts response in hormone receptor positive HER2 negative breast cancer receiving neoadjuvant chemotherapy

Hormone receptor-positive/HER2-negative breast cancer (BC) is the most common subtype of BC and typically occurs as an early, operable disease. In patients receiving neoadjuvant chemotherapy (NACT), pathological complete response (pCR) is rare and multiple efforts have been made to predict disease recurrence. We developed a framework to predict pCR using clinicopathological characteristics widely available at diagnosis. The machine learning (ML) models were trained to predict pCR (n = 463), evaluated in an internal validation cohort (n = 109) and validated in an external validation cohort (n = 151). The best model was an Elastic Net, which achieved an area under the curve (AUC) of respectively 0.86 and 0.81. Our results highlight how simpler models using few input variables can be as valuable as more complex ML architectures. Our model is freely available and can be used to enhance the stratification of BC patients receiving NACT, providing a framework for the development of risk-adapted clinical trials.

TROPION-Breast04: a randomized phase III study of neoadjuvant datopotamab deruxtecan (Dato-DXd) plus durvalumab followed by adjuvant durvalumab versus standard of care in patients with treatment-naïve early-stage triple negative or HR-low/HER2- breast cancer

Background

Despite treatment advances for patients with early-stage triple-negative breast cancer (TNBC) and hormone receptor (HR)-low/human epidermal growth factor receptor 2-negative (HER2-) breast cancer, treatments that improve clinical outcomes while mitigating toxicity are needed. Datopotamab deruxtecan (Dato-DXd), a TROP2-directed antibody-drug conjugate consisting of a humanized IgG1 monoclonal antibody attached via a plasma-stable cleavable linker to a topoisomerase-I inhibitor payload, has shown efficacy alone or in combination with durvalumab, a selective, high-affinity anti-programmed cell death ligand 1 antibody, in early-phase clinical studies.

Objectives

The primary objective of TROPION-Breast04 is to evaluate the efficacy and safety of neoadjuvant Dato-DXd plus durvalumab followed by adjuvant durvalumab with or without chemotherapy versus standard of care in patients with previously untreated early-stage TNBC or HR-low/HER2- breast cancer.

Design

This is an ongoing, international, phase III, open-label, randomized controlled study.

Methods and analysis

Approximately 1728 patients (aged ⩾18 years) will be randomized 1:1 to eight cycles of neoadjuvant Dato-DXd (6 mg/kg intravenously (IV) every 3 weeks (Q3W)) plus durvalumab (1120 mg IV Q3W) followed by nine cycles of adjuvant durvalumab (1120 mg IV Q3W) with or without chemotherapy versus eight cycles of pembrolizumab (200 mg IV Q3W) plus chemotherapy followed by nine cycles of adjuvant pembrolizumab (200 mg IV Q3W) with or without chemotherapy. Dual primary endpoints are pathological complete response by blinded central review and event-free survival by investigator assessment. Secondary endpoints include overall survival (key), distant disease-free survival, patient-reported outcomes, and safety.

Ethics

The study is approved by independent ethics committees and/or institutional review boards at each study site. All patients will provide written informed consent.

Discussion

This study will evaluate the potential use of neoadjuvant Dato-DXd plus durvalumab followed by adjuvant durvalumab with or without chemotherapy versus standard of care in patients with previously untreated early-stage TNBC or HR-low/HER2- breast cancer. The findings of this trial could lead to promising treatment options for these patients.

Trial registration

ClinicalTrials.gov identifier: NCT06112379.

Pembrolizumab and chemotherapy in high-risk, early-stage, ER+/HER2- breast cancer: a randomized phase 3 trial

Addition of pembrolizumab to neoadjuvant chemotherapy followed by adjuvant pembrolizumab improved outcomes in patients with high-risk, early-stage, triple-negative breast cancer. However, whether the addition of neoadjuvant pembrolizumab to chemotherapy would improve outcomes in high-risk, early-stage, estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer remains unclear. We conducted a double-blind, placebo-controlled phase 3 study (KEYNOTE-756) in which patients with previously untreated ER+/HER2- grade 3 high-risk invasive breast cancer (T1c-2 (≥2 cm), cN1-2 or T3-4, cN0-2) were randomly assigned (1:1) to neoadjuvant pembrolizumab 200 mg or placebo Q3W given with paclitaxel QW for 12 weeks, followed by four cycles of doxorubicin or epirubicin plus cyclophosphamide Q2W or Q3W. After surgery (with/without adjuvant radiation therapy), patients received adjuvant pembrolizumab or placebo for nine cycles plus adjuvant endocrine therapy. Dual primary endpoints were pathological complete response and event-free survival in the intention-to-treat population. In total, 635 patients were assigned to the pembrolizumab-chemotherapy arm and 643 to the placebo-chemotherapy arm. At the study's prespecified first interim analysis, the pathological complete response rate was 24.3% (95% confidence interval (CI), 21.0-27.8%) in the pembrolizumab-chemotherapy arm and 15.6% (95% CI, 12.8-18.6%) in the placebo-chemotherapy arm (estimated treatment difference, 8.5 percentage points; 95% CI, 4.2-12.8; P = 0.00005). Event-free survival was not mature in this analysis. During the neoadjuvant phase, treatment-related adverse events of grade ≥3 were reported in 52.5% and 46.4% of patients in the pembrolizumab-chemotherapy and placebo-chemotherapy arms, respectively. In summary, the addition of pembrolizumab to neoadjuvant chemotherapy significantly improved the pathological complete response rate in patients with high-risk, early-stage ER+/HER2- breast cancer. Safety was consistent with the known profiles of each study treatment. Follow-up continues for event-free survival. ClinicalTrials.gov identifier: NCT03725059 .

