Early Stage HR Research Articles

Neoadjuvant sunitinib plus exemestane in post-menopausal women with hormone receptor-positive/HER2-negative early-stage breast cancer (SUT_EXE-08): a phase I/II trial

Neoadjuvant endocrine therapy (NET) for hormone receptor-positive (HR+) breast cancer might be as effective as chemotherapy, with a better toxicity profile. Blocking a crucial process such as angiogenesis with sunitinib may have a synergistic effect with NET. We aimed to assess the efficacy and safety of neoadjuvant sunitinib plus exemestane in early-stage HR+/HER2-negative breast cancer. In this phase I/II study, postmenopausal women with HR+/HER2− stage II-III breast cancer received neoadjuvant exemestane at conventional dose of 25mg plus sunitinib in a 3 + 3 design at 25mg (3/1weeks scheme) or 37.5mg continuous dose, for 6 months. Coprimary endpoints were the recommended dose of sunitinib combined with exemestane and objective response. Secondary endpoints included safety and biomarkers of early response. For 15 months, 18 patients were enrolled, 15 at sunitinib 25mg and 3 at 37.5mg. Median age was 73, 77% of patients had T2 tumors and 67% node-positive disease. The most common grade 2 toxicity was asthenia (44%), as was hypertension (22%) for grade 3. No grade 4–5 were reported. Twelve patients (66%) achieved an objective response. VEGFR-2 levels significantly decreased after one month of treatment. Differential gene expression analysis showed downregulation of ESR1, PGR and NAT1 in post-treatment samples and upregulation of EGFR, MYC, SFRP1, and FOXC1. PAM50 analysis on 83% of patients showed a prevalence of luminal A subtype, both in pre-treatment (63.6%) and post-treatment tumors (54.5%). Sunitinib plus exemestane was associated with substantial yet reversible toxicities, providing safety, efficacy and biological impact insights of combining an antiangiogenic drug with hormone therapy in early-stage breast cancer.Trial registration: Registered with ClinicalTrials.gov, NCT00931450. 02/07/2009

Monitoring of estradiol levels in premenopausal women receiving adjuvant abemaciclib and ovarian function suppression.

Approximately 15% of women who receive ovarian function suppression (OFS) as adjuvant treatment for high-risk, localized hormone receptor-positive (HR+) breast cancer may have inadequate estradiol suppression which can require therapeutic modification when used in combination with an aromatase inhibitor (AI). We previously reported that abemaciclib may interfere with the estradiol Abbott Alinity chemiluminescent microparticle immunoassay (CMIA) commonly used to monitor estradiol levels and suggested liquid chromatography-mass spectrometry (LC-MS/MS) is preferred in this setting. The aim of this study was to determine discrepancies in estradiol levels using CMIA compared to LC-MS/MS and subsequent treatment changes in a larger patient population. We conducted a retrospective review of premenopausal women with early-stage HR+ breast cancer at our institution who received adjuvant OFS and abemaciclib with at least 1 CMIA estradiol level drawn during abemaciclib therapy from October 2021 to April 2023. Of the 22 women who met criteria for review, 20 (90.9%) had CMIA estradiol levels in the premenopausal range, of whom 9 also had estradiol measured by LC-MS/MS. All 9 women receiving OFS and abemaciclib with estradiol measurements by both methods had premenopausal range CMIA estradiol levels and postmenopausal range LC-MS/MS estradiol levels. Of the 20 patients with premenopausal estradiol levels by CMIA estradiol, treatment changes included increased OFS dosage or preparation (n = 7), change from AI to tamoxifen (n = 3), and surgical oophorectomy (n = 7). Our findings suggest the likely interference of abemaciclib with the Abbott Alinity immunoassay which may lead to unnecessary treatment changes. It is recommended that the LC-MS/MS assay be used when monitoring estradiol levels in patients receiving abemaciclib concurrently with OFS.

Nodal Surgery for Patients ≥ 70 Undergoing Mastectomy for DCIS? Choose Wisely.

Routine sentinel lymphadenectomy (SLNB) for early-stage HR+/HER2- breast cancer in women ≥70 is discouraged by Choosing Wisely, but whether SLNB can be routinely omitted in women ≥70 with DCIS undergoing mastectomy is unclear. This study aims to evaluate rates of axillary surgery and nodal positivity (pN+) in this population to determine the impact of axillary surgery on treatment decisions. Females ≥70 with DCIS undergoing mastectomy were identified from the National Cancer Database (2012-2020). The rate of upstaging to invasive cancer (≥pT1) or pN+ was assessed. Subset analyses were conducted for ER+ patients. Adjuvant therapies were evaluated among ≥pT1 patients after stratifying by nodal status. Of 9,030 patients, 1,896 (21%) upstaged to ≥pT1. Axillary surgery was performed in 86% of patients, predominantly sentinel lymphadenectomy (SLNB, 65%). Post hoc application of Choosing Wisely criteria demonstrated that 93% of the entire cohort and 97% of ER+ DCIS patients could have avoided axillary surgery. Nodal positivity was 0.3% among those who didn't upstage, and 12% among those upstaging to ≥pT1, with <2% having pN2-3 disease, irrespective of receptor subtype. Node-positive patients had higher adjuvant therapy usage, but there was no recommendation for adjuvant chemotherapy or radiation for 71% and 66% of pN+ patients, respectively. Axillary surgery can be omitted for most patients ≥70 undergoing mastectomy for ER+ DCIS, aligning with recommendations for invasive cancer, and omission can be considered in those with ER- disease. Future guidelines incorporating preoperative imaging, as in the SOUND trial, may aid in identifying patients benefiting from axillary surgery.

