Hormone Receptor-positive Early Breast Cancer Research Articles

Abstract PO3-17-11: The Utility of Oncotype DX in Grade 1 Hormone Receptor-Positive Early Breast Cancer: Insights from a Multicentric Real-World Data Study

Abstract Background: The Oncotype Dx (ODX) genomic risk score (RS) has become an essential tool in clinical practice for guiding adjuvant chemotherapy decisions in early-stage hormone receptor-positive (HR+), HER2-negative breast cancer (BC). Since some of the genes evaluated in the genomic RS tests are proliferation-related, the use of the test is less clear in tumors with low proliferation, such as histologic grade 1 tumors or those with a low Ki67-index. In contrast to common understanding, however, ODX RS is determined more strongly by estrogen-related features and only weakly by proliferation markers. Methods: This multicentric real-world data (RWD) study aimed to evaluate the usefulness of (ODX) in patients with grade 1 (G1) HR+, HER2-negative BC. The study population consisted of patients treated between 2009 and 2020 across nine Brazilian cancer centers. Key endpoints included the prevalence of high genomic RS in the histologic grade 1 cohort, recurrence rates based on genomic risk, and invasive disease-free survival (IDFS). Results: A total of 651 patients with HR+, HER2-negative BC who underwent Oncotype Dx testing were evaluated. Among 651 patients evaluated, 128 had HG1 tumors, constituting the focus of this analysis. The majority of patients were aged over 50 years (59.4%), had breast carcinoma of non-special type (75.8%), and Ki67 index lower than 20% (77%). Tumor stage distribution revealed 28.1% T1b, 50% T1c, and 14% T2 cases. Additionally, 74.2% were classified as N0, 9.4% as N1mic, and 16.4% as N1. According to the binary categorization based on Adjuvant! algorithm, 92.2% of patients (n=118) had a low clinical risk. ODx analysis showed that 21.9% had a low RS, 74.2% had an intermediate RS, and only 3.1% had a high RS. Among the few patients with a high genomic RS, only one patient did not receive adjuvant chemotherapy. With a median follow-up of 38.3 months, three patients experienced recurrence, all of whom had an intermediate RS. Among these cases, two patients were younger than 50 years, had low clinical risk, and a genomic RS of 18-24; both had locoregional recurrences. The third patient, aged over 50 years, had high clinical risk, a RS of 12, and had a distant recurrence. The recurrence rates according to Ki67 index were 1.1% for patients with Ki67 index < 20% and 7.1% for those with Ki67 index ≥ 20%. Notably, no recurrences were observed in the high genomic risk group. The estimated 5-year IDFS rate was 96.9% (95% CI 88.2% - 99.2%). Conclusion: In the context of G1 BC and low clinical risk, the utility and cost-effectiveness of ODX may be limited. These findings emphasize the importance of carefully assessing clinical risk when selecting patients for genomic RS tests, thereby optimizing resource utilization. Longer follow-up is planned for this RWD cohort. Citation Format: Renata Colombo Bonadio, Leandro Oliveira, Daniel Batista, Daniela Rosa, Artur Katz, Max Mano, Daniele Assad-Suzuki, Daniel Argolo, Solange Sanches, Rafael Kaliks, Débora Gagliato, Thais Megid, Daniel Musse, Tatiana Correa, Andrea Shimada, Romualdo Barroso-Sousa, Marcelle Cesca, Débora Gaudêncio, Larissa Moura, Julio Araujo, José Bines, Laura Testa. The Utility of Oncotype DX in Grade 1 Hormone Receptor-Positive Early Breast Cancer: Insights from a Multicentric Real-World Data Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-17-11.

Abstract PS16-04: Denosumab as an enhancer of the immune infiltrate in hormone receptor-positive early breast cancer. Subgroup analysis from the D-Biomark window-of-opportunity clinical trial (NCT03691311)

Abstract Background: The receptor activator of nuclear factor κB (RANK) signaling pathway has emerged as a therapeutic target in breast cancer (BC). Recent studies indicate that inhibition of the RANK pathway induces tumor cell differentiation and may enhance the anti-tumor immune response. The D-Biomark clinical trial aims to evaluate the antitumor (antiproliferative and proapoptotic) and immunomodulatory effects of denosumab in HER2-negative early BC. Methods: Patients with early HER2-negative BC scheduled for primary surgery were randomized in a 2:1 ratio to receive two doses of 120 mg denosumab on days 1 and 8 vs no treatment before surgery. Immunohistochemistry (IHC) was used to assess Ki67 (proliferation), cleaved caspase-3 (cell survival), RANK and RANKL. Stromal tumor infiltrating lymphocytes (TILs) and serum markers including free RANKL (sRANKL), tartrate-resistant acid phosphatase 5b (TRACP5b), and osteoprotegerin (OPG) were also analyzed. Paired t-test was used to compare values between core biopsy (biopsy A) and surgical samples (biopsy B). Subgroup analysis by intrinsic subtype was performed on 47 matched cases using PAM50. Results: Between July 2019 and May 2021, we enrolled 60 patients, 58 evaluable, including 10 triple-negative breast cancer (TNBC). The clinicopathologic characteristics of the population at the time of enrollment were well balanced, but the TNBC recruited included 5 out of 10 tumors with a more indolent behavior than the typical tumors of this lineage (apocrine tumors, low cell proliferation). Due to this and the small number of cases, no conclusions can be drawn in this subgroup. RANK expression was detected in 19 tumor cases, while 17 cases expressed RANKL. The treated group showed a decrease in sRANKL (p < 0.000), indicating denosumab activity, while the control group showed no change (p1.0). OPG levels in the experimental group showed a non-significant increase (p0.07), while TRACP5b remained unchanged. Both groups showed a non-clinically relevant increase in cell proliferation (5 percentage points), control p0.04, experimental p0.01. Subgroup analysis of tumors with RANK+ or RANKL+ tumor cells also showed no reduction in Ki67. Cell survival did not decrease in the overall cohort (control p0.05, experimental p0.24), nor in subgroups or in tumors with RANK+ or RANKL+ tumor cells. Denosumab treatment increased TILs in the overall population (control p0.06, experimental p0.0006) and in the subgroups: RANK+ tumors, RANKL+ tumors, premenopausal and postmenopausal, less so in the TNBC group. The subgroup analysis is shown in Table 1. Analysis by intrinsic subtype showed that in the experimental group there was an increase in cases with a change to luminal A lineage (17%) compared to the control group (6%), suggesting a possible cellular differentiation towards less aggressive tumors. Although the number of patients is small, these changes warrant further investigation and highlight the role of denosumab as an immune activator in these luminal tumors known for their low inflammatory infiltrate. Conclusion: Two doses of denosumab prior to surgery did not reduce proliferation or increase apoptosis. However, this short course of denosumab increased TILs in early BC, particularly in luminal tumors, and may induce tumor cell differentiation into luminal A-like tumors. Table. Citation Format: Andrea Vethencourt, Eva Trinidad, Eduard Dorca, Anna Petit, Teresa Soler-Monsó, Agostina Stradella, Cristina Capo, Ander Urriticoechea, Marta Matas, Gema Pérez-Chacon, María Jimenez, Marina Ciscar, Emilia Brizzi, Gonzalo Soria Alcaide, Gonzalo Gomez, Elena Piñeiro, Elvira Purqueras, Amparo Garcia, Ariadna Iserte, M Jesus Pla, Miriam Campos, Miguel Gil-Gil, Sonia Pernas, Eva Gonzalez-Suarez, Catalina Falo. Denosumab as an enhancer of the immune infiltrate in hormone receptor-positive early breast cancer. Subgroup analysis from the D-Biomark window-of-opportunity clinical trial (NCT03691311) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS16-04.