Subtype-specific prognostic impact of Bcl-2 in HER2-positive and HER2-negative breast cancer

Bcl-2, a key regulator of cellular apoptosis, is typically linked to adverse prognosis in solid tumors due to its inhibition of apoptotic cell death and promotion of cellular proliferation, leading to tumor progression. However, studies on Bcl-2 in breast cancer have shown inconsistent results, with some indicating favorable outcomes. This study aims to determine the subtype-specific role of Bcl-2 in breast cancer. Female breast cancer patients who completed primary treatment at Wonju Severance Hospital, Korea, from 2004 to 2018 were included. Clinicopathological characteristics, including Bcl-2 expression, were collected, and patients were classified based on Bcl-2 expression in more than or less than 10% of tumor cells. Kaplan-Meier curves compared recurrence-free interval (RFI) and overall survival (OS). The final cohort of 617 patients, with a mean age of 54.79 ± 11.2 years, showed no overall survival difference by Bcl-2 status (p = 0.616). In HER2-overexpressed patients, high Bcl-2 expression was linked to poor prognosis (p = 0.0021). This trend appeared in ER-positive (p = 0.297) and ER-negative (p = 0.029) subgroups. Conversely, in HER2-negative patients, Bcl-2 overexpression indicated better survival (p = 0.009), consistent in ER-positive (p = 0.259) and ER-negative (p = 0.010) subgroups. Bcl-2's impact on survival varies with HER2 status, showing poor prognosis in HER2-overexpressed and better prognosis in HER2-negative patients.

Breast Cancers With Intermediate Estrogen Receptor Expression: Characteristics, Prognosis and Treatment

In the era of personalized oncology biomarkers that identify subgroups of specific cancers and help predict response to specific therapies are critical tools for prognosis determination and therapeutic decisions. The Estrogen Receptor (ER) had been one of the first biomarkers used in breast cancer and has helped advance the field of breast oncology by contributing to the success of hormonal therapies for the ER positive subgroup of the disease. Expression of the receptor in 1% or more of tumor cells in immunohistochemical sections define currently the ER positive subgroup of breast cancers, which may be treated with regimens that include hormonal inhibitors. The highest sensitivity and benefit of hormonal therapies is observed in cancers with robust ER expression (in 90% to 100% of tumor cells). However, it has become clear that the subgroup of breast cancers with low ER expression (in 1% to 10% of tumor cells) behaves similarly to ER negative breast cancers and has an inferior response to hormonal therapies. The behavior of the rest of ER positive breast cancers with an intermediate ER expression between these 2 extremes (ER expression between 10% and 90%) is less well described and their response to estrogen targeting therapies is less clear. Breast cancers with intermediate ER expression represent a small subgroup of ER positive breast cancers and the wide range of expressions suggests heterogeneity. This review will discuss this subgroup of ER positive breast cancers and examine their genomic landscape and therapeutic repercussions.

Immune and gene-expression profiling in estrogen receptor low and negative early breast cancer

BACKGROUND

The cutoff of <1% positive cells to define estrogen receptor (ER) negativity by immunohistochemistry (IHC) in breast cancer (BC) is debated. We explored the tumor immune microenvironment and gene-expression profile of patients with early-stage HER2-negative ER-low (ER 1%-9%) BC, comparing them to ER-negative (ER <1%) and ER-intermediate (ER 10%-50%) tumors.

METHODS

Among 921 patients with early-stage I-III, ER ≤50%, HER2-negative BCs, tumors were classified as ER-negative (n = 712), ER-low (n = 128), or ER-intermediate (n = 81). Tumor-infiltrating lymphocytes (TILs) were evaluated. CD8+, FOXP3+ cells, and PD-L1 status were assessed by IHC and quantified by digital pathology. We analyzed 776 BC-related genes in 116 samples. All tests were 2-sided at a <.05 significance level.

RESULTS

ER-low and ER-negative tumors exhibited similar median TILs, statistically significantly higher than ER-intermediate tumors. CD8/FOXP3 ratio and PD-L1 positivity rates were comparable between ER-low and ER-negative groups. These groups showed similar enrichment in basal-like intrinsic subtypes and comparable expression of immune-related genes. ER-low and ER-intermediate tumors showed significant transcriptomic differences. High TILs (≥30%) were associated with improved relapse-free survival (RFS) in ER-low (5-year RFS 78.6% vs 66.2%, log-rank P = .033, hazard ratio [HR] 0.37 [95% CI = 0.15 to 0.96]) and ER-negative patients (5-year RFS 85.2% vs 69.8%, log-rank P < .001, HR 0.41 [95% CI = 0.27 to 0.60]).

CONCLUSIONS

ER-low and ER-negative tumors are similar biological and molecular entities, supporting their comparable clinical outcomes and treatment responses, including to immunotherapy. Our findings contribute to the growing evidence calling for a reevaluation of ER-positive BC classification and management, aligning ER-low and ER-negative tumors more closely.

Contrast-enhanced mammography for surveillance in women with a personal history of breast cancer

PURPOSE

Women with a personal history of breast cancer have an increased risk of subsequent breast malignancy and may benefit from more sensitive surveillance than conventional mammography (MG). We previously reported outcomes for first surveillance episode using contrast-enhanced mammography (CEM), demonstrating higher sensitivity and comparable specificity to MG. We now report CEM performance for subsequent surveillance.

METHODS

A retrospective study of 1,190 women in an Australian hospital setting undergoing annual surveillance following initial surveillance CEM between June 2016 and December 2022. Outcome measures were recall rate, cancer detection rate, contribution of contrast to recalls, false positive rate, interval cancer rate and characteristics of surveillance detected and interval cancers.