Controversies on chemotherapy for early HR+/HER2- breast cancer: the role of anthracyclines and dose intensification.

Use of adjuvant chemotherapy significantly reduces the risk of recurrence and improves overall survival (OS) in patients with early-stage breast cancer. However, few data are available on the efficacy of different adjuvant chemotherapy regimens and schedules in patients with hormone receptor positive/HER2-negative (HR+/HER2-) breast cancer. We aim to summarize the available evidence on the efficacy of adjuvant anthracycline-based chemotherapy and of the dose-dense schedule in this specific patient population. Moreover, current controversies in the management of patients with early-stage HR+/HER2- breast cancer are discussed. Patient-level meta-analysis evaluating the role of the addition of an anthracycline to taxane-based chemotherapy showed that recurrence rate was lower among patients receiving anthracycline-based treatment.Patient-level meta-analysis evaluating the role of different schedules of chemotherapy administration showed that the use of adjuvant dose-dense chemotherapy is associated with significant reduction in breast cancer recurrences and breast cancer mortality. Less evidence is available in the neoadjuvant setting. For patients with high-risk HR+/HER2- breast cancer, (neo) adjuvant anthracycline and taxane-based chemotherapy, and a dose-dense regimen should still be considered the standard of care. However, in patients with intermediate risk breast cancer candidates to chemotherapy, anthracycline-free regimens could be considered the preferred treatment option.

Examining a genomic test in predicting extended endocrine benefit and recurrence risk in a diverse breast cancer population.

e12526 Background: Extending adjuvant endocrine therapy (EET) beyond five years for early-stage hormone receptor-positive (HR+) breast cancer reduces late distant recurrence risk. The genomic test, Breast Cancer Index (BCI), has prognostic value and predicts the benefits of prolonged therapy, yet no studies have explored this testing in a diverse population. This study assesses late distant recurrence risk and predictive benefits of EET to better understand its relevance in a diverse early-stage HR+ breast cancer population. Methods: We analyzed patient demographics, clinical and pathologic characteristics, and BCI scores of 150 women in Hawaii with early-stage HR+ breast cancer, self-identifying as White, Filipino, Japanese, Native Hawaiian, or other. Tumor characteristics examined include size, grade, histology, lymph node, and ER/PR/HER2 receptor status. Logistic regression analyses used race, distant recurrence risk, and tumor features as predictor variables. BCI prediction of benefit and distant recurrence risk served as outcome variables. Results: Japanese patients had significantly lower odds of having a high risk for distant recurrence (OR = 0.02, p &lt; 0.0001) compared to White. Other Asian PIs also showed reduced odds of high distant recurrence risk (OR = 0.07, p = 0.02), albeit to a lesser extent than Japanese. Patients with high distant recurrence risk had significantly greater odds of a score predicting benefit than those with low risk (OR = 5.03, p = 0.009). Racial or ethnic differences in predicting benefit with EET were not statistically significant. Conclusions: Results show no racial or ethnic differences in predicting the benefit of EET, strengthening BCI’s universal applicability in diverse women with early-stage HR+ breast cancer. Patients with higher distant recurrence risk were predicted to benefit from EET. This suggests potential variations in tumor features or other factors affecting distant recurrence risk among racial groups. Limitations include a relatively small sample size and lack of data from patients representing other racial groups. Future studies should expand the sample size and adjust for known breast cancer risk factors to better understand the racial and ethnic implications of BCI.

EE43 Understanding the Humanistic and Economic Burden Associated with Early-Stage HR+/HER2- Breast Cancer: A Systematic Literature Review

EE43 Understanding the Humanistic and Economic Burden Associated with Early-Stage HR+/HER2- Breast Cancer: A Systematic Literature Review

Evaluation of recurrence rate in Canadian patients with stage II/III HR+/HER2- early breast cancer in the real-world setting.

e23303 Background: Breast cancer is the most prevalent cancer and second leading cause of cancer-related mortality among Canadian women. Most of cases belong to the HR+/HER2- subtype, representing approximately two-thirds of all instances. Treatment for this subtype encompasses a multifaceted approach with a curative intent. This real-world evidence study aims to comprehensively analyze the clinical outcomes of Canadian patients diagnosed with early-stage HR+/HER2- breast cancer, focusing on recurrence rates after initiation of adjuvant endocrine therapy to identify opportunities for enhancing patient care. Methods: This is a retrospective, longitudinal cohort study involving 541 patients enrolled in the pan-Canadian cancer patient registry PMT (Personalize My Treatment), with newly diagnosed or recurrent stage II or III HR+/HER2- breast cancer between January 1st, 1996, and May 31st, 2022. We evaluated disease recurrence rates, time to recurrence, and overall survival (OS). Furthermore, the study explored duration of endocrine therapy (ET) in the adjuvant setting. Results: 409 patients received adjuvant ET representing 75.6% of the total cohort, emphasizing the role of ET as standard of care for adjuvant treatment in this patient population. The median duration of adjuvant ET was 4.5 years. In the overall adjuvant patient population, recurrence rates progressively increased over time from 13.2% after 2 years, 21.4% after 3 years, 30.3% after 5 years, and peaking at 58.4% after 10 years. Median time to recurrence for the overall patient population on ET was 7.76 years. OS rate for patients on ET was 94.6% at 5 years and 78.3% at 10 years. Conclusions: This study marks a pioneering real-world analysis utilizing pan-Canadian EHR data, demonstrating increasing recurrence rates over time in HR+/HER2- early breast cancer. It highlights the high unmet need in stage II and stage III breast cancer, with 1 patient out of 3 recurring after 5 years, and more than half recurring after 10 years despites adjuvant treatment with ET alone. This indicates the need for more efficacious and tolerable treatment options to reduce short- and long-term recurrence and to prolong survival, not only in the higher risk patient population, but in the overall HR+/HER2- breast cancer patients at increased risk of recurrence.