Abstract PO2-01-13: Clinico-Pathological and Molecular Characterization of Early Hormone Receptor-Positive Breast Cancer in Young Women

Abstract Introduction Premenopausal women diagnosed with hormone receptor-positive (HR+)/HER2-negative (HER2-) early breast cancer (EBC) face a significantly higher risk of cancer recurrence and mortality compared to older women, particularly those diagnosed under the age of 40. The underlying causes behind this disparity remain largely unknown. Material and methods We retrospectively select tumour samples from patients (pts) diagnosed with HR+/HER2- EBC at Hospital Clinic (Barcelona, Spain) from May 2014 to March 2020 who had a PAM50/Prosigna assay (Veracyte) previously performed. This assay examines the expression of 50 genes involved in important breast cancer signaling pathways, as well as the intrinsic subtypes (IS) and the Risk of Recurrence (ROR) score. Our primary objective was to compare the distinct clinicopathological and molecular characteristics of HR+/HER2- EBC between two age groups: patients under 40 years old (Young EBC or YEBC) and those 40 years old and above (Older EBC or OEBC). Disease-free survival (DFS) was defined as the time between diagnosis and the first recurrence. Comparisons between groups were carried out using chi-square tests (categorical variables). Additionally, we performed a two-class unpaired Significance Analysis of Microarrays (SAM) with a false discovery rate (FDR) less than 5% to identify genes with significantly different expression between YEBC and OEBC. The statistical significance level was set at less than 0.05. Results A total of 441 tumor samples from 420 patients were included in the analysis, with 5% (22/441) corresponding to YEBC. With a median follow-up of 64.5 months, there were 20 breast cancer (BC) recurrences (4.8%), 12 second cancers (2.9%) and 5 BC-related deaths (1.2%), all occurring in the OEBC group. Table 1 provides an overview of the main clinico-pathological and molecular characteristics. YEBC tended to have larger tumors, with 45.5% (10/22) measuring over 2 cm compared to 36.1% (151/419) in OEBC (p=0.376). YEBC also had a higher proportion of grade 3 tumors (18.18% versus 3.1% in OEBC, p=0.418) and lower expression of estrogen receptor (ER) as determined by immunohistochemistry (mean of 72.28% vs 88.36%, p=0.004). Regarding the PAM50 IS, there was a difference observed between YEBC and OEBC (p < 0.001). Specifically, YEBC patients exhibited a tendency towards a higher proportion of Luminal B tumors (54.6% versus 38.9% in OEBC, p=0.144), as well as non-Luminal subtypes such as Basal-like (18.2% versus 0.95% in OEBC, p< 0.001) and HER2E (4.6% versus 0.7% in OEBC, p=0.186). YEBC tended to have higher ROR (p=0.167), and to receive chemotherapy in a higher proportion, especially in the intermediate-risk group (p=0.004). In YEBC tumours, SAM analysis (p < 0.05) showed an overexpression of genes mainly related with proliferation (i.e., RRM2, MELK, MIK67), cell cycle progression (i.e., KNTC2, CDC20, MYBL2) and apoptosis inhibition (i.e., BIRC5). In OEBC there were an overexpression of genes related with the oestrogen receptor-signalling pathway (i.e., ESR1, NAT1, FOXA1, PGR). Luminal B tumours in YEBC showed an upregulation of genes related to proliferation, migration, and poor prognosis (i.e., KRT17, KRT5) compared to OEBC. However, since there were no recurrences in the YEBC group, differences in terms of DFS between the groups could not be calculated. Principio del formulario Final del formulario Conclusions YEBC exhibited a more advanced stage and a more aggressive intrinsic phenotype compared to OEBC. Additionally, these tumors showed a tendency to upregulate genes involved in proliferation, cell cycle progression, and survival, while downregulating genes related to hormone signaling pathways. These molecular characteristics may help explain the worse prognosis of YEBC compared to OEBC. However, further research is necessary to delve into the differential genomic characteristics that contribute to the unfavorable prognosis observed in patients diagnosed with HR+ EBC before the age of 40. Key clinical and molecular features in 441 biopsies Citation Format: Francisco Javier Muñoz-Carrillo, José Antonio Sola, Carme Crous, Esther Sanfeliu, Isabel Garcia-Fructuoso, Elia Seguí, Teresa Gorría, Raquel Gómez-Bravo, Barbara Adamo, Tomás Pascual, Olga Martínez-Sáez, Francesco Schettini, Pablo Rivera, Rosalía Cayuela, Montserrat Muñoz, Núria Chic, Maria Vidal. Clinico-Pathological and Molecular Characterization of Early Hormone Receptor-Positive Breast Cancer in Young Women [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-01-13.

