Neoadjuvant endocrine therapy use in early stage breast cancer during the covid-19 pandemic

Breast cancer incidence, stage distribution, and treatment shifts during the 2020 COVID-19 pandemic: a nationwide population-level study

BACKGROUND

The first COVID-19 wave in 2020 necessitated temporary suspension of non-essential medical services including organized cancer screening programs in Belgium. This study assessed the impact of the pandemic on breast cancer (BC) incidence, stage at diagnosis, and management in Belgium in 2020.

METHODS

All Belgian residents diagnosed with in situ or invasive BC in 2015-2020 in the nationwide, population-based cancer registry database were included. Incidence trends for 2015-2019 were extrapolated to predict incidence and stage distribution for 2020 and compared with the observed values. National healthcare reimbursement data were used to examine treatment strategies. Exact tumor diameter and nodal involvement, extracted from pathology reports, were analyzed for 2019 and 2020.

RESULTS

74,975 tumors were selected for analysis of incidence and clinical stage. Invasive BC incidence declined by -5.0% in 2020, with a drop during the first COVID-19 wave (Mar-Jun; -23%) followed by a rebound (Jul-Dec; +7%). Predicted and observed incidence (in situ + invasive) was not different in patients < 50 years. In the 50-69 and 70 + age groups, significant declines of -4.1% and - 8.4% respectively were found. Excess declines were seen in clinical stage 0 and I in Mar-Jun, without excess increases in clinical stage II-IV tumors in Jul-Dec. There was no increase in average tumor diameter or nodal involvement in 2020. Patients diagnosed in Mar-Jun received significantly more neoadjuvant therapy, particularly neoadjuvant hormonal therapy for patients with clinical stage I-II BC.

CONCLUSIONS

BC incidence decline in 2020 in Belgium was largely restricted to very early-stage BC and patients aged 50 and over. Delayed diagnosis did not result in an overall progression to higher stage at diagnosis in 2020. Observed treatment adaptations in Belgium were successful in prioritizing patients for surgery while preventing tumor progression in those with surgical delay. Continuation of monitoring BC incidence and stage in the future is crucial.

Neoadjuvant Chemotherapy Is Effective in Those Infected With SARS-CoV-2: The Real-World Experience of a Large Chinese Breast Cancer Center

PURPOSE

During the major shift in China's policies on coronavirus disease 2019 (COVID-19), many residents will be infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) over a short period, including a few patients with breast cancer undergoing neoadjuvant chemotherapy (NAC). Moreover, it is unknown whether this comorbidity affects the efficacy of NAC for breast cancer and the patient's psychological state and quality of life (QOL). This study aims to answer these questions.

METHODS

The clinical data of 2,793 patients with breast cancer who received NAC at The Affiliated Hospital of Qingdao University were retrospectively collected. The infected and non-infected groups were divided according to whether they were infected with COVID-19 during NAC. Propensity score matching was used to reduce patient selection bias. The effectiveness, psychological well-being, and QOL of the two groups were compared.

RESULTS

No discernible differences were observed in the pathological complete response rates (p = 0.307) and major histological responses rate (p = 0.398) between the infected and non-infected groups. Following the full course of NAC, the Functional Assessment of Cancer Treatment General (p < 0.001) and Functional Assessment of Cancer Therapy for Breast Cancer (p < 0.001) were lower in the infected group than the non-infected group, the Hospital Anxiety and Depression Scale (HADS) anxiety scale (p < 0.001) and HADS depression scale (p < 0.001) were considerably higher in the infected group than the non-infected group.

CONCLUSION

With timely treatment and effective medical management, SARS-CoV-2 does not appear to affect the efficacy of NAC; however, it can significantly affect the QOL of patients and increase their psychological distress. Therefore, in addition to a timely assessment of the efficacy of NAC, it is necessary to dynamically understand the patient's psychological state and QOL.