Breast Cancer Index re-stratifies 21-gene assay risk groups for late distant recurrence and extended endocrine therapy benefit: Results from the BCI Registry Study.

529 Background: Patients with hormone receptor-positive (HR+) breast cancer face a prolonged risk for late distant recurrence (DR), even after 5 years of adjuvant endocrine therapy. The BCI (Breast Cancer Index, Biotheranostics) is a genomic assay that provides the risk of late DR and predicts the likelihood of benefit from extended endocrine therapy (EET) based on the H/I (HOXB13/IL-17BR) ratio. The 21-gene RS (Recurrence Score; Oncotype DX, Exact Biosciences) test provides the 9-year risk of DR and the benefit from adjuvant chemotherapy (CT) in HR+/HER2− breast cancer. However, the RxPONDER trial showed that RS was not predictive of CT benefit in premenopausal women with N1 disease. Here, we investigated the concordance between BCI prognostic score and H/I versus RS in HR+/HER2- patients from the BCI Registry study. Methods: The BCI Registry study is a prospective, multi-institutional study to evaluate the long-term clinical outcome, decision impact and medication adherence in early-stage HR+ breast cancer patients. Based on TAILORx and RxPONDER results, RS stratified patients into four risk groups: Age ≤ 50, No CT benefit (RS ≤ 15); Age ≤ 50, CT benefit (RS&gt;15); Age &gt; 50, No CT benefit (RS ≤ 25); and Age &gt; 50, CT benefit (RS &gt; 25). Kendall’s correlation coefficient (R) was used to estimate the correlation between BCI prognostic score, BCI (H/I) and RS as continuous variables. Results: BCI and RS results were reported for 847 patients (76% T1; 59% grade II; 85% N0). H/I classified 559 patients (66%) as H/I-Low and 288 (34%) as H/I-High, respectively, while BCI prognostic risk scores classified 434 patients (51%) as low-risk and 413 (49%) as high-risk for late DR. RS classified 30 patients (4%) as Age ≤ 50, No CT benefit, 38 (5%) as Age ≤ 50, CT benefit, 665 (78%) as Age &gt; 50, No CT benefit and 114 (13%) as Age &gt; 50, CT benefit. When analyzed as continuous variables, BCI H/I and prognostic score showed a weak correlation with RS with R=0.18 and R=0.2, respectively. Based on categorical groups, H/I had low concordance with RS for younger women (Age ≤ 50) but showed some correlation with RS for older women (Age &gt; 50). Among those older than Age 50, H/I identified 31% of those with no CT benefit as likely to benefit from EET while 39% of those with CT benefit as not likely to benefit from EET. Conclusions: BCI H/I and prognostic risk scores exhibited low concordance with RS risk categories. H/I consistently re-stratified RS risk categories into distinct H/I-Low and -High groups, further substantiating that prediction of CT benefit does not equate to prediction of EET benefit. [Table: see text]

Assessing the feasibility and cost-effectiveness of all oral adjuvant chemotherapy (cyclophosphamide, methotrexate, capecitabine) in high-risk hormone receptor positive breast cancer.

TPS616 Background: Women with high-risk HR+/HER2- breast cancer (BCA) receive additional chemotherapy to reduce disease recurrence. Preferred Taxane and Anthracycline based chemotherapy regimens have debilitating side effects such as cardiotoxicity, leukemia, peripheral neuropathy, severe fatigue, alopecia, downtime which are more common in black women thereby necessitating dose reductions. Metronomic cyclophosphamide, methotrexate, 5-fluourouracil (CMF) is an option but less preferred due to frequent dosing and longer therapy duration. Head-to-head comparison of CMF to anthracycline-based chemotherapy conducted 3 decades ago in early-stage BCA showed anthracycline benefit was driven by HER2+ disease with no benefit for HR+/HER2- BCA. Head-to-head comparison trials of CMF and Taxane-based regimen have not been conducted but single institution data suggest similar disease-free and similar overall survival but different toxicity profiles favoring CMF. In our ongoing trial, we converted all three chemotherapy drugs in CMF regimen to an all-oral regimen namely oral Cyclophosphamide, oral Methotrexate, oral Capecitabine (CMC) with the potential benefit of increased patient convenience, decreased costs (oral agents are generic; no chair time; no growth factors), and improved toxicity profile (low rates of grade III neutropenia, no port complications, no alopecia). This trial in progress aims to evaluate the feasibility of oral CMC by measuring the relative dose intensity in addition to the safety and tolerability of oral CMC. We hypothesize that 80% of patients will receive &gt;85% of the intended dose of oral CMC. Methods: This is a Phase II, single arm, non-randomized study enrolling 25 patients with high-risk early-stage HR+ HER2- breast cancer to receive oral CMC regimen based on dose conversion equivalent bioavailability with conventional metronomic CMF chemotherapy. Enrolled patients will receive adjuvant therapy of oral cyclophosphamide 60 mg/m2 PO days 1-21 continuously, Methotrexate 15 mg/m2 PO Day 1, 8, and 15 and Capecitabine 650 mg/m2 PO BID Day 1- 14 to be given every 21 days for 8 cycles. The primary objective is to assess feasibility which is defined as 80% of patients (greater than 20 patients) maintaining a relative dose intensity (RDI) &gt; 85%. The RDI is calculated as the ratio of the actual dose intensity/standard dose intensity; the average RDI for oral CMC regimen is the sum of RDI for each drug divided by 3. This study will be stopped if &gt;25% of patients report Grade 4+ toxicity on oral CMC. The secondary objectives will assess quality of life as reported by the patients and report adverse effects. Clinical trial information: NCT06085742 . [Table: see text]