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.

Comparative efficacy and safety of extended adjuvant endocrine therapy for hormone receptor-positive early breast cancer: a Bayesian network meta-analysis.

Optimal extended adjuvant endocrine therapy (ET) duration and strategy for hormone receptor-positive (HR +) early breast cancer remain unclear. In this network meta-analysis (NMA), the efficacy and safety of all available extended adjuvant ETs were compared and ranked. PubMed, Embase, and Cochrane Library and abstracts presented at ASCO, SABCS, and ESMO were searched on March 5, 2022. Fourteen randomized controlled trials (RCTs) comprising eight extended adjuvant ETs for HR + breast cancer and 38,070 patients were analyzed. Main outcomes were disease-free survival (DFS), overall survival (OS), grade ≥ 3 adverse events (AEs), and contralateral breast cancer (CBC). Direct and indirect comparisons were integrated via Bayesian NMA. Hierarchical cluster analysis was performed to jointly rank efficacy and safety outcomes. Compared with that of 5year ET, extended 10year aromatase inhibitor (AI) treatment provided the greatest DFS benefit (HR = 0.45, 95%CrI 0.23-0.83), whereas no strategy differed significantly in terms of the other main outcomes. Extended 10year AI treatment was the preferred strategy for DFS improvement and CBC prevention (surface under the cumulative ranking curve: 93.51% and 91.29% probability, respectively). All strategies had comparable safeties (grade ≥ 3 AEs). Compared with that of 5year ET, 10year extended AI significantly increased arthralgia (OR = 1.65, 95%CrI 1.02-2.93) and osteoporosis (OR = 3.33, 95%CrI 1.19-9.68). Extended 10year AI therapy may be optimal for HR + early breast cancer given its relatively high efficacy and safety.

Cost-Effectiveness Analysis of Adjuvant Endocrine Therapy With Ovarian Suppression in Premenopausal Patients With Hormone Receptor-Positive Early Breast Cancer in China

PurposeEndocrine therapy combined with ovarian function suppression (OFS) is recommended in intermediate- or high-risk patients among premenopausal women with hormone receptor-positive early breast cancer. However, in China, the cost-effectiveness of this strategy compared with endocrine therapy alone is unclear. This study aimed to evaluate the long-term cost-effectiveness of tamoxifen (TAM), TAM+OFS, and exemestane plus OFS (EXE+OFS). MethodsOn the basis of prognostic data from the Suppression of Ovarian Function Trial (SOFT), cost data from the Hospital Information System of the West China Hospital of Sichuan University, and health utility values from the published literature, a Markov model was established. The incremental cost-effectiveness ratio (ICER) was used to compare the treatment strategies. ResultsIn a 25-year simulation of adjuvant therapy in Chinese women with early breast cancer, the total costs of TAM, TAM+OFS, and EXE+OFS were $7821, $9318, and $9445, respectively. The quality-adjusted life-years (QALYs) were 11.615, 11.896, and 11.734 years, respectively. Compared with TAM, the ICERs of TAM+OFS and EXE+OFS were $5,327.4021/QALY and $13,647.0588/QALY, respectively. The ICERs of TAM+OFS and EXE+OFS were below the threshold of $32,517/QALY. The reliability and stability of the simulation results were verified using Monte Carlo simulation and sensitivity analysis. ConclusionIn the context of limited resources in China, TAM+OFS and EXE+OFS are cost-effective options compared with TAM.

Insights adjusting for non-adherence in randomized clinical trials: a reanalysis of an adjuvant trial of tamoxifen duration in early breast cancer

BackgroundSeveral randomized clinical trials provide evidence of the survival benefit of extended adjuvant tamoxifen in women with estrogen receptor (ER)-positive early breast cancer (BC). However, non-adherence may lead to underestimate treatment effects using intention to treat (ITT) methods. We reanalyzed a randomized trial using contemporary statistical methods adjusting for non-adherence.MethodsThe TAM01 study was a phase 3 trial including women with early BC, who had completed 2–3 years of adjuvant tamoxifen between 1986 and 1995. Participants were randomly assigned to continue tamoxifen up to 10 years or to discontinue the treatment at randomization. Invasive disease-free survival (iDFS) and overall survival (OS) were estimated using marginal structural models (MSM) and rank preserving structural failure time model (RPSFTM).ResultsOf 3830 patients enrolled, 2485 were randomized to extended tamoxifen, and 1345 to treatment discontinuation. The 10-year non-adherence rate in the extended group was 27.2%. Among women with ER-positive BC (n = 2402), extended tamoxifen was associated with a 45% and 21% relative improvement in iDFS by MSM and RPSFTM, respectively (Hazard Ratio (HR), 0.55; 95% Confidence Interval (CI), 0.48–0.64 and HR, 0.79; 95%CI, 0.67–0.95, respectively), a considerable greater benefit than in the ITT analysis (HR, 0.90; 95%CI, 0.81–0.99). The OS reanalysis revealed a substantial benefit of extended tamoxifen (MSM: HR, 0.70; 95%CI, 0.59–0.83; RPSFTM: HR, 0.85; 95%CI, 0.67–1.04), compared to the ITT analyses (HR, 0.94; 95%CI, 0.84–1.07).ConclusionThis analysis emphasizes both the importance of adherence to hormonotherapy in hormone-receptor positive early BC and the usefulness of more complex statistical analyses.

Impact of BMI in Patients With Early Hormone Receptor-Positive Breast Cancer Receiving Endocrine Therapy With or Without Palbociclib in the PALLAS Trial.