The Impact of the COVID-19 Pandemic on Adherence to Endocrine Therapy for Breast Cancer in Catalonia (Spain)

Purpose. To assess the impact of the COVID-19 pandemic on adherence to oral endocrine therapy in patients diagnosed with breast cancer in the public healthcare system in Catalonia (Spain). Methods. Retrospective cohort study in patients starting endocrine therapy from 2017 to 2021. Adherence was measured during the first year of treatment, and the impact of the pandemic was calculated according to the calendar year and whether the first year of treatment included the peak period of the pandemic in our setting (March-September 2020). Analyses were performed using a chi-square test and multivariable logistic regression, with results stratified by year, age group, and drug type. Results. Mean overall adherence during the first year of treatment was 89.6% from 2017 to 2021. In contrast, the patients who started treatment in 2019 and 2020 and whose treatment included the peak pandemic period presented an adherence of 87.0% and 86.5%, respectively. Young age and tamoxifen or combination therapy were predictors of low adherence. An increase in neoadjuvant therapy was also observed in 2020. Conclusions. The COVID-19 pandemic had only a modest impact on adherence to endocrine therapy (≈3%), despite the enormous disruptions for patients, the healthcare system in general, and cancer care in particular that were occurring in that period.

Differential response to neoadjuvant endocrine therapy for Black/African American and White women in NCDB

PURPOSE

Compared to White women, there are higher mortality rates in Black/African American (BAA) women with hormone receptor-positive breast cancer (HR + BC) which may be partially due to differences in treatment resistance. We assessed factors associated with response to neoadjuvant endocrine therapy (NET).

METHODS

The National Cancer Database (NCDB) was queried for women with clinical stage I-III HR + BC diagnosed 2006-2017 and treated with NET. Univariate and multivariate analyses described associations between the sample, duration of NET, and subsequent treatment response, defined by changes between clinical and pathological staging.

RESULTS

The analytic sample included 9864 White and 1090 BAA women. Compared to White women, BAA women were younger, had more co-morbidities, were higher stage at presentation, and more likely to have > 24 weeks of NET. After excluding those with unknown pT/N/M, 3521 White and 365 BAA women were evaluated for NET response. On multivariate analyses, controlling for age, stage, histology, HR positivity, and duration of NET, BAA women were more likely to downstage to pT0/Tis (OR 3.0, CI 1.2-7.1) and upstage to Stage IV (OR 2.4, CI 1.002-5.6). None of the women downstaged to pT0/Tis presented with clinical stage III disease; only 2 of the women upstaged to Stage IV disease presented with clinical Stage I disease.

CONCLUSION

Independent of NET duration and clinical stage at presentation, BAA women were more likely to experience both complete tumor response and progression to metastatic disease. These results suggest significant heterogeneity in tumor biology and warrant a more nuanced therapeutic approach to HR + BC.

Neoadjuvant endocrine therapy in ER-positive breast cancer: evolution, indication, and tailored treatment strategy

In recent years, endocrine therapy (ET), an effective systemic treatment for the management of estrogen receptor (ER)-positive breast cancers, has regained interest as a neoadjuvant therapy based on evidence that ET can fulfill the aim of neoadjuvant systemic treatment for tumor shrinkage as well as elucidate important clinical information on endocrine sensitivity that enables the prognostication of patients. Moreover, neoadjuvant endocrine therapy (NET) potentially provides an opportunity for early assessment of the clinical efficacy of novel agents. Furthermore, recently reported trials have generated evidence for a more tailored approach for perioperative management of ER-positive breast cancer using clinical and molecular biomarkers, and this has provided a rationale that enables the broadening of clinical indications for NET. This review discusses the current evidence for NET, the evolution of NET trials, clinical indications, and NET-based treatment strategies.

COVID-19 and Breast Cancer: Analysis of Surgical Management of a Large Referral Center during the 2020-2021 Pandemic Period

BACKGROUND

Coronavirus disease-19 (COVID-19) has spread worldwide since December 2019 and was officially declared a pandemic in March 2020. Due to the rapid transmission and the high fatality rate, drastic emergency restrictions were issued, with a negative impact on routine clinical activities. In particular, in Italy, many authors have reported a reduction in the number of breast cancer diagnoses and critical problems in the management of patients who accessed the breast units during the dramatic first months of the pandemic. Our study aims to analyze the global impact of COVID-19 in the two years of the pandemic (2020-2021) on the surgical management of breast cancer by comparing them with the previous two years.

METHODS

In our retrospective study, we analyzed all cases of breast cancer diagnosed and surgically treated at the breast unit of "Città della Salute e della Scienza" in Turin, Italy, making a comparison between the 2018-2019 pre-pandemic period and the 2020-2021 pandemic period.