Abstract PO3-01-09: Results of a prospective observational study evaluating the impact of the Prosigna assay on neoadjuvant treatment decision-making in patients with early-stage HR+/HER2- breast cancer

Abstract Background. Prosigna (PAM50) is an FDA-approved prognostic test that measures the expression of 50 classifier genes in breast cancer tissue samples. It provides intrinsic subtyping, which classifies the biology of an individual patient's tumor, as well as a risk of recurrence (ROR) score that predicts the probability of distant recurrence over 10 years. Currently, the Prosigna assay is only approved for use in postoperative specimens. Given studies demonstrating that Prosigna can identify tumors that are more likely to benefit from chemotherapy, this decision-impact study sought to evaluate whether the assay could influence physicians' choices and patients' confidence in the neoadjuvant treatment plan. Methods. This prospective observational study was conducted at a single institution and included patients with HR+/HER2- breast cancer measuring ≥ 0.5 cm, any nodal status, who were deemed candidates for neoadjuvant systemic treatment based on physician’s choice. Formalin-fixed paraffin-embedded core biopsy specimens were centrally analyzed using Prosigna. Patients' tumors were classified according to intrinsic tumor subtype (Luminal A, Luminal B, HER2-enriched, Basal-like) and ROR score (low, intermediate, or high). Physicians and patients were surveyed before and after performing Prosigna, regarding neoadjuvant therapy recommendations. The primary endpoint was assessment of the effect of Prosigna on oncologists' treatment recommendations and the actual treatment received (neoadjuvant hormonal therapy [NAHT], neoadjuvant chemotherapy [NACT], or upfront surgery). Secondary endpoints included determining whether treatment changes were based on ROR score, intrinsic subtype, or both, as well as assessing physicians' and patients' confidence in the treatment plan. Results. A total of 54 patients were enrolled in the study between March 2019 and April 2023. The distribution of intrinsic tumor subtypes was as follows: 15 patients (28%) had a Luminal A subtype, 34 (63%) had a Luminal B subtype, 3 (6%) had a HER2-enriched subtype, and 2 (4%) had a Basal-like subtype. Thirty-three patients (61%) were classified as ROR-low, 11 (20%) as ROR-intermediate, and 10 (19%) as ROR-high. Out of the 43 patients who had both pre- and post-assay survey results available, a change in the treatment decision was observed in 28% of cases. Specifically, 14% of patients transitioned from NAHT to NACT, 7% from NACT to NAHT, and 5% from NACT to upfront surgery, as shown in the Table. Treatment changes were based on the ROR score, intrinsic subtype, and both in 33%, 3%, and 64% of cases, respectively. Overall, 45% of physicians experienced an increase in confidence for the treatment plan after Prosigna testing, while 16% reported a decrease and 39% maintained the same level of confidence. Sixty-two percent of patients experienced a reduction in anxiety about treatment. Associations of ROR score and intrinsic subtypes will be presented at the meeting. Conclusion. Prosigna performed on presurgical core biopsies influenced oncologists' treatment recommendations regarding neoadjuvant treatment and reduced patient anxiety about treatment among patients with early-stage HR+/HER2- breast cancer. Table. Neoadjuvant treatment recommendations before and after Prosigna assay, overall and according to nodal status. Data are presented as frequencies (%). Abbreviations: NACT, neoadjuvant chemotherapy; NAHT, neoadjuvant hormonal therapy. Citation Format: Chiara Corti, Xiangying Chu, Pedro Exman, Danielle Kline, Nolan Priedigkeit, Nabihah Tayob, Erica Mayer, Adrienne Waks, Melissa Hughes, Antonio Giordano, Giuseppe Curigliano, Nancy Lin, Tari King, Rinath Jeselsohn, Deborah Dillon, Elizabeth Mittendorf, Sara Tolaney. Results of a prospective observational study evaluating the impact of the Prosigna assay on neoadjuvant treatment decision-making in patients with early-stage HR+/HER2- breast cancer [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 PO3-01-09.