BMI affects breast cancer risk and prognosis. In contrast to cytotoxic chemotherapy, CDK4/6 inhibitors are given at a fixed dose, irrespective of BMI or weight. This preplanned analysis of the global randomized PALLAS trial investigates the impact of BMI on the side-effect profile, treatment adherence, and efficacy of palbociclib. Patients were categorized at baseline according to WHO BMI categories. Neutropenia rates were assessed with univariable and multivariable logistic regression. Time to early discontinuation of palbociclib was analyzed with Fine and Gray competing risk models. Unstratified Cox models were used to investigate the association between BMI category and time to invasive disease-free survival (iDFS). 95% CIs were derived. Of 5,698 patients included in this analysis, 68 (1.2%) were underweight, 2,082 (36.5%) normal weight, 1,818 (31.9%) overweight, and 1,730 (30.4%) obese at baseline. In the palbociclib arm, higher BMI was associated with a significant decrease in neutropenia (unadjusted odds ratio for 1-unit change, 0.93; 95% CI, 0.91 to 0.94; adjusted for age, race ethnicity, region, chemotherapy use, and Eastern Cooperative Oncology Group at baseline, 0.93; 95% CI, 0.92 to 0.95). This translated into a significant decrease in treatment discontinuation rate with higher BMI (adjusted hazard ratio [HR] for 10-unit change, 0.75; 95% CI, 0.67 to 0.83). There was no significant improvement in iDFS with the addition of palbociclib to ET in any weight category (normal weight HR, 0.84; 95% CI, 0.63 to 1.12; overweight HR, 1.10; 95% CI, 0.82 to 1.49; and obese HR, 0.95; 95% CI, 0.69 to 1.30) in this analysis early in follow-up (31 months). This preplanned analysis of the PALLAS trial demonstrates a significant impact of BMI on side effects, dose reductions, early treatment discontinuation, and relative dose intensity. Additional long-term follow-up will further evaluate whether BMI ultimately affects outcome.

Adjuvant Endocrine Therapy in Premenopausal Women With Hormone Receptor-Positive Early-Stage Breast Cancer: Risk Stratification in a Real-World Setting

BackgroundOvarian function suppression (OFS) and hormone therapy (HT) represent an adjuvant option in premenopausal hormone receptor-positive early breast cancer (HR+EBC). The SOFT-TEXT trials showed improved outcomes upon receiving aromatase inhibitors (AIs)/OFS. MethodsIn order to estimate the magnitude of absolute improvements, we conducted a retrospective study applying composite risk (CR) to 237 premenopausal HR+EBC patients. ResultsOverall, 119 of these received tamoxifen (T)/OFS and 118 received AIs/OFS. The median age was 45 years (ys). After a median follow up of 65 months, recurrence was 6.7% in T patients and 10.2% in AI ones. CR (cutoff: 2.67) and ET duration (five-year cutoff) was found to have a significant impact on DFS. Invasive disease-free survival (IDFS) at 5 ys amounted to 82.9% for a CR>2.67 and 95% with CR</=2.67 (p 0.0046). Five-year IDFS was 98.3% in patients who had completed 5-year HT compared to 54.6% of those who had stopped before 5 years (P < .0001). Excluding patients who had discontinued therapy due to disease relapse, IDFS difference at 5 years remained statistically significant (p=0.03) between the two groups, with an iDFS rate of 86.5% at 5 years in the second group. Adverse events of different grades were reported in 116 and 112 patients in the T/OFS group and the AIs/OFS, respectively. Early discontinuation due to toxicity was 3.8%. Seven patients (19.4%) discontinued therapy due to pregnancy desire (6 in the T group, 1 in the AI one); of these, one patient relapsed. ConclusionIn a real-world setting, treatment options for premenopausal patients who are candidates for HT and OFS should take risk status into account. Therefore, every effort should be made to maintain patient adherence to treatment in order to manage toxicities and improve outcomes.

O-277 Safety of pregnancy after early breast cancer in young women with hormone receptor-positive disease: a systematic review and meta-analysis

Abstract Study question Is it safe to have a pregnancy in women with prior history of hormone receptor-positive early breast cancer? Summary answer Pregnancy following breast cancer treatments in young women with history of hormone receptor-positive disease is safe with no detrimental effect on patients’ prognosis. What is known already Breast cancer is the most common malignancy diagnosed in women of reproductive age. Both physicians and patients continue to have concerns about a potential detrimental effect of pregnancy after breast cancer, particularly in the setting of hormone receptor-positive disease. In recent years, several studies have demonstrated the safety of pregnancy after anticancer treatments in breast cancer survivors. Study design, size, duration A systematic literature search of Medline, Embase and Cochrane library with no language or date restriction up to January 1st, 2023, was performed following the PRISMA guidelines. We included retrospective or prospective case-control and cohort studies as well as prospective clinical trials comparing survival outcomes of premenopausal female patients with reported pregnancy or not after diagnosis and treatment for hormone receptor-positive breast cancer. Participants/materials, setting, methods Included patients were childbearing potential age women with a prior history of hormone receptor-positive early breast cancer. Outcomes of interest were disease-free survival and overall survival. Hazard ratios (HR) with 95% confidence intervals (CI) were extracted. Higgins I2 index was used to evaluate the degree of inconsistency in the results of the included studies. Pooled HRs were considered statistically significant with a P value of &amp;lt; 0.05 (two-sided). Main results and the role of chance Eight studies were eligible to be included in the final analysis. A total of 3,805 patients with hormone receptor-positive breast cancer were included in these studies, of whom 1,285 had a pregnancy after treatments. Median follow-up of the included studies ranged from 3.81 years to 15.8 years. In three studies (n = 987 patients) reporting on disease-free survival outcomes, no difference was observed between patients with or without a subsequent pregnancy (HR 0.96, 95% CI 0.75 – 1.24, p = 0.781). Six studies (n = 3,504 patients) reported outcomes in terms of overall survival: patients with a pregnancy after breast cancer had better overall survival compared with those without a pregnancy (HR 0.46, 95% CI 0.27 – 0.77, p &amp;lt; 0.05). At the subgroup analysis on timing of pregnancy, no detrimental effect of pregnancy after breast cancer in terms of disease-free survival was observed for patients achieving a late pregnancy (defined as 2 or 5 years after diagnosis) as compared to patients without a subsequent pregnancy (HR 1.08, 95% CI 0.80 – 1.46, p = 0.611). Increased disease-free survival was observed in patients with an early pregnancy (HR 0.63, 95% CI 0.47 – 0.85, p &amp;lt; 0.05). Limitations, reasons for caution This meta-analysis is based on abstracted data and most of the studies are retrospective cohort studies. Median follow-up in a large proportion of the studies was shorter than 10 years. Adjuvant hormone therapy before and after pregnancy was not available in many studies included. Wider implications of the findings Our results strengthen the evidence that having a pregnancy in women with prior history of hormone receptor-positive breast cancer is safe. Trial registration number not applicable

Impact of HER2 low expression in the Oncotype DX RS in patients with operable hormone receptor positive early stage breast cancer.