RESULTS

We included in our analysis 1331 breast cancer cases surgically treated from January 2018 to December 2021. A total of 726 patients were treated in the pre-pandemic years and 605 in the pandemic period (-121 cases, 9%). No significant differences were observed regarding diagnosis (screening vs. no screening) and timing between radiological diagnosis and surgery for both in situ and invasive tumors. There were no variations in the breast surgical approach (mastectomy vs. conservative surgery), while a reduction in axillary dissection compared to the sentinel lymph node in the pandemic period was observed (p-value < 0.001). Regarding the biological characteristics of breast cancers, we observed a greater number of grades 2-3 (p-value = 0.007), pT stage 3-4 breast cancer surgically treated without previous neoadjuvant chemotherapy (p-value = 0.03), and a reduction in luminal B tumors (p-value = 0.007).

CONCLUSIONS

Overall, we report a limited reduction in surgical activity for breast cancer treatment considering the entire pandemic period (2020-2021). These results suggest a prompt resumption of surgical activity similar to the pre-pandemic period.

Using Oncotype DX breast recurrence score® assay to define the role of neoadjuvant endocrine therapy in early-stage hormone receptor-positive breast cancer

PURPOSE

The role of neoadjuvant endocrine therapy in the treatment of patients with early-stage, hormone receptor-positive (HR +) breast cancer is not well defined. Tools to better determine which patients may benefit from neoadjuvant endocrine therapy versus chemotherapy or upfront surgery remain an unmet need.

METHODS

We assessed the rate of clinical and pathologic complete response (cCR, pCR) among a pooled cohort of patients with early-stage HR + breast cancer who had been randomized to neoadjuvant endocrine therapy or neoadjuvant chemotherapy in two earlier studies to understand better how outcomes varied by Oncotype DX Breast Recurrence Score® assay.

RESULTS

We observed that patients with intermediate RS results had no statistically significant differences in pathologic outcomes at the time of surgery based on whether they received neoadjuvant endocrine therapy or neoadjuvant chemotherapy, suggesting that a subgroup of women with a RS 0-25 may omit chemotherapy without compromising outcomes.

CONCLUSION

These data suggest that Recurrence Score® (RS) results may serve as a useful tool in treatment decision-making in the neoadjuvant setting.

Neoadjuvant endocrine therapy in postmenopausal women with HR+/HER2- breast cancer

INTRODUCTION

While endocrine therapy is the standard-of-care adjuvant treatment for hormone receptor-positive (HR+) breast cancers, there is also extensive evidence for the role of pre-operative (or neoadjuvant) endocrine therapy (NET) in HR+ postmenopausal women.

AREAS COVERED

We conducted a thorough review of the published literature, to summarize the evidence to date, including studies of how NET compares to neoadjuvant chemotherapy, which NET agents are preferable, and the optimal duration of NET. We describe the importance of on-treatment assessment of response, the different predictors available (including Ki67, PEPI score, and molecular signatures) and the research opportunities the pre-operative setting offers. We also summarize recent combination trials and discuss how the COVID-19 pandemic led to increases in NET use for safe management of cases with deferred surgery and adjuvant treatments.

EXPERT OPINION

NET represents a safe and effective tool for the management of postmenopausal women with HR+/HER2- breast cancer, enabling disease downstaging and a wider range of surgical options. Aromatase inhibitors are the preferred NET, with evidence suggesting that longer regimens might yield optimal results. However, NET remains currently underutilised in many territories and institutions. Further validation of predictors for treatment response and benefit is needed to help standardise and fully exploit the potential of NET in the clinic.

An examination of health care utilization during the COVID-19 pandemic among women with early-stage hormone receptor-positive breast cancer

BACKGROUND

Women undergoing treatment for breast cancer require frequent clinic visits for maintenance of therapy. With COVID-19 causing health care disruptions, it is important to learn about how this population's access to health care has changed. This study compares self-reported health care utilization and changes in factors related to health care access among women treated at a cancer center in the mid-South US before and during the pandemic.

METHODS

Participants (N = 306) part of a longitudinal study to improve adjuvant endocrine therapy (AET) adherence completed pre-intervention baseline surveys about their health care utilization prior to AET initiation. Questions about the impact of COVID-19 were added after the pandemic started assessing financial loss and factors related to care. Participants were categorized into three time periods based on the survey completion date: (1) pre-COVID (December 2018 to March 2020), (2) early COVID (April 2020 - December 2020), and later COVID (January 2021 to June 2021). Negative binomial regression analyses used to compare health care utilization at different phases of the pandemic controlling for patient characteristics.