RESULTS

2,592 incident surveillance episodes were analysed, of which 93% involved contrast-based imaging. Of 116 (4.5%) recall episodes, 40/116 (34%) recalls were malignant (27 invasive; 13 ductal carcinoma in situ), totalling 15.4 cancers per 1000 surveillance episodes. 55/116 (47%) recalls were contrast-directed including 17/40 (43%) true positive recalls. Tumour features were similar for contrast-directed recalls and other diagnoses. 8/9 (89%) of contrast-directed invasive recalls were Grade 2-3, and 5/9 (56%) were triple negative breast cancers. There were two symptomatic interval cancers (0.8 per 1000 surveillance episodes, program sensitivity 96%).

CONCLUSION

Routine use of CEM in surveillance of women with PHBC led to an increase in the detection of clinically significant malignant lesions, with a low interval cancer rate compared to previous published series. Compared to mammographic surveillance, contrast-enhanced mammography increases the sensitivity of surveillance programs for women with PHBC.

Comparison of neoadjuvant chemotherapy response and prognosis among pegylated liposomal doxorubicin, epirubicin and pirarubicin in HR ⩽ 10%/HER2-negative breast cancer: an exploratory real-world multicentre cohort study

Background

Pegylated liposomal doxorubicin (PLD), epirubicin and pirarubicin are the main anthracyclines widely used in China. PLD demonstrates therapeutic response comparable to epirubicin and pirarubicin in neoadjuvant chemotherapy (NAC) of breast cancer.

Objectives

The objectives of our study were to retrospectively assess the real-world effectiveness and prognostic characteristics of PLD as NAC for HR ⩽ 10%/human epidermal growth factor receptor 2 (HER2)-negative breast cancer.

Design

This was a retrospective study.

Methods

Our study enrolled patients with HR ⩽ 10%/HER2-negative breast cancer who received PLD-, epirubicin- or pirarubicin-based NAC from three centres in Hunan Province, China, between 2015 and 2022. We employed inverse probability of treatment weighting to balance the differences in patients' characteristics among the PLD, epirubicin, and pirarubicin groups. The endpoints were pathological complete response (pCR), event-free survival (EFS), and overall survival (OS).

Results

A total of 267 patients were included. After NAC, the pCR rates in PLD group were superior to epirubicin group (PLD, 34.1%; epirubicin, 20.8%, p = 0.038). The differences in EFS (log-rank p = 0.99) and OS (log-rank p = 0.33) among the three groups were not statistically significant. Among the three groups, non-pCR patients had worse EFS than pCR patients (log-rank p = 0.014). For patients with pCR, the differences in EFS (log-rank p = 0.47) and OS (log-rank p = 0.38) were not statistically significant among the three groups, and the EFS (log-rank p = 0.59) and OS (log-rank p = 0.14) of non-pCR patients in the PLD group were similar to those in the epirubicin and pirarubicin groups.

Conclusion

PLD had a similar therapeutic response and prognosis compared to epirubicin or pirarubicin in NAC for patients with HR ⩽ 10%/HER2 negative breast cancer, which means that PLD represents a potential NAC option.

Prediction of response to neoadjuvant chemotherapy by MammaTyper® across breast cancer subtypes: A retrospective cross-sectional study

BACKGROUND

Neoadjuvant chemotherapy (NACT) is widely used in the treatment of triple-negative and HER2-positive breast cancer (BC), but its use in estrogen receptor (ER) and/or progesterone receptor (PR) positive/HER2-negative BC is questioned because of the low pathologic complete response (pCR) rates. This retrospective study assessed the mRNA-based MammaTyper® assay's capability of predicting pCR with NACT, and ER, PR, Ki67, and HER2 status at immunohistochemical (IHC) through transcriptomics.

METHODS

Diagnostic biopsies from 76 BC patients treated at the Cremona Hospital between 2012-2018 were analyzed. Relative mRNA expression levels of ERBB2, ESR1, PGR, and MKI67 were measured using the MammaTyper® kit and integrated into a pCR score. Predicting capability of pCR and standard IHC biomarkers could be assessed with ROC curves in 75 and 76 patients, respectively.

RESULTS

Overall, 68.0% patients obtained a MammaTyper® high-score and 32.0% a MammaTyper® low-score. Among high-score patients, 62.7% achieved pCR, compared to 16.7% in the low-score group (p = 0.0003). The binary MammaTyper® score showed good prediction of pCR in the overall cohort (area under curve [AUC] = 0.756) and in HR+/HER2-negative cases (AUC = 0.774). In cases with residual disease, the continuous MammaTyper® score correlated moderately with residual tumor size and decrease in tumor size. MammaTyper® showed substantial agreement with IHC for ESR1/ER and ERBB2/HER2, and moderate agreement for PGR/PR and MKI67/Ki67.

CONCLUSION

Overall, MammaTyper® pCR score may serve as a standardized tool for predicting NACT response in HR+/HER2-negative BC, potentially guiding treatment strategies. Additionally, it could provide a more standardized and reproducible assessment of ER, PR, HER2, and Ki67 status.

Adjuvant treatment in hormone receptor-positive early breast cancer: New approaches of endocrine therapy

Breast cancer is the most common cancer in women, and luminal breast cancer is the predominant subtype, characterized by the presence of estrogen receptors and/or progesterone receptors in tumor cells. Adjuvant endocrine therapy is the pivotal approach in the management of luminal early breast cancer. Hence, new therapeutic approaches have been studied during the last few years, especially in patients with high risk of recurrence.Here we provide a summary of the most recent clinical trials evaluating adjuvant treatment in hormone-receptors-positive early breast cancer. First, the main cornerstone is related to the role of extended endocrine treatment, which has been widely investigated to access a benefit in disease-free survival and overall survival (only the GIM4 trial has positive feedback about survival) and to tailor the treatment according to patient compliance. The results highlighted an advantage in extending the use of endocrine treatment for at least seven full years, considering aromatase inhibitors as principal drugs. Second, the shift of CDK4/6 inhibitors (CDK4/6i) from advanced to early setting reported positive outcomes, with favorable results from MonarchE and NATALEE trials, using Abemaciclib and Ribociclib respectively, even if non-negligible toxicities have been reported. Last, the use of PARP inhibitors for BRCA1/2 mutated patients has been evaluated in the OlympiA trial (Olaparib), observing a comparable benefit between hormone-receptors-positive and triple-negative early breast cancer.However, more data are still required to better select patients that could benefit more from CDK4/6i considering side effects too, and sequential treatments are still not codified.