575 Background: Two thirds of breast carcinomas are human epidermal growth factor receptor 2 (HER2) low. To date, it is still unclear whether hormone receptor (HR) positive HER2 low tumors represent a distinct biological subtype. HER2 low status is not considered an independent predictive factor for benefit from adjuvant chemotherapy in HR positive early breast cancer. We aim to investigate the impact of HER2 low expression on the established predictive biomarker Oncotype DX RS in a cohort of patients with HR positive HER2 negative early breast cancer. Methods: Retrospective study of patients with stage I-III HR positive HER2 negative breast cancer treated with upfront surgery between 2019-2022 at the Weill Cornell Breast Center and for whom Oncotype DX RS test was available. Patients were grouped to HER2-0 (immunohistochemistry (IHC) score of 0) or HER2 low (IHC score of 1+ or, 2+ with non-amplified in situ hybridization) expression. Clinicopathological characteristics and Oncotype DX RS were compared across the different categories of HER2 expression. Results: Of 509 patients included, 37% and 63% were grouped as HER2-0 and HER2 low, respectively. Median age at diagnosis was 61 years [IQR 50-69]. Sixty-eight percent of patients were postmenopausal. Stage I, II and III corresponded to 76%, 23% and 1% of patients, respectively. Seven percent of patients had nodal involvement. Ductal carcinoma was the most common histological type (75%) followed by lobular carcinoma (17%). Most tumors had low-intermediate histological grade (81%) with a median Ki-67 of 10% [IQR 5-15]. No significant difference was observed in clinicopathological characteristics between the HER2-0 and HER2 low groups. The overall median Oncotype DX RS was 16 [IQR 11-21]. The median Oncotype DX RS based on a HER2 expression of 0, 1+ and 2+ was 15, 17 and 17, respectively. There was no statistically significant difference between the Oncotype DX RS score and HER2 expression, when comparing HER2-0 to HER2 low (p = 0.578), HER2-0 to HER2-1+ (p = 0.775) and HER2-0 to HER2-2+ (p = 0.157). In the pre-menopausal and lobular carcinoma subgroups, the median Oncotype DX RS was 15 [IQR 9-21] and 17 [IQR 12-22], respectively; and there was no statistically significant difference between the Oncotype DX RS score and HER2 expression (p &gt; 0.05). Post-surgery, 87%, 66% and 13% of patients received endocrine therapy, chemotherapy and radiation therapy, respectively. Median follow up time was 16 months [IQR 8-34]. Disease recurrence was documented in 9 (2%) patients. Conclusions: In this study, we found no differences in the Oncotype DX RS and the prognostic pathological features between the HER2-0 and HER2 low groups which is in line with previous retrospective studies. Survival analysis was limited by the median follow up. Further studies on the understanding of the biology of HER2-low and its clinical implications in early breast cancer are needed.

CtDNA mutational profiles in luminal breast cancer with early vs late distant relapse: Geicam/2014-03.

1060 Background: Patients with hormone receptor-positive early breast cancer (BC) can develop resistance to endocrine therapies (ET) and face a continuous risk of relapse, which can occur anywhere from a few months (m) to several decades after surgery. The causes of early vs late relapses are not well understood. Our research examines the presence of oncogenic drivers in circulating tumor DNA (ctDNA) at the time of relapse in patients with luminal BC who have either an early or late distant recurrence. Methods: We identified pts included in the GEICAM/2014-03 study (NCT02819882) with: 1) HR-positive BC, 2) metastatic relapse either &lt;36m (early relapse, [early-R]) or &gt;120m (late relapse, [late-R]) from diagnosis, and 3) ctDNA obtained before first line treatment for advanced disease. The AVENIO ctDNA assay was used for identifying genomic aberrations in 77 cancer-related genes. Results: Eighty-four pts, 36 in early-R and 48 in late-R groups, were selected. Median time to relapse was 24.97m in early-R vs 151.84m in late-R. Median time from last dose of adjuvant ET to relapse was 0.03m for early-R vs 74.06m for late-R. Median PFS to first line treatment was 7.62m in early-R and 35.15m in late-R. With a median follow-up of 32.08m, median OS after diagnosis of metastatic disease was 27.74m for early-R and not reached for late-R. ctDNA analysis detected at least 1 mutation (mut) in 71/84 (85%) pts (89% in early-R vs 81% in late-R). Early-R pts were enriched in mut in TP53 (44% vs 19%), ESR1 (11% vs 4%), MAPK_ERK pathway (14% vs 6%), and ERBB2 copy number alterations (CNA) (25% vs 2%). PI3K/AKT pathway alterations had similar frequency in both recurrence groups (38% vs 42%) and they were not associated with OS. Seven ESR1 mut were detected in 6 pts. In the early-R group there were 5 ESR1 mut (71% of total ESR1 mut), median mutant allele frequency (mMAF): 0.64%; while in the late-R, 2 ESR1 mut (29%), mMAF: 0.4%. ESR1 mut were associated with worse OS (median OS 48.48m vs 12.84m wild-type vs mutant; p=0.0025). There were 10 pts with E RBB2 CNA at metastatic relapse; 9 (25%) in the early-R and 1 pts (2%) in the late-R. Seven pts (70%) had HER2-positive. Pts with ctDNA ERBB2 CNA had worse OS (median OS 48.48m vs 20.52m wild-type vs mutant; p-adj=0.025). Conclusions: In luminal breast cancer (BC), early and late distant relapse differ at both the clinical and genomic levels. Early relapse is a highly aggressive form of the disease and is enriched in TP53 mutations and actionable genetic alterations, such as mutations in the ESR1 and CNA in ERBB2, as detected by ctDNA analysis at the time of metastatic relapse diagnosis. Clinical trial information: NCT02819882 . [Table: see text]

Influence of ovarian function supression on quality of life in breast cancer survivors during adjuvant endocrine therapy.