RESULTS

Adjusted analyses indicated office visits declined from pre-COVID, with an adjusted average of 17.7 visits, to 12.1 visits during the early COVID period (p = 0.01) and 9.9 visits during the later COVID period (p < 0.01). Hospitalizations declined from an adjusted average 0.45 admissions during early COVID to 0.21 during later COVID, after vaccines became available (p = 0.05). Among COVID period participants, the proportion reporting changes/gaps in health insurance coverage increased from 9.5% participants during early-COVID to 14.8% in the later-COVID period (p = 0.05). The proportion reporting financial loss due to the pandemic was similar during both COVID periods (34.3% early- and 37.7% later-COVID, p = 0.72). The proportion of participants reporting delaying care or refilling prescriptions decreased from 15.2% in early-COVID to 4.9% in the later-COVID period (p = 0.04).

CONCLUSION

COVID-19 caused disruptions to routine health care for women with breast cancer. Patients reported having fewer office visits at the start of the pandemic that continued to decrease even after vaccines were available. Fewer patients reported delaying in-person care as the pandemic progressed.

Comparison of Use of Neoadjuvant Systemic Treatment for Breast Cancer and Short-term Outcomes Before vs During the COVID-19 Era in Ontario, Canada

IMPORTANCE

In response to an increase in COVID-19 infection rates in Ontario, several systemic treatment (ST) regimens delivered in the adjuvant setting for breast cancer were temporarily permitted for neoadjuvant-intent to defer nonurgent breast cancer surgical procedures.

OBJECTIVE

To examine the use and compare short-term outcomes of neoadjuvant-intent vs adjuvant ST in the COVID-19 era compared with the pre-COVID-19 era.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective population-based cohort study in Ontario, Canada. Patients with cancer starting selected ST regimens in the COVID-19 era (March 11, 2020, to September 30, 2020) were compared to those in the pre-COVID-19 era (March 11, 2019, to March 10, 2020). Patients were diagnosed with breast cancer within 6 months of starting systemic therapy.

MAIN OUTCOMES AND MEASURES

Estimates were calculated for the use of neoadjuvant vs adjuvant ST, the likelihood of receiving a surgical procedure, the rate of emergency department visits, hospital admissions, COVID-19 infections, and all-cause mortality between treatment groups over time.

RESULTS

Among a total of 10 920 patients included, 7990 (73.2%) started treatment in the pre-COVID-19 era and 7344 (67.3%) received adjuvant ST; the mean (SD) age was 61.6 (13.1) years. Neoadjuvant-intent ST was more common in the COVID-19 era (1404 of 2930 patients [47.9%]) than the pre-COVID-19 era (2172 of 7990 patients [27.2%]), with an odds ratio of 2.46 (95% CI, 2.26-2.69; P < .001). This trend was consistent across a range of ST regimens, but differed according to patient age and geography. The likelihood of receiving surgery following neoadjuvant-intent chemotherapy was similar in the COVID-19 era compared with the pre-COVID-19 era (log-rank P = .06). However, patients with breast cancer receiving neoadjuvant-intent hormonal therapy were significantly more likely to receive surgery in the COVID-19 era (log-rank P < .001). After adjustment, there were no significant changes in the rate of emergency department visits over time between patients receiving neoadjuvant ST, adjuvant ST, or ST only during the ST treatment period or postoperative period. Hospital admissions decreased in the COVID-19 era for patients who received neoadjuvant ST compared with adjuvant ST or ST alone (P for interaction = .01 for both) in either setting.

CONCLUSIONS AND RELEVANCE

In this cohort study, patients were more likely to start neoadjuvant ST in the COVID-19 era, which varied across the province and by indication. There was limited evidence to suggest any substantial impact on short-term outcomes.

Breast cancer diagnosis and treatment during the COVID-19 pandemic in a nationwide, insured population

Purpose

The early months of the COVID-19 pandemic led to reduced cancer screenings and delayed cancer surgeries. We used insurance claims data to understand how breast cancer incidence and treatment after diagnosis changed nationwide over the course of the pandemic.