Real-world overall survival and characteristics of patients with ER-zero and ER-low HER2-negative breast cancer treated as triple-negative breast cancer: a Swedish population-based cohort study

Background

Estrogen receptor-low (ER-low) HER2-negative breast cancer has similar pathological and molecular characteristics as triple-negative breast cancer (TNBC), and it is questionable whether it should be considered a separate entity. When the international guidelines lowered the cutoff for ER positivity to ≥1% in 2010, the ≥10% threshold was kept in Sweden. ER-low breast cancer (ER 1-9%) is thus in Sweden treated as TNBC. We aimed to describe patient and tumor characteristics, treatment patterns and overall survival in a Swedish population-based cohort of patients with ER-zero and ER-low HER2-negative breast cancer treated as TNBC.

Methods

All TNBC cases diagnosed in Sweden 2008-2020 were included in a population-based cohort study. Patient, tumor and treatment characteristics were analyzed by ER-status (ER 0% vs 1-9%), and associations between subgroups compared using χ2 test. Survival endpoint was overall survival (OS), and Kaplan-Meier curves were estimated. Cox proportional hazards models were used to estimate adjusted hazard ratios comparing ER-low to ER-zero.

Findings

Of the 5655 tumors, 90.1% had an ER expression of 0%, while 9.9% were ER-low. ER-low tumors were grade III in 69.4% (80.8% in ER-zero tumors, p-value = 0.001), with a median Ki67 of 60% (63% in ER-zero tumors, p-value = 0.005). There were no significant differences in given chemotherapy (p = 0.546). A pathological complete response (pCR) was achieved in 28.1% of ER-low tumors (25.1% in ER-zero tumors). In the unadjusted analysis of OS, women with ER-low disease had a borderline but not significantly better OS than those with ER-zero disease (HR 0.84 (95% CI 0.71-1.00), p = 0.052). ER-status 1-9% vs 0% was not associated with OS in the multivariable analysis (HR 1.11 (0.90-1.36)). Distant disease-free survival did not differ by ER-status 0% vs 1-9% (HR 0.97 for ER-zero vs ER-low (0.62-1.53), p = 0.905). After preoperative treatment, the impact of pCR for OS did not significantly differ between ER-zero or ER-low disease.

Interpretation

ER-low HER2-negative breast cancer has characteristics and prognosis similar to TNBC, when treated in the same way. Therefore, it seems reasonable to use a ≥10% threshold for ER positivity. This would provide patients with ER-low tumors the same treatment opportunities as patients with TNBC, within studies and within clinical routine.

Funding

This work was financially supported by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA, in accordance with terms and conditions of a Master Collaboration Agreement between the company and Karolinska Institutet.

Comparison of neoadjuvant chemotherapy response and prognosis between HR-low/HER2-negative BC and TNBC: an exploratory real-world multicentre cohort study

Objective

Hormone receptor (HR)-low/HER2-negative breast cancers (BCs) are more likely to be basal-like BCs, with similar molecular features and gene expression profiles to HR-negative (estrogen receptor <1% or negative and progesterone receptor <1% or negative) BCs. Recently, with the clinical application of adjuvant intensive therapy for triple-negative breast cancer (TNBC), the prognosis of TNBC patients without pathological complete response (pCR) has significantly improved. Therefore, it is necessary to reanalyse the prognostic characteristics of clinically high-risk HR-low/HER2-negative BC.

Methods

According to the inclusion and exclusion standards, 288 patients with HR-low/HER2-negative BC and TNBC who received NAC and were followed up between 2015 and 2022 at three breast centres in Hunan Province, China, were enrolled. Inverse probability of treatment weighting (IPTW) was utilized to mitigate imbalances in baseline characteristics between the HR-low/HER2-negative BC group and TNBC group regarding event-free survival (EFS) and overall survival (OS). The primary clinical endpoints were pCR and EFS, while the secondary endpoints included OS, objective response rate (ORR), and clinical benefit rate (CBR).

Results

The pCR rate (27.1% vs. 28.0%, P = 1.000), ORR rate (76.9% vs. 78.3%, P = 0.827) and CBR rate (89.7% vs. 96.5%, P = 0.113) after NAC were similar between the HR-low/HER2-negative BC and the TNBC group. EFS in patients with non-pCR from the 2 groups was significantly inferior in comparison to patients with pCR (P = 0.001), and the 3-year EFS was 94.74% (95% CI = 85.21% to 100.00%) and 57.39% (95% CI =43.81% to 75.19%) in patients with pCR and non-pCR from the HR-low/HER2-negative BC group, respectively, and 89.70% (95% CI = 82.20% to 97.90%) and 69.73% (95% CI = 62.51% to 77.77%) in the TNBC patients with pCR and non-pCR, respectively.

Conclusions

In the real world, the therapeutic effects of NAC for HR-low/HER2-negative BCs and TNBCs were similar. EFS of patients with non-pCR in the HR-low/HER2-negative BC group was inferior to that of the TNBC group with non-pCR, suggesting that it is necessary to explore new adjuvant intensive therapy strategies for these patients.