Abstract PO4-02-03: Distribution of MammaPrint, BluePrint, and Response Predictive Subtypes based on ImPrint and Reprint in ER+/HER2- Invasive Lobular Carcinoma – A FLEX sub study

Abstract Background: Invasive lobular carcinoma (ILC), the second most common histologic subtype of breast cancer, is increasingly recognized as a distinct tumor type compared to the more common invasive ductal carcinoma (IDC). While ILC is known to have lower rates of pathologic complete response to neoadjuvant chemotherapy, ILC tumors are biologically heterogenous. As such, genomic signatures might identify patients with ILC who might benefit from tailored treatment options. The gene expression signature MammaPrint (MP) classifies tumors as having a Low Risk or High Risk of distant recurrence. MP combined with BluePrint (BP), a molecular subtyping signature, categorizes tumors as Luminal A (MP Low Risk), Luminal B (MP High Risk), Basal or HER-2 type. ImPrint is a 53-gene signature that identifies HR+HER2- patients predicted to benefit from immune checkpoint inhibitors. RePrint is a 60-gene DNA repair deficiency (DRD) signature that identifies HR+HER2- patients who may benefit from PARP inhibitors with platinum agents. Response Predictive Subtypes (RPS), used in the I-SPY2 trial, combine clinical subtype and these genomic signatures to personalize treatment planning and improve outcomes. In this study, we determined the distribution of 3 RPS in HR+HER2-: (1) ImPrint-/RePrint-, (2) ImPrint-/RePrint+ (3) ImPrint+, in patients ILC compared to IDC enrolled in the FLEX trial. Methods: This study includes 1078 HR+HER2-women with ILC and 6078 with IDC enrolled in FLEX registry. FLEX (NCT03053193) is a prospective, observational trial that includes stage I-III breast cancer patients who undergo MammaPrint testing (with or without BluePrint) as standard of care, and consent to full transcriptome and clinical data collection. MP High Risk tumors were further stratified into High 1 and High 2. ImPrint and Reprint results were used to determine RPS. A two-tailed proportional z-test was used to assess differences between ILC and IDC as well as between RPS. Results: ILC patients had a significantly lower percentage of MP High Risk tumors in comparison to IDC. Among MP High Risk tumors, those with ILC had significantly more MP High 1 than patients with IDC. BP subtyping in ILC tumors showed significantly lower percentage of Basal, and Luminal B, and higher percentage of Luminal A compared to IDC tumors. For RPS, a higher percentage of ILC tumors were ImPrint-/RePrint- compared to IDC, whereas lower frequencies of ImPrint-/RePrint+ and ImPrint+ were found. Within the ILC ImPrint+ subgroup (n=14), 1 (7.1%) was classified as High 2 and 10 (71.4%) as High 1 and 3 (21.4%) as Low Risk. All 14 (100%) ImPrint+ patients were BP Luminal. In contrast, within the IDC MP High Risk ImPrint+ subgroup (n=328), 233 (71.0%) were High 2, 88 (26.8%) High 1 and 7 Low Risk (2.1%). Furthermore 193 (60.7%) were classified as BP Basal, 2 HER2 (0.6%) and 123 (38.7%) Luminal within this IDC RPS. Conclusions: This is the first study to investigate the distribution of Response Predictive Subtypes in ILC, which will be beneficial to optimize the treatment selection for patients with early-stage HR+/HER2- ILC. Though the percentage of ImPrint+ is lower in ILC, this study revealed a small subset of patients in ILC with potential response to Immunotherapy. Furthermore, these results underscore the heterogeneity of ILC tumors and generate further hypotheses to investigate the immune cell abundance in ILC compared to IDC and correlate immune cell abundance to ImPrint status. Table: Genomic and Tumor Characteristics of HR+HER2- ILC and IDC tumors Citation Format: Rita Mukhtar, Christina Yau, Denise Wolf, Adam Brufsky, Hannah Linden, Natasha Hunter, Reshma Mahtani, Abirami Sivapiragasam, Trevor Feinstein, Fengting Yan, Ian Grady, Priscilla McAuliffe, Michaela Tsai, Joyce O'Shaughnessy, Blanche Mavromatis, Sasha Davis, Josien Haan, William Audeh, Lavanya Samraj, FLEX Investigators' Group. Distribution of MammaPrint, BluePrint, and Response Predictive Subtypes based on ImPrint and Reprint in ER+/HER2- Invasive Lobular Carcinoma – A FLEX sub 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 PO4-02-03.

Abstract PO5-02-01: Concerning Discrepancies in Estradiol Levels in Premenopausal Women Receiving Abemaciclib and Ovarian Function Suppression