Methods

Using the Optum Research Database from January 2017 to March 2021, including approximately 19 million US adults with commercial health insurance, we identified new breast cancer diagnoses and first treatment after diagnosis. We compared breast cancer incidence and proportion of newly diagnosed patients receiving pre-operative systemic therapy pre-COVID, in the first 2 months of the COVID pandemic and in the later part of the COVID pandemic.

Results

Average monthly breast cancer incidence was 19.3 (95% CI 19.1–19.5) cases per 100,000 women and men pre-COVID, 11.6 (95% CI 10.8–12.4) per 100,000 in April–May 2020, and 19.7 (95% CI 19.3–20.1) per 100,000 in June 2020–February 2021. Use of pre-operative systemic therapy was 12.0% (11.7–12.4) pre-COVID, 37.7% (34.9–40.7) for patients diagnosed March–April 2020, and 14.8% (14.0–15.7) for patients diagnosed May 2020–January 2021. The changes in breast cancer incidence across the pandemic did not vary by demographic factors. Use of pre-operative systemic therapy across the pandemic varied by geographic region, but not by area socioeconomic deprivation or race/ethnicity.

Conclusion

In this US-insured population, the dramatic changes in breast cancer incidence and the use of pre-operative systemic therapy experienced in the first 2 months of the pandemic did not persist, although a modest change in the initial management of breast cancer continued.

Are sex hormones promising candidates to explain sex disparities in the COVID-19 pandemic?

Emerging evidence suggests that the novel Coronavirus disease-2019 (COVID-19) is deadlier for men than women both in China and in Europe. Male sex is a risk factor for COVID-19 mortality. The meccanisms underlying the reduced morbidity and lethality in women are currently unclear, even though hypotheses have been posed (Brandi and Giustina in Trends Endocrinol Metab. 31:918-27, 2020). This article aims to describe the role of sex hormones in sex- and gender-related fatality of COVID-19. We discuss the possibility that potential sex-specific mechanisms modulating the course of the disease include both the androgen- and the estrogen-response cascade. Sex hormones regulate the respiratory function, the innate and adaptive immune responses, the immunoaging, the cardiovascular system, and the entrance of the virus in the cells. Recommendations for the future government policies and for the management of COVID-19 patients should include a dimorphic approach for males and females. As the estrogen receptor signaling appears critical for protection in women, more studies are needed to translate the basic knowledge into clinical actions. Understanding the etiological bases of sexual dimorphism in COVID-19 could help develop more effective strategies in individual patients in both sexes, including designing a good vaccine.

Effect of the COVID‐19 pandemic on surgical oncology practice—Results of an SSO survey

Background and Objectives

The COVID‐19 pandemic significantly affected healthcare delivery, shifting focus away from nonurgent care. The aim of this study was to examine the impact of the pandemic on the practice of surgical oncology.

Methods

A web‐based survey of questions about changes in practice during the COVID‐19 pandemic was approved by the Society of Surgical Oncology (SSO) Research and Executive Committees and sent by SSO to its members.

Results

A total of 121 SSO members completed the survey, 77.7% (94/121) of whom were based in the United States. Breast surgeons were more likely than their peers to refer patients to neoadjuvant therapy (p = 0.000171). Head and neck surgeons were more likely to refer patients to definitive nonoperative treatment (p = 0.044), while melanoma surgeons were less likely to do so (p = 0.029). In all, 79.2% (95/120) of respondents are currently using telemedicine. US surgeons were more likely to use telemedicine (p = 0.004). Surgeons believed telemedicine is useful for long‐term/surveillance visits (70.2%, 80/114) but inappropriate (50.4%, 57/113) for new patient visits.

Conclusion

COVID‐19 pandemic resulted in increased use of neoadjuvant therapy, delays in operative procedures, and increased use of telemedicine. Telemedicine is perceived to be most efficacious for long‐term/surveillance visits or postoperative visits.

Estrogen and Estrogen Receptor Modulators: Potential Therapeutic Strategies for COVID-19 and Breast Cancer

Owing to the ongoing coronavirus disease 2019 (COVID-19) pandemic, we need to pay a particular focus on the impact of coronavirus infection on breast cancer patients. Approximately 70% of breast cancer patients express estrogen receptor (ER), and intervention therapy for ER has been the primary treatment strategy to prevent the development and metastasis of breast cancer. Recent studies have suggested that selective estrogen receptor modulators (SERMs) are a potential therapeutic strategy for COVID-19. With its anti-ER and anti-viral combined functions, SERMs may be an effective treatment for COVID-19 in patients with breast cancer. In this review, we explore the latent effect of SERMs, especially tamoxifen, and the mechanism between ER and virus susceptibility.