Omission of Breast Surgery in Predicted Pathologic Complete Response after Neoadjuvant Systemic Therapy: A Multicenter, Single-Arm, Non-inferiority Trial

PURPOSE

Advances in chemotherapeutic and targeted agents have increased pathologic complete response (pCR) rates after neoadjuvant systemic therapy (NST). Vacuum-assisted biopsy (VAB) has been suggested to accurately evaluate pCR. This study aims to confirm the non-inferiority of the 5-year disease-free survival of patients who omitted breast surgery when predicted to have a pCR based on breast magnetic resonance imaging (MRI) and VAB after NST, compared with patients with a pCR who had undergone breast surgery in previous studies.

METHODS

The Omission of breast surgery for PredicTed pCR patients wIth MRI and vacuum-assisted bIopsy in breaST cancer after neoadjuvant systemic therapy (OPTIMIST) trial is a prospective, multicenter, single-arm, non-inferiority study enrolling in 17 tertiary care hospitals in the Republic of Korea. Eligible patients must have a clip marker placed in the tumor and meet the MRI criteria suggesting complete clinical response (post-NST MRI size ≤ 1 cm and lesion-to-background signal enhancement ratio ≤ 1.6) after NST. Patients will undergo VAB, and breast surgery will be omitted for those with no residual tumor. Axillary surgery can also be omitted if the patient was clinically node-negative before and after NST and met the stringent criteria of MRI size ≤ 0.5 cm. Survival and efficacy outcomes are evaluated over five years.

DISCUSSION

This study seeks to establish evidence for the safe omission of breast surgery in exceptional responders to NST while minimizing patient burden. The trial will address concerns about potential undertreatment due to false-negative results and recurrence as well as improved patient-reported quality of life issues from the omission of surgery. Successful completion of this trial may reshape clinical practice for certain breast cancer subtypes and lead to a safe and less invasive approach for selected patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05505357. Registered on August 17, 2022. Clinical Research Information Service Identifier: KCT0007638. Registered on July 25, 2022.

Clinical and Biomarker Findings of Neoadjuvant Pembrolizumab and Carboplatin Plus Docetaxel in Triple-Negative Breast Cancer: NeoPACT Phase 2 Clinical Trial

Importance

Addition of pembrolizumab to anthracycline-based chemotherapy improves pathologic complete response (pCR) and event-free survival (EFS) in triple-negative breast cancer (TNBC). The efficacy of anthracycline-free chemoimmunotherapy in TNBC has not been assessed.

Objective

To assess the efficacy of the anthracycline-free neoadjuvant regimen of carboplatin and docetaxel plus pembrolizumab in TNBC.

Design, Setting, and Participants

This was an open-label phase 2 clinical trial including a single group of patients with stage I to III TNBC enrolled at 2 sites who received neoadjuvant carboplatin and docetaxel plus pembrolizumab every 21 days for 6 cycles. Participants were enrolled from 2018 to 2022.

Intervention or Exposure

Carboplatin (with an area under the free carboplatin plasma concentration vs time curve of 6) and docetaxel (75 mg/m2) plus pembrolizumab (200 mg) every 21 days for 6 cycles. Myeloid growth factor support was administered with all cycles.

Main Outcomes and Measures

Primary end point was pathologic complete response (pCR) defined as no evidence of invasive tumor in breast and axilla. The secondary end points were residual cancer burden, EFS, toxicity, and immune biomarkers. RNA isolated from pretreatment tumor tissue was subjected to next-generation sequencing. Specimens were classified as positive or negative for the 44-gene DNA damage immune response (DDIR) signature and for the 27-gene tumor immune microenvironment (TIM; DetermaIO) signature using predefined cutoffs. Stromal tumor-infiltrating lymphocytes (sTILs) were evaluated using standard criteria. Programmed cell death-ligand 1 (PD-L1) testing was performed using a standard immunohistochemical assay.

Results

Among the eligible study population of 115 female patients (median [range] age, 50 [27-70] years) who enrolled from September 2018 to January 2022, 39% had node-positive disease. pCR and residual cancer burden 0 + 1 rates were 58% (95% CI, 48%-67%) and 69% (95% CI, 60%-78%), respectively. Grade 3 or higher immune-mediated adverse events were observed in 3.5% of patients. sTILs, PD-L1, DDIR, and TIM were each predictive of pCR in multivariable analyses. The areas under curve for pCR were 0.719, 0.740, 0.699, and 0.715 for sTILs, PD-L1, DDIR, and TIM, respectively. Estimated 3-year EFS was 86% in all patients; 98% in pCR group and 68% in no-pCR group.

Conclusions and Relevance

The findings of the phase 2 clinical trial indicate that neoadjuvant carboplatin and docetaxel plus pembrolizumab shows encouraging pCR and 3-year EFS. The regimen was well tolerated, and immune enrichment as identified by various biomarkers was independently predictive of pCR. These results provide data on an alternative anthracycline-free chemoimmunotherapy regimen for patients who are not eligible for anthracycline-based regimens and support further evaluation of this regimen as a chemotherapy de-escalation strategy in randomized studies for TNBC.

Trial Registration

ClinicalTrials.gov Identifier: NCT03639948.

Comprehensive and Accurate Molecular Profiling of Breast Cancer through mRNA Expression of ESR1, PGR, ERBB2, MKI67, and a Novel Proliferation Signature

BACKGROUND

An accurate status determination of breast cancer biomarkers (ER, PR, HER2, Ki67) is crucial for guiding patient management. The "gold standard" for assessing these biomarkers in FFPE tissue is IHC, which faces challenges in standardization and exhibits substantial variability. In this study, we compare the concordance of a new commercial RT-qPCR kit with IHC in determining BC biomarker status.

METHODS

The performance was evaluated using 634 FFPE specimens, which underwent histological analysis in accordance with standard of care methods. HER2 2+ tumors were referred to ISH testing. An immunoreactive score of ≥2/12 was considered positive for ER/PR and 20% staining was used as a cut-off for Ki67 high/low score. RT-qPCR and results calling were performed according to the manufacturer's instructions.