Abstract Background: Adjuvant abemaciclib in combination with endocrine therapy improves outcomes for patients with high-risk, hormone receptor-positive (HR+), HER2-negative early-stage breast cancer. In premenopausal women, the use of an aromatase inhibitor (AI) requires chemical or surgical ovarian function suppression (OFS). Our published case report of a premenopausal woman receiving adjuvant abemaciclib with elevated estradiol levels measured by the Abbott Alinity chemiluminescent microparticle immunoassay (CMIA) despite bilateral salpingo-oophorectomy (BSO) but low estradiol levels using liquid chromatography-mass spectrometry (LC-MS/MS) suggested an interference of abemaciclib with the immunoassay (PMID: 37124155). The aim of this study was to determine discrepancies in estradiol levels using CMIA compared to LC-MS/MS and subsequent treatment changes in a larger patient population. Methods: We conducted an IRB-approved retrospective review of premenopausal women with early-stage HR+ breast cancer treated with adjuvant OFS and abemaciclib at our institution from October 2021 to April 2023 who had at least 1 CMIA estradiol level drawn during abemaciclib therapy. Pathology, treatment plans, and lab data were abstracted from medical records. Postmenopausal estradiol levels were based on reference ranges of &amp;lt; 41 pg/mL using CMIA or &amp;lt; 15 pg/mL using LC-MS/MS. We utilized descriptive statistics to describe the population and management. Results: We identified 22 patients who met criteria for our review. The average age was 42.3 years, all had positive axillary nodes, 6 (27%) received neoadjuvant chemotherapy, and 15 (68%) received adjuvant chemotherapy. There were 14 (64%) patients who received leuprolide and 8 (36%) received goserelin, whereas 19 (86%) received AI and 3 (14%) received tamoxifen as their initial oral antiestrogen therapy. The majority of patients did not have baseline estradiol levels when starting OFS though after starting abemaciclib, 20 patients had CMIA estradiol levels in the premenopausal range, 9 of which had estradiol monitored by both CMIA and LC-MS/MS (Table 1). The average length of time from starting OFS to starting abemaciclib was 144.6 days with 1 patient switching from tamoxifen to OFS and AI after starting abemaciclib. Due to elevated CMIA estradiol, treatment changes included increased OFS dosage (5 patients), change of OFS (2 patients), and change to tamoxifen (3 patients). There were 6 patients who underwent BSO, 3 due to persistently elevated CMIA estradiol levels, 2 due to patient preference, and 1 due to a BRCA mutation. Following surgery, 2 patients had persistently elevated CMIA estradiol but low LC-MS/MS estradiol. The remainder of these patients did not have estradiol levels measured by CMIA. Conclusions: Our retrospective review demonstrated the likely interference of abemaciclib with the Abbott Alinity immunoassay as shown by 9 patients treated with OFS and abemaciclib with simultaneous premenopausal range CMIA estradiol levels and postmenopausal range LC-MS/MS estradiol levels. As up to 91% of patients in our study may have had a false positive estradiol level erroneously suggesting inadequate OFS, monitoring of estradiol levels using the CMIA assay in patients receiving adjuvant abemaciclib in addition to OFS could lead to changes in therapy that may be unnecessary. It is recommended that the LC-MS/MS assay be used when monitoring of estradiol levels is indicated in patients receiving abemaciclib concurrently with OFS. Table 1: Estradiol levels in patients receiving OFS and abemaciclib who had both CMIA and LC-MS/MS assays Citation Format: Alaina Kessler, Rima Patel, Emily Gallagher, Tianxiang Sheng, Damodara Rao Mendu, Amy Tiersten, Paula Klein, Aarti Bhardwaj, Anupama Goel, Joseph Sparano, Theresa Shao, Julie Fasano. Concerning Discrepancies in Estradiol Levels in Premenopausal Women Receiving Abemaciclib and Ovarian Function Suppression [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 PO5-02-01.

Abstract PO5-01-11: Breast Cancer Index and comparative analysis of late distant recurrence risk with results from the TEAM trial

Abstract Background: Individualized risk assessment of distant recurrence (DR) is critical for early-stage HR+ breast cancer patients, as prolonged risk of recurrence continues even after completing 5 years of adjuvant endocrine therapy. The Breast Cancer Index (BCI) is a guideline-endorsed, validated gene expression assay that provides an individualized risk of overall (0-10y) and late (5-10y) DR and predicts the likelihood of benefit from extended endocrine therapy. The current BCI assay reports prognostic risk estimates based on tamoxifen-treated patients from the Stockholm (STO-3) cohort for node-negative (N0) patients, enrolled between 1976 through 1990 and a retrospective cohort from Massachusetts General Hospital (MGH) for patients with 1 to 3 positive nodes (N1), diagnosed between 1993 and 2007, of which approximately 50% were tamoxifen-treated. More recently, additional validation was completed in the Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial, in which patients were enrolled between 2001 and 2006. Here, individualized DR risk estimates from the TEAM trial were compared with those from Stockholm and MGH cohorts. Methods: For the TEAM translational study, BCI testing was performed blinded to clinical outcome and BCI and BCIN+ risk scores were calculated as previously described. A total of 2910 postmenopausal patients with HR+ breast cancer, including 1285 N0 and 1625 N1 patients, who remained DR-free for five years were analyzed to determine the risk of late DR. Cox proportional hazard models using Breslow estimates were used to calculate the risk of late DR as a function of continuous BCI risk scores. Results: Late DR risk estimates from both the TEAM trial and the Stockholm/MGH cohorts are summarized in the table below. In N0 patients, comparison of 5-10y risk estimates of late DR observed in TEAM patients were higher than those in the Stockholm cohort for BCI scores less than 8.0, but reduced for BCI scores greater than 8.0. Risk estimates differed by 1.5% for a BCI score of 0 and -4.3% for a BCI score of 10. A similar pattern was observed for N1 patients between the TEAM and MGH cohorts, with risk estimates from TEAM trial being higher for BCI scores less than 8.0 but reduced for BCI scores greater than 8.0 compared to those from the MGH cohort. Conclusions: BCI prognostic validation in the TEAM trial enabled the characterization of DR risk that is more compatible with the current standard of care in the US, as postmenopausal patients were all treated with at least 2-3 years or 5 years of primary adjuvant endocrine therapy with an aromatase inhibitor. Results from the TEAM study provide a more representative assessment of late DR risk to guide individualized treatment decision-making for HR+ early-stage breast cancer patients. Table. Citation Format: John MS Bartlett, Yi Zhang, Gregory Pond, Jenna Wong, Keying Xu, Melanie Spears, Elizabeth Mallon, Karen Taylor, Annette Hasenburg, Christos Markopoulos, Luc Dirix, Caroline Seynaeve, Cornelis J.H. van de Velde, Daniel Rea, Adam Brufsky, Olle Stål, Dennis Sgroi, Catherine Schnabel, Kai Treuner, Jane Bayani. Breast Cancer Index and comparative analysis of late distant recurrence risk with results from the TEAM trial [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 PO5-01-11.