560 Background: Adding ovarian function suppression to adjuvant endocrine therapy (AET) lowers the disease recurrence rates among premenopausal women with hormone receptor-positive (HR+) early breast cancer (EBC). However, a detrimental effect on endocrine symptoms burden (ESB) is expected. Therefore, this study aimed to investigate differences in Quality of life (QoL) and endocrine symptoms in premenopausal women prescribed AET, with/without gonadotropin-releasing hormone agonist (GnRH). Methods: This cross-sectional study included women, with HR+ EBC, premenopausal at diagnosis, treated with AET for more than 3 months, with and without GnRH. The research was conducted with institutional Ethics Committee approval at the University Hospital Centre Zagreb, General Hospital Šibenik, and with online survey. A validated instrument, the Functional Assessment of Cancer Therapy - Endocrine Symptoms (FACT-ES), was used. The collected data were analysed using SPSS v. 29 (p≤0.05). Results: Overall, 314 eligible BC survivors with a median age of 45 years (22-65) and a median duration of AET of 2 years (3 months -12 years) responded to FACT-ES and were included in the analysis. Altogether 45.2% (n=142) of participants were prescribed tamoxifen (TAM), 25.8% (n=81) GnRH+TAM, and 29% (n=91) GnRH+aromatase inhibitor (AI); exemestane (9%), letrozole (13.6%) and anastrozole (6.4%). The total QoL (FACT-ES) score was higher in patients treated with TAM as opposed to patients treated with AI+GnRH (p=0.01). Adding GnRH to TAM did not significantly change QoL when compared to TAM alone or AI+GnRH. In addition, patients on AI+GnRH had lower physical well-being (PWB) score than patients on TAM+GnRH (p=0.03) or TAM alone (p=0.05) and lower endocrine subscale score (ESS-19) than patients on TAM (p=0.01), indicating more endocrine symptoms in premenopausal women treated with AI+GnRH. Among patients treated with AI+GnRH letrozole had lower PWB (p=0.03) and ESS-19 score (p=0.01) than exemestane. Conclusions: This study showed that GnRH+AI in premenopausal women with HR+ EBC results in greater ESB and lower QoL compared to patients treated with TAM or GnRH+TAM. Therefore, interventions helping decrease the ESB in patients treated with AI+GnRH should be explored and developed to help patients adhere to and persist in AET. [Table: see text]

Clinical Impact of Primary Endocrine Therapy in Hormone Receptor-positive Breast Cancer Patients Unsuited for Radical Treatment

Purpose: Treatment of hormone receptor-positive early breast cancer (HR+EBC) in patients who are unfit for or decline radical treatment requires careful consideration of tumour parameters against functional status, co-morbidities and quality of life. In this retrospective study we reviewed the outcomes of patients treated with primary endocrine therapy (PET) in a single UK centre.

Interrupting Endocrine Therapy to Attempt Pregnancy after Breast Cancer

BackgroundProspective data on the risk of recurrence among women with hormone receptor–positive early breast cancer who temporarily discontinue endocrine therapy to attempt pregnancy are lacking.MethodsWe conducted a single-group trial in which we evaluated the temporary interruption of adjuvant endocrine therapy to attempt pregnancy in young women with previous breast cancer. Eligible women were 42 years of age or younger; had had stage I, II, or III disease; had received adjuvant endocrine therapy for 18 to 30 months; and desired pregnancy. The primary end point was the number of breast cancer events (defined as local, regional, or distant recurrence of invasive breast cancer or new contralateral invasive breast cancer) during follow-up. The primary analysis was planned to be performed after 1600 patient-years of follow-up. The prespecified safety threshold was the occurrence of 46 breast cancer events during this period. Breast cancer outcomes in this treatment-interruption group were compared with those in an external control cohort consisting of women who would have met the entry criteria for the current trial.ResultsAmong 516 women, the median age was 37 years, the median time from breast cancer diagnosis to enrollment was 29 months, and 93.4% had stage I or II disease. Among 497 women who were followed for pregnancy status, 368 (74.0%) had at least one pregnancy and 317 (63.8%) had at least one live birth. In total, 365 babies were born. At 1638 patient-years of follow-up (median follow-up, 41 months), 44 patients had a breast cancer event, a result that did not exceed the safety threshold. The 3-year incidence of breast cancer events was 8.9% (95% confidence interval [CI], 6.3 to 11.6) in the treatment-interruption group and 9.2% (95% CI, 7.6 to 10.8) in the control cohort.ConclusionsAmong select women with previous hormone receptor–positive early breast cancer, temporary interruption of endocrine therapy to attempt pregnancy did not confer a greater short-term risk of breast cancer events, including distant recurrence, than that in the external control cohort. Further follow-up is critical to inform longer-term safety. (Funded by ETOP IBCSG Partners Foundation and others; POSITIVE ClinicalTrials.gov number, NCT02308085.)

114P Retrospective analysis to validate the CTS5 in patients from El Álamo IV registry and GEICAM adjuvant studies