RESULTS

High concordance with IHC was seen for all markers (93.2% for ER, 87.1% for PR, 93.9% for HER2, 77.9% for Ki67 and 80.1% for proliferative signature (assessed against Ki67 IHC)).

CONCLUSIONS

By assessing the concordance with the results obtained through IHC, we sought to demonstrate the reliability and utility of the kit for precise BC subtyping. Our findings suggest that the kit provides a highly precise and accurate quantitative assessment of BC biomarkers.

The Clinical and Pathological Characteristics That Differentiate Cases With "Low Estrogen Receptor Expression" From Triple-Negative Breast Cancer

Objective

Estrogen receptor (ER) expression is an immunohistochemical marker that is examined in all invasive breast cancers and has prognostic and predictive value. ER-positive breast cancers refer to those that show positivity for ER at 1% cellular expression or higher. The American Society of Clinical Oncology/College of American Pathologists guidelines suggest using the term "low ER-positive breast cancer" for tumors with ER expression between 1% and 10%. Low ER-positive breast cancers exhibit similarities, in terms of disease-free survival and overall survival rates, to triple-negative breast cancers (TNBCs) rather than ER-positive breast cancers. In this study, our aim was to compare the clinicopathological characteristics of low ER-positive breast cancer cases diagnosed and followed in our clinic with TNBCs.

Materials and Methods

A total of 26 cases of low ER-positive breast cancer diagnosed at University of Health Sciences Turkey, İzmir Tepecik Training and Research Hospital between 2010 and 2016 were retrieved from hospital records. The relevant histopathology slides and blocks were retrieved and re-evaluated retrospectively through microscopic examination. Thirteen cases that met the criteria were included in the study. Additionally, a consecutive series of 13 TNBC cases that did not receive neoadjuvant treatment within the same time period were identified.

Results

In the low ER-positive group, the presence of tumor necrosis, as well as histological grade, nuclear grade and Ki-67 proliferation index were significantly lower compared to the TNBC group. Ductal carcinoma in situ (DCIS) was significantly more common in the low ER-positive group compared to the TNBC group. There were no significant differences between the two groups in terms of tumor size, histological tumor type, axillary lymph node involvement, tumor margins, peritumoral and intratumoral inflammation, local recurrence, distant metastasis, survival, and other characteristics.

Conclusion

Although our study consisted of a small number of cases, some features showed significant differences between low ER-positive breast cancers and TNBCs. Histological and nuclear grades, as well as the presence of a DCIS component, were associated with low ER-positive breast cancer. In contrast, the presence of tumor necrosis, as well as Grade 3 features and a high Ki-67 proliferation index indicated TNBC.

Updates in the Use of Immunohistochemical Stains in Breast and Gynecologic Pathology

CONTEXT.—

The use of immunohistochemical stains in breast and gynecologic pathology has become increasingly complex, with various diagnostic, prognostic, and predictive applications.

OBJECTIVE.—

To provide an update and review of immunohistochemical stains used in the practice of breast and gynecologic pathology. Established and new entities are reviewed, with descriptions of histomorphology and immunohistochemical staining patterns and discussion of interpretive pitfalls.

DATA SOURCES.—

Data were obtained from review of the English-language literature and firsthand experience of the authors in breast and gynecologic pathology.

CONCLUSIONS.—

Many entities in breast and gynecologic pathology benefit from evaluation with various immunohistochemical stains. These studies not only aid in the diagnosis and staging of tumors but also can provide prognostic and predictive information. Updated guidelines for recommended ancillary studies such as mismatch repair, p53, and human epidermal growth factor receptor 2 (HER2) studies in endometrium, as well as estrogen and progesterone receptors and HER2 in breast, are discussed. Finally, the use and interpretation of established and novel immunohistochemical stains are discussed in various breast and gynecologic malignancies.

Exploring the interaction between extracellular matrix components in a 3D organoid disease model to replicate the pathophysiology of breast cancer

In vitro models are necessary to study the pathophysiology of the disease and the development of effective, tailored treatment methods owing to the complexity and heterogeneity of breast cancer and the large population affected by it. The cellular connections and tumor microenvironments observed in vivo are often not recapitulated in conventional two-dimensional (2D) cell cultures. Therefore, developing 3D in vitro models that mimic the complex architecture and physiological circumstances of breast tumors is crucial for advancing our understanding of the illness. A 3D scaffold-free in vitro disease model mimics breast cancer pathophysiology by allowing cells to self-assemble/pattern into 3D structures, in contrast with other 3D models that rely on artificial scaffolds. It is possible that this model, whether applied to breast tumors using patient-derived primary cells (fibroblasts, endothelial cells, and cancer cells), can accurately replicate the observed heterogeneity. The complicated interactions between different cell types are modelled by integrating critical components of the tumor microenvironment, such as the extracellular matrix, vascular endothelial cells, and tumor growth factors. Tissue interactions, immune cell infiltration, and the effects of the milieu on drug resistance can be studied using this scaffold-free 3D model. The scaffold-free 3D in vitro disease model for mimicking tumor pathophysiology in breast cancer is a useful tool for studying the molecular basis of the disease, identifying new therapeutic targets, and evaluating treatment modalities. It provides a more physiologically appropriate high-throughput platform for screening large compound library in a 96-384 well format. We critically discussed the rapid development of personalized treatment strategies and accelerated drug screening platforms to close the gap between traditional 2D cell culture and in vivo investigations.