Abstract PO3-15-04: Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers

Abstract Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers Background: Neoadjuvant therapy (NAT) in HR+/HER2- breast cancers rarely leads to pathological complete response (pCR) and often doesn’t achieve substantial tumor shrinkage. Therefore, neoadjuvant therapy in HR+/HER2- breast cancers has the most value in the assessment of in vivo treatment response. For this purpose, biomarkers that can predict clinical and pathological response to systemic therapy could help inform treatment. The role of Oncotype DX testing in the management of early-stage HR+/HER2- breast cancer has been widely recognized in the adjuvant setting. However, no large prospective studies evaluating the Oncotype DX test in the neoadjuvant setting have clearly shown its predictive or prognostic utility to date. In this study, we evaluated the effect of the recurrence score (RS) on systemic treatment recommendations and its correlation to NAT response. Methods: Patients with clinically selected T2-T4 and/or clinically node positive HR+/HER2- breast cancer who were referred to BC Cancer Vancouver for consideration of NAT between September 2021 – April 2023 were screened for study eligibility. Suitable candidates who agreed to participate in the study had Oncotype DX testing on core biopsy specimens and Ki-67 testing on the core biopsy and final resection specimen. Clinico-pathological information, treatment regimens, operative details, and clinical, radiologic, and pathological responses were recorded. Results: Of the 66 patients who met eligibility criteria, 40 enrolled in the study comprising the accrual rate of 60.6 %. There were multiple factors that influenced patients and/or Oncologists participation in the study highlighting the low uptake of NAT in HR+/HER2- tumors. Technical feasibility of obtaining Oncotype DX from core biopsy samples was 95% which correlates with our previously reported data on a smaller cohort. The mean turnaround time from patient consent to RS report was 18.5 calendar days. The mean time from the initial consult to the start of NAT was 18.8 calendar days. Amongst all tumors tested, 28 % had RS equal or greater than 26 while only 2 % of participants had a score less than 10. Overall, 32 % of treatment recommendations were changed based on RS. Approximately 31% of patients who were initially recommended to receive neoadjuvant chemotherapy were spared from this treatment based on low RS. Conversely, 23.8% of patients who were recommended to pursue upfront surgery were escalated to chemotherapy due to a high RS. Approximately 88 % of the participants who were treated with neoadjuvant chemotherapy had a favourable clinical response and 38.5% had a complete clinical response. There were no pCR observed amongst patients who completed surgery after neoadjuvant chemotherapy, but half of them were rendered eligible for less surgery (either spared a mastectomy and/or an axillary dissection). Conclusions: Oncotype DX testing changed systemic treatment recommendations in one third of neoadjuvant patients and presents a unique opportunity for personalized medicine. Pre-operative testing thus influenced clinical decision-making, allowing treatment de-escalation and omission of chemotherapy in those with a low RS and conversely an earlier escalation of systemic therapy for those with a high RS. Turnaround time of the Oncotype DX assay on a core biopsy sample was acceptable and did not significantly delay treatment initiation. The benefit of the Oncotype DX assay prior to NAT was valuable for predicting in vivo response although pCR was not observed in any of the patients enrolled. Analyses are ongoing to further correlate RS to neoadjuvant response and to dynamic Ki-67 and MRI changes. Citation Format: Lidiya Luzhna, Stephen Chia, Mehrnoosh Pauls, Nathalie Levasseur. Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers [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 PO3-15-04.

Pilot testing a patient decision aid as a strategy to reduce overtreatment for older women with early-stage breast cancer

BackgroundDespite national guidelines recommending omission of sentinel lymph node biopsy (SLNB) and post-lumpectomy radiotherapy (RT) in older women with early-stage, hormone receptor-positive (HR+) breast cancer, these practices persist. This pilot study assesses whether a decision aid can target patient-level determinants of low-value treatments. MethodsWe adapted and pilot-tested a decision aid in women ≥70 years old with early-stage HR ​+ ​breast cancer. Primary outcomes included acceptability and appropriateness of the decision aid. Secondary outcomes included treatment choice and satisfaction with decision. ResultsTwenty-three patients enrolled in the trial. 19 completed survey one; 16 completed survey two. Primary outcomes demonstrated that 84% of patients agreed or strongly agreed the aid was acceptable and appropriate. Secondary outcomes demonstrated that 19% of patients underwent SLNB (below pre-intervention baseline), and 85% received adjuvant RT (change not statistically significant). ConclusionsWe demonstrate that a decision aid may effectively target patient-level factors contributing to overuse of low-value therapies.

Optimising Extended Adjuvant Neratinib Use in HER2+/HR+ Early Breast Cancer: Memo for Nurses

Neratinib (NERLYNX®) is indicated for the extended adjuvant treatment of adult patients with early-stage HR+/HER2-overexpressed/amplified breast cancer, who completed adjuvant trastuzumab-based therapy &lt;1 year ago. This infographic offers valuable guidance to nurses in effectively managing neratinib patients to ensure they reap the maximum advantages from this therapy.

Interventions to improve oral endocrine therapy adherence in breast cancer patients.