Analysis of the Impact of the COVID-19 Pandemic on the Multidisciplinary Management of Breast Cancer: Review from the American Society of Breast Surgeons COVID-19 and Mastery Registries

Background

The coronavirus disease 2019 (COVID-19) pandemic has resulted in rapid and regionally different approaches to breast cancer care.

Methods

In order to evaluate these changes, a COVID-19-specific registry was developed within the American Society of Breast Surgeons (ASBrS) Mastery that tracked whether decisions were usual or modified for COVID-19. Data on patient care entered into the COVID-19-specific registry and the ASBrS Mastery registry from 1 March 2020 to 15 March 2021 were reviewed.

Results

Overall, 177 surgeons entered demographic and treatment data on 2791 patients. Mean patient age was 62.7 years and 9.0% (252) were of African American race. Initial consultation occurred via telehealth in 6.2% (173) of patients and 1.4% (40) developed COVID-19. Mean invasive tumor size was 2.1 cm and 17.8% (411) were node-positive. In estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2−) disease, neoadjuvant endocrine therapy (NET) was used as the usual approach in 6.9% (119) of patients and due to COVID-19 in an additional 31% (542) of patients. Patients were more likely to receive NET due to COVID-19 with increasing age and if they lived in the Northeast or Southeast (odds ratio [OR] 1.1, 2.3, and 1.7, respectively; p < 0.05). Genomic testing was performed on 51.5% (781) of estrogen-positive patients, of whom 20.7% (162) had testing on the core due to COVID-19. Patients were less likely to have core biopsy genomic testing due to COVID-19 if they were older (OR 0.89; p = 0.01) and more likely if they were node-positive (OR 4.0; p < 0.05). A change in surgical approach due to COVID-19 was reported for 5.4% (151) of patients.

Conclusion

The ASBrS COVID-19 registry provided a platform for monitoring treatment changes due to the pandemic, highlighting the increased use of NET.

Neoadjuvant Endocrine Therapy as an Alternative to Neoadjuvant Chemotherapy Among Hormone Receptor-Positive Breast Cancer Patients: Pathologic and Surgical Outcomes

Background

Neoadjuvant chemotherapy (NCT) is considered more effective in downstaging hormone receptor-positive (HR+) breast cancer than neoadjuvant endocrine therapy (NET), particularly in node-positive disease. This study compared breast and axillary response and survival after NCT and NET in HR+ breast cancer.

Methods

Based on American College of Surgeons Oncology Group (ACOSOG) Z1031 criteria, women age 50 years or older with cT2-4 HR+ breast cancer who underwent NET or NCT and surgery were identified in the National Cancer Database 2010–2016. Chi-square and logistic regression analysis determined differences between the NCT and NET groups and therapy response, including downstaging and pathologic complete response (pCR, ypT0/is and ypN0).

Results

Of 19,829 patients, 14,025 (70.7%) received NCT and 5804 (29.3%) received NET. The NET patients were older (mean age, 68.9 vs. 60.3; P < 0.001) and had greater comorbidity (1+ Charlson–Deyo score, 21% vs. 16%; P < 0.001). Therapy achieved T downstaging (any) for 58% of the patients with NCT versus 40.5% of the patients with NET, and in-breast pCR was achieved for 9.3% of the NCT versus 1.3% of the NET patients (P < 0.001). Approximately half of the mastectomy procedures could have been potentially avoided for the patients with in-breast pCR (53.6% of the NCT and 43.8% of the NET patients). For the cN+ patients, N downstaging (any) was 29% for the NCT patients versus 18.3% for the NET patients (P < 0.001), and nodal pCR was achieved for 20.3% of the NCT versus 13.5% of the NET patients (P < 0.001). Among those with nodal pCR, axillary lymph node dissection (ALND) still was performed for 56% of the patients after NCT and 45% of the patients after NET.

Conclusions

Although the response rates after NCT were higher, NET achieved both T and N downstaging and pCR. Neoadjuvant endocrine therapy can be used to de-escalate surgery for patients who cannot tolerate NCT or when chemotherapy may not be effective based on genomic testing.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-021-10459-3.