Estrogen-Receptor-Low-Positive Breast Cancer: Pathological and Clinical Perspectives

The expression of estrogen receptors (ERs) in breast cancer (BC) represents a strong prognostic and predictive biomarker and directs therapeutic decisions in early and advanced stages. ER-low-positive BC, defined by the immunohistochemical (IHC) expression of ERs from 1% to 9%, constitutes a distinct subset of total BC cases. Guidelines recommend that a low expression of ERs be reported in pathology reports since the benefit of endocrine therapy in patients with ER-low-positive BC is uncertain. Recently, several cohorts, mostly of a retrospective nature, have been published, reporting the clinicopathological characteristics and outcomes of ER-low-positive BC. However, the majority of the data focus on early-stage BC and the use of (neo)adjuvant therapy, and there is a significant lack of data regarding metastatic ER-low-positive BC. Further factors, including tumor heterogeneity as well as the potential loss of ER expression due to endocrine resistance, should be considered. Including patients with ER-low-positive BC in clinical trials for triple-negative breast cancer (TNBC) might improve the understanding of this entity and allow novel therapeutic approaches. The design and conduction of randomized clinical trials regarding this subgroup of patients are greatly anticipated.

Antibody-drug conjugates in HER-2 negative breast cancers with poor prognosis

Antibody drug conjugates (ADCs) comprise a rapidly growing class of targeted drugs that selectively deliver a cytotoxic agent to cancer cells, reducing the side effects associated with conventional chemotherapy. Breast cancer (BC) is a heterogeneous entity. The need for effective therapies for HER-2 negative BCs with poor prognosis, such as triple-negative or endocrine-resistant BC, remains unmet due to the lack of potential targets for treatments. These BC subtypes are not candidates for hormonal or anti-HER-2 agents. However, ongoing clinical trials exploring the use of ADCs with a wide range of targets have shown potential for this treatment modality. In this review, we present the current state of knowledge regarding the role of ADC and speculate on novel approaches including ADC combination therapies, new molecular targets, and the role of other subclasses of ADCs (bicycle drug conjugates, bispecific ADCs, immune modulating ADCs) in this clinical scenario.

Neoadjuvant camrelizumab plus nab-paclitaxel and epirubicin in early triple-negative breast cancer: a single-arm phase II trial

Immunotherapy combined with chemotherapy has been demonstrated to be effective in early triple-negative breast cancer (TNBC). In this single-arm, phase II study with Simon's two-stage design, we investigated the efficacy and safety of neoadjuvant camrelizumab plus chemotherapy in patients with early TNBC (NCT04213898). Eligible female patients aged 18 years or older with histologically confirmed treatment-naïve early TNBC were treated with camrelizumab (200 mg, on day 1), nab-paclitaxel (125 mg/m2, on days 1, 8, and 15), and epirubicin (75 mg/m2, on day 1) every three weeks for six cycles. The primary end point was the pathological complete response; secondary endpoints included safety, objective response rate, and long-term survival outcomes of event-free survival, disease-free survival, and distant disease-free survival. A total of 39 patients were enrolled between January 2020 and October 2021. Twenty-five patients achieved a pathological complete response (64.1%, 95%CI: 47.2, 78.8). The objective response rate was 89.7% (95%CI: 74.8, 96.7), including 35 patients with partial responses. Treatment-related adverse events of grade 3 or 4 occurred in 30 (76.9%) patients. In conclusion, the trial meets the prespecified endpoints showing promising efficacy and manageable safety of neoadjuvant camrelizumab plus nab-paclitaxel and epirubicin chemotherapy in female patients with early TNBC. Long-term survival outcomes are still pending.

Updates on Triple-Negative Breast Cancer in Type 2 Diabetes Mellitus Patients: From Risk Factors to Diagnosis, Biomarkers and Therapy

Triple-negative breast cancer (TNBC) is usually the most malignant and aggressive mammary epithelial tumor characterized by the lack of expression for estrogen receptors and progesterone receptors, and the absence of epidermal growth factor receptor (HER)2 amplification. Corresponding to 15-20% of all breast cancers and well-known by its poor clinical outcome, this negative receptor expression deprives TNBC from targeted therapy and makes its management therapeutically challenging. Type 2 diabetes mellitus (T2DM) is the most common ageing metabolic disorder due to insulin deficiency or resistance resulting in hyperglycemia, hyperinsulinemia, and hyperlipidemia. Due to metabolic and hormonal imbalances, there are many interplays between both chronic disorders leading to increased risk of breast cancer, especially TNBC, diagnosed in T2DM patients. The purpose of this review is to provide up-to-date information related to epidemiology and clinicopathological features, risk factors, diagnosis, biomarkers, and current therapy/clinical trials for TNBC patients with T2DM compared to non-diabetic counterparts. Thus, in-depth investigation of the diabetic complications on TNBC onset, development, and progression and the discovery of biomarkers would improve TNBC management through early diagnosis, tailoring therapy for a better outcome of T2DM patients diagnosed with TNBC.

Radiomic Features Applied to Contrast Enhancement Spectral Mammography: Possibility to Predict Breast Cancer Molecular Subtypes in a Non-Invasive Manner

We aimed to investigate the association between the radiomic features of contrast-enhanced spectral mammography (CESM) images and a specific receptor pattern of breast neoplasms. In this single-center retrospective study, we selected patients with neoplastic breast lesions who underwent CESM before a biopsy and surgical assessment between January 2013 and February 2022. Radiomic analysis was performed on regions of interest selected from recombined CESM images. The association between the features and each evaluated endpoint (ER, PR, Ki-67, HER2+, triple negative, G2-G3 expressions) was investigated through univariate logistic regression. Among the significant and highly correlated radiomic features, we selected only the one most associated with the endpoint. From a group of 321 patients, we enrolled 205 malignant breast lesions. The median age at the exam was 50 years (interquartile range (IQR) 45-58). NGLDM_Contrast was the only feature that was positively associated with both ER and PR expression (p-values = 0.01). NGLDM_Coarseness was negatively associated with Ki-67 expression (p-value = 0.02). Five features SHAPE Volume(mL), SHAPE_Volume(vx), GLRLM_RLNU, NGLDM_Busyness and GLZLM_GLNU were all positively and significantly associated with HER2+; however, all of them were highly correlated. Radiomic features of CESM images could be helpful to predict particular molecular subtypes before a biopsy.