Estimating the risk of late distant recurrence (DR) is an important goal for the management of hormone receptor-positive (HR+) early breast cancer (EBC) patients (pts) after 5 years of endocrine treatment (ET) without recurrence. The Clinical Treatment Score post–5 years (CTS5) tool was developed to estimate residual risk of Distant Recurrence (DR) after 5 years of ET (Dowsett 2018). CTS5 is a continuous score based on 4 clinical variables (number of positive nodes, tumor size, grade, and age) which distributes HR+/human epidermal growth factor receptor-negative (HER2-) EBC pts in 3 risk of DR groups depending on the score (low-risk: <3.13, intermediate-risk: 3.13-3.86 and high-risk: > 3.86). We performed a retrospective analysis of 5739 HR+/HER2- EBC pts to validate the CTS5 score as prognostic tool of late relapse, beyond 5 years. They were selected from El Álamo IV registry with pts diagnosed between 2002 and 2005 (N=3061) and 4 adjuvant GEICAM studies (9805, 9906, 2003-02 and 2003-10; N=2678) carried out from 1996 and 2006. Pts had to be distant recurrence free at 5 years from ET initiation. CTS5 classified 43.9% as low-risk, 32.2% as intermediate-risk and 23.9% as high-risk. A significant difference in DR was seen among the three groups, HR intermediate-risk vs low, 2.55 (95% CI, 1.85 to 3.52) and HR high-risk vs low, 5.77 (95% CI, 4.28 to 7.78). The continuous CTS5 (range: 1.2 - 6.06) was significantly prognostic (HR, 2.31; 95% CI, 2.05 to 2.61). DR percentage expected and observed by subgroups are described in the table. The CTS5 was able to classify Spanish patients according to different risk of late DR, independently of menopausal status, ET duration or CT treatment. However, the model seems to overestimate the number of events particularly in the high-risk group. This overestimation was more pronounced among patients treated with ET for less than 60 months or those not receiving CT.

155TiP A randomised phase II trial of neoadjuvant multi-agent chemotherapy (CHT) OR patritumab deruxtecan (HER3-DXd; U3-1402) +/- endocrine therapy (ET) for high-risk hormone receptor-positive (HR+/HER2-) early breast cancer (EBC): SOLTI-2103 VALENTINE trial

The decision of neoadjuvant treatment for high-risk HR+/HER2- EBC remains a challenge. Despite the availability of both CHT and ET, the risk of recurrence persists over time, highlighting the need for additional therapeutic strategies. In the TOT-HER3 trial, we have shown that a single dose of HER3-DXd, a first-in-class HER3 directed antibody drug conjugate, is associated with clinical response, increased immune infiltration and proliferation suppression, as well as a consistent and manageable safety profile in patients (pts) with HR+/HER2-negative early breast cancer (Prat et al. ESMO Breast 2022). These data have informed the design of the VALENTINE trial of HER3-DXd in the neoadjuvant setting. VALENTINE is a parallel, exploratory, three-arm, randomised, open-label, exploratory study in pts with primary operable HR+/HER2-negative breast cancer with Ki67 IHC ≥ 20% and/or high genomic risk (defined by gene signature), aiming to evaluate the clinical benefit and biological effects of HER3-DXd (with/without letrozole (LET)) as a neoadjuvant treatment. A total of 120 treatment naïve pts will be randomly assigned in a 2:2:1 ratio to receive (1) HER3-DXd (5.6 mg/kg) every 21 days for 6 cycles; (2) HER3-DXd plus daily LET +/- LHRH analogs every 21 days for 6 cycles; (3) standard of care CHT consisting of 4 cycles of EC/AC (epirubicin 90 mg/m2 or doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 14/21 days) followed by weekly 80mg/m2 paclitaxel during 12 weeks. The primary endpoint is the rate of pathological complete response (ypT0/is ypN0) at surgery. Baseline, on-treatment (C2D1), and surgical specimens will be collected for molecular characterization and evaluation of response (ERBB3 gene expression, HER3 IHC; CelTIL change, research-based PAM50 subtypes). Additional samples for pharmacokinetic, genomic and circulating biomarkers will also be collected. Secondary endpoints include rate of residual cancer burden, overall response rate, invasive disease-free survival at 3 and 5 years and safety. An interim and final analysis are pre-planned. EudraCT 2022-001181-36. NCT05569811, First Posted: February 18, 2021. SOLTI Cancer Research Group.

Adherence to adjuvant tamoxifen and associated factors in breast cancer survivors

Adjuvant endocrine therapy reduces the recurrence and mortality of early hormone receptor-positive breast cancer in both pre- and postmenopausal women. The aim of this study was to investigate adjuvant tamoxifen adherence and associated factors in breast cancer survivors. This descriptive, prospective study was conducted in 2019-2020 with the participation of 531 women who survived breast cancer and were under follow-up at the Senology Institute of a hospital in Istanbul. Inclusion criteria were having completed treatment for early hormone receptor-positive breast cancer, being prescribed tamoxifen, and being 18years or older. Data were collected using a patient information form and the Morisky Medication Adherence Scale-8 (MMAS-8). The mean age of the participants was 44.9 ± 6.5years, and the mean duration of tamoxifen use was 834.4 ± 685.7days. The women's mean MMAS-8 score was 6.86 ± 1.39. Medication adherence was significantly positively correlated with current age (p = 0.006) and age at diagnosis (p = 0.002). There was a statistically significant difference between tamoxifen adherence according to participants' employment status (p = 0.028), chronic disease status (p = 0.018), loss of libido (p = 0.012), treatment-related changes in mood changes (p = 0.004), and having negative effects affecting daily life (p < 0.001). Overall, breast cancer survivors in this study reported moderate adherence to tamoxifen. The women's individual characteristics and the adverse effects of treatment influenced medication adherence. Healthcare professionals can help increase adherence to this treatment, which reduces the risk of mortality, by explaining the importance of the medication, identifying and eliminating barriers to adherence, and informing women about evidence-based interventions to increase medication compliance.

Abstract OT1-04-01: AMEERA-6: Phase 3 Study of Adjuvant Amcenestrant Versus Tamoxifen for Patients With Hormone Receptor-Positive Early Breast Cancer, Who Have Discontinued Adjuvant Aromatase Inhibitor Therapy Due to Treatment-related Toxicity