Oral endocrine therapy (OET) is recommended in prevention and treatment of hormone receptor-positive breast cancer (HR+ BC). Despite the reduced incidence, recurrence, and mortality, OET adherence is poor in this patient population. The aim of this study was to review the latest literature to identify effective interventions to improve medication adherence in patients taking OET for prevention or treatment of HR+ BC. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) framework was used to perform this review. We utilized PubMed, SCOPUS, EMBASE, Cochrane, and Web of Science to acquire articles using search terms including breast cancer, adherence, persistence, and acceptability. Inclusion criteria included publication in peer-reviewed journal, primary data source, longitudinal, patients on OET such as aromatase inhibitors (AIs) or selective estrogen receptor modulators (SERMs), measuring adherence, persistence, or acceptability. Out of 895 articles identified, 10 articles were included. Majority of patients had early-stage HR+ BC. Two out of two studies incorporating technological intervention, two out of three studies with text communication-based intervention, and three out of five studies with verbal communication-based intervention reported significant improvement in OET adherence and/or persistence. While the interventions tested so far have shown to improve OET adherence in HR+ BC patients in some studies, there is a need to design combination interventions addressing multiple barriers in this population. This study showcases effectiveness of novel interventions to improve OET adherence and the need to further develop patient-centered strategies to benefit all patients with HR+ BC.

Abemaciclib pharmacology and interactions in the treatment of HR+/HER2- breast cancer: a critical review.

Abemaciclib (ABE) in combination with endocrine therapy represents the mainstay treatment for either endocrine-resistant metastatic or high-risk early-stage HR+/HER2- breast cancer patients. Hence, an adequate knowledge of this agent pharmacodynamic, pharmacokinetic, and of its drug-drug interactions (DDIs) is crucial for an optimal patients management. Additionally, ABE interference with food and complementary/alternative medicines should be taken into account in the clinical practice. Several online tools allow to freely check DDIs and can be easily consulted before prescribing ABE. According to one of this instruments, ABE display the lowest number of interactions among the available cyclin-dependent kinase 4/6 inhibitors. Still, clinicians should be aware that online tools cannot replace the technical datasheet of the drug as well as a comprehensive clinical assessment for each patient. Here we critically review the main pharmacological features of ABE, then focusing on its potential interactions with drugs, food, and alternative medicine, in order to provide a guide for its optimal use in the treatment of HR+/HER2- breast cancer patients.

Exploring Breast Cancer Systemic Drug Therapy Patterns in Real-World Data.

To explore medications and their administration patterns in real-world patients with breast cancer. A retrospective study was performed using TriNetX, a federated network of deidentified, Health Insurance Portability and Accountability Act-compliant data from 21 health care organizations across North America. Patients diagnosed with breast cancer between January 1, 2013, and May 31, 2022, were included. We investigated a rule-based and unsupervised learning algorithm to extract medications and their administration patterns. To group similar administration patterns, we used three features in k-means clustering: total number of administrations, median number of days between administrations, and standard deviation of the days between administrations. We explored the first three lines of therapy for patients classified into six groups on the basis of their stage at diagnosis (early as stages I-III v late as stage IV) and the sensitivity of the tumor's receptors to targeted therapies: hormone receptor-positive/human epidermal growth factor 2-negative (HR+/ERBB2-), ERBB2-positive (ERBB2+/HR±), or triple-negative (TN; HR-/ERBB2-). To add credence to the derived regimens, we compared them to the National Comprehensive Cancer Network (NCCN): Breast Cancer (version 2.2023) recommendations. In early-stage HR+/ERBB2- and TN groups, the most common regimens were (1) cyclophosphamide and docetaxel, administered once every 3 weeks for three to six cycles and (2) cyclophosphamide and doxorubicin, administered once every 2 weeks for four cycles, followed by paclitaxel administered once every week for 12 cycles. In the early-stage ERBB2+/HR± group, most patients were administered carboplatin and docetaxel with or without pertuzumab and with trastuzumab (for six or more cycles). Medications most commonly administered in our data set (7,798 patients) agreed with recommendations from the NCCN in terms of medications (regimens), number of administrations (cycles), and days between administrations (cycle length). Although there is a general agreement with the NCCN Guidelines, real-world medication data exhibit variability in the medications and their administration patterns.

Barriers to gBRCA Testing in High-Risk HER2-Negative Early Breast Cancer.

Despite the OlympiA trial demonstrating that early-stage, high-risk, HER2- germline BRCA1 and BRCA2 mutation (gBRCAm) positive breast cancer patients can benefit from PARPi in the adjuvant setting, the gBRCA testing rate in early-stage HR+/HER2- patients remains suboptimal compared to that in early-stage TNBC patients. To better understand the perceived barriers associated with gBRCA testing in HR+/HER2- disease, a quantitative survey was conducted across stakeholders (n = 430) including medical oncologists, surgeons, nurses, physician assistants, payers, and patients. This study revealed that while payers claim to cover gBRCA testing, poor clinician documentation and overutilization are key challenges. Therefore, payers place utilization management controls on gBRCA testing due to their impression that clinicians overtest. These controls have led to healthcare professionals experiencing payer pushback in the form of reimbursement limitations and denials. The perceived challenges to gBRCA testing stem from the lack of consensus dictating which patients are high risk and should be tested. While payers define high risk based on the CPS + EG score from the OlympiA trial, HCPs adopt a broader definition including genomic risk scores, lymph node involvement, and tumor grade and size. A dialogue to harmonize risk classification and testing eligibility across stakeholders is critical to address this disconnect and increase gBRCA testing in appropriate patients.