Clinical implication of low estrogen receptor (ER-low) expression in breast cancer

Breast cancer is a heterogeneous disease, and the estrogen receptor (ER) remains the most important biomarker in breast oncology. Most guidelines set a positive expression threshold of 1% staining in immunohistochemistry (IHC) to define ER positivity. However, different expression levels may be associated with diverse degrees of sensitivity to endocrine therapy as ER expression may impact breast cancer molecular biology as a continuous variable. ER-lo tumors, defined as those with 1-10% ER expression, represent a relatively small subgroup of breast cancer patients, with an estimated prevalence of 2-7%. These tumors are similar to ERneg disease in their molecular landscape, clinicopathological characteristics, prognosis, and response to therapy. Nevertheless, a proportion may retain some degree of ER signaling dependency, and the possibility of responding to some degree to endocrine therapy cannot be completely ruled out. This review article discusses the most important considerations regarding the definition of ER positivity, pathology assessment, prognosis, and therapeutic implication of ERlo breast cancer from the medical oncology perspective.

Intrinsic subtypes and therapeutic decision-making in hormone receptor-positive/HER2-negative metastatic breast cancer with visceral crisis: A case report

Background

CDK4/6 inhibitors (CDKi), namely, palbociclib, ribociclib, and abemaciclib, combined with either an aromatase inhibitor (AI) or fulvestrant are the standard first/second line for hormone receptor-positive(HR+)/HER2-negative(neg) metastatic breast cancer (MBC). However, the choice of one specific CDKi is arbitrary and based on the physician's experience with the drug, toxicity profile, and patient's preferences, whereas biomarkers for optimal patient selection have not been established so far. Moreover, upfront chemotherapy is still recommended in case of clinical presentation with visceral crisis, despite no evidence of superior benefit for chemotherapy regimens against CDKi-based regimens. Recent correlative biomarker analyses from pivotal trials of palbociclib and ribociclib showed that HR+/HER2-neg MBC might respond differently according to the molecular intrinsic subtype, with Luminal A and B tumors being sensitive to both CDKi, Basal-like being insensitive to endocrine therapy, irrespective of CDKi, and HER2-enriched tumors showing a benefit only with ribociclib-based therapy.

Clinical case

We hereby present a paradigmatic clinical case of a woman affected by a relapsed HR+/HER2-neg MBC with bone and nodal lesions, presenting with a visceral crisis in the form of lymphangitis carcinomatosis and diagnosed with a molecularly HER2-enriched tumor, successfully treated with upfront ribociclib + fulvestrant. The patient experienced a complete symptomatic and radiologic remission of the lymphangitis with a partial response as best response, according to RECIST 1.1 criteria. The progression-free survival (PFS) was of 20 months, in line with the median PFS observed in the ribociclib + fulvestrant pivotal trial, where, however, patients with visceral crisis had been excluded.

Conclusions

This clinical case confirms in the real-world setting that non-luminal subtypes can be found in HR+/HER2-neg disease and may have potential therapeutic implications in the metastatic setting. It also questions the recommendation of upfront chemotherapy in the case of a visceral crisis in the era of CDKi-based regimens. These issues merit further evaluation in prospective and larger studies.

Pathological complete response, long-term outcomes, and recurrence patterns in HER2-low versus HER2-zero breast cancer after neoadjuvant chemotherapy

BACKGROUND

The interest in HER2-low breast cancer (BC) has increased in recent years with the development of novel anti-HER2 antibody-drug conjugates. Here, we investigated the clinical outcomes and relapse patterns of patients with HER2-low or -zero BCs in an Asian population.

METHODS

We retrospectively identified HER2-low or -zero BC patients with stage I-III tumours who were treated with neoadjuvant chemotherapy and underwent curative surgery, between 2014 and 2018 at Asan Medical Center, Seoul, Korea.

RESULTS

A total of 818 and 754 HER2-zero and HER2-low BC patients, respectively, were consecutively included in this analysis. The HER2-low group had more hormone receptor [HR]-positive patients (81% versus 56%, P < 0.001). The HER2-zero group had a higher proportion of patients who achieved pathological complete response (pCR) (14.7% versus 9.8%, P = 0.003); however, no significant differences of pCR rate by HER2 status were identified in the HR-positive (P = 0.4) and HR-negative groups (P = 0.3) when analysed separately. The HER2-low BC cases had higher 5-year overall survival (OS) and disease-free survival (DFS) rates (P < 0.001 for OS; P = 0.002 for DFS); however, no differences were observed in terms of OS and DFS by HER2 status in the HR-positive group (P = 0.21 for OS and P = 0.66 for DFS).

CONCLUSIONS

Our current findings do not support that HER2-low BC had different biology and clinical features compared to HER2-zero BC in patients who treated with neoadjuvant chemotherapy. However, the prognostic impact of HER2-low status in BC remains controversial; thus warranting further research.

Tailoring adjuvant endocrine therapy in early breast cancer: When, how, and how long?

Endocrine therapy represents the gold standard for the adjuvant treatment of luminal-like early breast cancer, but its personalization is still a major point of debate. To define the most appropriate therapeutic strategy, both the patient's menopausal status at the moment of diagnosis and the individual risk of disease recurrence should be taken into account. Five years of therapy with tamoxifen represent the standard of care for low-risk pre/perimenopausal patients, whilst the combination of ovarian suppression with tamoxifen or an aromatase inhibitor should be considered for high-risk patients. Also, to high-risk patients, an extended strategy can be proposed. Postmenopausal patients, instead, should receive an upfront aromatase inhibitor and an extended strategy can be considered for a high risk of disease recurrence. Aim of this review is to set a focus on the major studies investigating the optimal type and duration of adjuvant endocrine therapy and evaluate emerging options.