Abstract Background: About 30% of patients (pts) with hormone receptor (HR)-positive early breast cancer (EBC) on adjuvant aromatase inhibitor (AI) therapy discontinue due to toxicity with 22% of pts discontinuing during the first year (Henry et al. JCO 2012). For these patients who struggle with adjuvant AIs, there are limited alternatives including switch to a different AI which may have similar side effects, tamoxifen, or observation. This paucity of effective and tolerable options may contribute to poor adherence and/or early discontinuation of adjuvant endocrine therapy, which is associated with worse outcomes. Amcenestrant (SAR439859) is an optimized oral selective estrogen receptor degrader (SERD) with potent dual activity which antagonizes and degrades the estrogen receptor (ER), resulting in inhibition of the ER signaling pathway. In the phase 1/2 AMEERA-1 first-in-human trial (SABCS 2020 PD8-08), amcenestrant showed strong antitumor activity and favorable safety profile in the treatment of HR+ metastatic breast cancer. The phase 2 window-of-opportunity study AMEERA-4 evaluating two doses of amcenestrant demonstrated robust Ki67 reductions, strong engagement of the ER target, and continued to show a favorable safety profile in an early breast cancer population. Based on pharmacodynamic activity, safety, and emerging results from other ongoing amcenestrant trials, the 200 mg daily dose of amcenestrant was selected for the AMEERA-6 study. Trial Design: This is a prospective, randomized, international, double-blind, double-dummy, phase 3 superiority study of amcenestrant versus tamoxifen. Eligible pts are men and women with any menopausal status with HR+ stage IIB/III breast cancer, irrespective of human epidermal growth factor receptor 2 (HER2) status. If neoadjuvant systemic therapy was administered, pts must have residual nodal disease after definitive breast surgery (ypN1-3). Pts will be centrally assessed to have ER-positive and/or progesterone receptor-positive (≥10% positive stained cells) status by immunohistochemistry assay. Pts must have received at least 6 months of adjuvant AIs (≥3 months in the adjuvant setting if they received prior neoadjuvant AI) and discontinued within 30 months of initiation due to AI-related toxicity. Pts may have been treated with more than one AI. All adjuvant therapies including chemotherapy, anti-HER2 treatment, cyclin-dependent kinase (CDK) 4/6 inhibitor, and/or poly (ADP-ribose) polymerase (PARP) inhibitors must be completed or stopped prior to randomization. 3738 pts will be randomized 1:1 to receive either amcenestrant 200 mg daily or tamoxifen 20 mg daily for 5 years and will be followed for 10 years from randomization. Men and pre/peri-menopausal women will also receive a GnRH analog. Extended adjuvant endocrine therapy upon completion of study treatment is allowed per investigator discretion. Stratification factors include duration of prior AI therapy, HER2 status and prior chemotherapy, prior CDK4/6 inhibitors, geographic region, and menopausal status. The primary endpoint is invasive breast cancer-free survival (IBCFS) based on STEEP criteria version 2.0 defined as occurrence of first recurrence of the disease: ipsilateral or regional invasive, distant recurrence, contralateral invasive breast cancer and death. Key secondary endpoint is invasive disease-free survival (IDFS) and other secondary endpoints include overall survival, safety, patient reported outcomes, and pharmacokinetics of amcenestrant. Adherence to treatment and biomarkers are exploratory endpoints. AMEERA-6 recruited the first patient in March 2022 and is being conducted in partnership with AFT, BIG, EORTC, and Sanofi. Clinical trial information: NCT05128773 Citation Format: Otto Metzger, Christina Herold, Coralie Poncet, Heidi De Swert, Jose Casas-Martin, Ann Partridge, Samia Guita, Lisa Carey, Eva Schumacher, Theodora Goulioti, Thomas Meyskens, Joseph Gannon, Khadija Benlhassan, Giovanna Rossi, Eleni Xenophontos, Amal Arahmani, Amylou C. Dueck, Gautier Paux, Etienne Brain, David A. Cameron. AMEERA-6: Phase 3 Study of Adjuvant Amcenestrant Versus Tamoxifen for Patients With Hormone Receptor-Positive Early Breast Cancer, Who Have Discontinued Adjuvant Aromatase Inhibitor Therapy Due to Treatment-related Toxicity [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-04-01.

Abstract P5-09-05: A phase II, single-arm study of histone deacetylases inhibitor Tucidinostat and Exemestane as neoadjuvant therapy in patients with hormone receptor positive HER2 negative breast cancer (NeoTEE trial)

Abstract Background: Tucidinostat (formerly known as chidamide) plus exemestane is approved for postmenopausal patients with advanced, hormone receptor-positive breast cancer. We evaluated the efficacy and safety of tucidinostat plus exemestane as the neoadjuvant strategy in hormone receptor-positive early breast cancer patients. Methods: NeoTEE is an open-label, single-center, phase II study. Patients with HR-positive, HER2-negative and stage II/III breast cancer were enrolled at the First Affiliated Hospital of Sun Yat-sen University. Eligible patients received 25 mg oral exemestane once daily for 2 weeks followed by 30 mg oral tucidinostat twice weekly in combination with 25mg oral exemestane once daily for 24 weeks. GnRHa was used for premenopausal patients. Endpoints assessed here included objective response rate (ORR), complete cell cycle arrest (CCCA, Ki-67≤2.7%) at surgery, disease control rate (DCR), pathological complete remission (pCR) and safety. Results: Between July 2020 and July 2022, 26 patients were enrolled, of whom 24 were evaluable for response per RECIST 1.1 criteria. Partial response (PR) was observed in 18 patients, with an ORR of 75% (18/24). The DCR was 100%. Of the 14 patients with surgery, one patient achieved pCR and 8 patients were exempt from postoperative adjuvant chemotherapy. CCCA at surgery was 64.3% (9/14). The follow-up remains ongoing and updated results will be presented thereafter. Most adverse events (AEs) were grade 1 or 2. Grade 3 AEs occurred in 8 of 26 patients, the most common were neutropenia 19.2%, leukopenia 7.7%, anemia 3.8%, ALT increased 3.8%, pneumonitis 3.8%. Only 1 patient experienced grade 4 neutropenia. Grade 3/4 neutropenia recovered after dose reduction or discontinuation of tucidinostat. No patient received G-CSF. Conclusions: Tucidinostat combined with exemestane was well tolerated and demonstrated meaningful responses in neoadjuvant setting for women with early HR+/HER2- breast cancer. Further investigation is warranted. Clinical trial information: NCT04465097. Citation Format: zhen shan, nan shao, xiaoling zhang, huijuan shi, yanling zheng, jia luo, tiantian zhen, ruping chen, Ying Lin. A phase II, single-arm study of histone deacetylases inhibitor Tucidinostat and Exemestane as neoadjuvant therapy in patients with hormone receptor positive HER2 negative breast cancer (NeoTEE trial) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-09-05.