Localized Breast Research Articles

Abstract PO4-07-02: Development of an Artificial Intelligence-based breast cancer detection model using Plasma Lipidomic Signature

Abstract Background: Mammography is the current diagnostic standard for breast cancer screening and monitoring. However, accessibility challenges, accuracy issues and patient discomfort all contribute to reduced patient compliance and utilization, resulting in a need for more effective diagnostic tools. An artificial intelligence (AI)-based lipidomic blood test may add significant value to early breast cancer detection rate and improve outcomes for patients. We have previously reported a series of lipidomic studies (n=793) and derived a lipid signature from plasma-enriched extracellular vesicles (EVs) that effectively distinguished people with localized breast cancer from cancer-free controls. Here we report the development of a breast cancer detection AI model from lipidomic data assessed directly using plasma samples. Methods: Lipids in both EVs and plasma collected from fasted breast cancer and control blood samples (n=256) were extracted and analysed by liquid chromatography-high resolution mass spectrometry (LC-HRAM-MS). Over 400 manually curated lipids were quantified. A bootstrapped analysis using Boruta, a robust and statistically rigorous feature selection algorithm based on random forest feature importance, was employed to identify cancer discriminatory lipid signatures in EV and plasma lipidomes consistently selected across 2000 bootstrap samples. The resulting lipid signature was then used to train an ensemble of 18 distinct machine learning models for cancer status prediction using a majority vote to aggregate the individual predictions. Model performance and variability were assessed over 2000 iterations of leave-group-out cross-validation (LGOCV) using an 80/20 train-test split. Average patient-level predictions across LGOCV iterations were recorded for both EV-and plasma-derived models and the two modalities were compared using an exact paired samples test (McNemar’s test). Results: Both the EV- and plasma-derived lipid signatures performed well in distinguishing breast cancer samples from controls. The development of a bioinformatics AI pipeline enabled the creation of a robust ensemble model achieving an F1 score of 0.89 in plasma with LGOCV. The final plasma ensemble predictive performance of 86.1% (±4.5%) in accuracy, 91.4% (±5.4%) in sensitivity, and 78.7% (±8.6%) specificity was achieved, which is comparable to that of EV (accuracy: 86.1±4.4%, sensitivity: 90.4±5.3%, specificity: 80.2±8.7%). Paired samples analysis using McNemar’s test indicated no significant differences between models trained on EV- and plasma-derived lipid signatures in either the sensitivity (p=0.65), specificity (p=0.49), or accuracy (p=0.42). Conclusion: The initial study demonstrated the high performance of a plasma-enriched extracellular vesicle-derived lipid biomarker signature for early breast cancer detection. Direct assessment of the lipidomic signature from plasma showed promise in simplifying the test. Assessing plasma directly offered advantages in terms of scalability, higher throughput, and ease of implementation. Further verification of the lipid signature in an upcoming study involving 500 plasma samples is planned. Ongoing studies will further optimize the plasma lipidomic signature and strengthen our AI pipeline. These findings support the potential clinical application of AI-based lipidomic profiling as a blood-based screening tool for breast cancer detection. Citation Format: Ameline Lim, Cheka Kehelpannala, Fatemeh Vafaee, Forrest Koch, Dana Pascovici, Desmond Li, Kerry Heffernan, Gillian Lamoury, Amani Batarseh, Bruce Mann. Development of an Artificial Intelligence-based breast cancer detection model using Plasma Lipidomic Signature [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 PO4-07-02.

Abstract PO1-14-09: Age-related remodeling of the systemic and breast microenvironment promotes a tumor-permissive locale for ER+ breast cancer in older women

Abstract Introduction: The peak incidence of ER+ breast cancer occurs in women around the age of 70. Compared to younger cohorts, we and others have shown that older patients with ER+ breast cancer have an enrichment of luminal disease and experience fewer recurrences, suggesting overtreatment. Differences in the biological phenotypes of tumors in older women remain poorly understood and treatment remains challenging as older patients are underrepresented in clinical trials. In this study, we hypothesized that aging alters both local and systemic hormones and inflammatory cytokines, creating a permissive environment for tumor formation and growth. To address this hypothesis, we employed a systems biology approach across multiple model systems and tissue samples. Methods: Our study included specimens from two cohorts of patients: (1) n = 90 women without breast cancer obtained from the Komen Tissue Bank, from whom we obtained matched plasma and non-cancerous breast tissue (n = 30 across age groups comprising of young donors (35-45yo), middle-aged donors (55-69yo), and older donors (≥ 70yo); and (2) n = 115 women with ER+ breast cancer (n = 25 young patients, n = 57 middle-aged patients, and n = 33 older patients) obtained from our institutional biobank, including matched plasma, tumor tissue, and tumor-adjacent tissue. From each of these sets of specimens, we measured estrogen disposition using mass spectrometry, a 22-plex panel of inflammatory markers, and transcriptomic changes using RNA-seq. Using scRNA-seq and multiplexed IHC, we further characterized the immune changes that occur with age. Lastly, we used an aged, carcinogen-induced ER+ tumor model in F344 rats (obtained from the NIA) to model tumor development and growth. Results: In the plasma, estradiol (E2) drastically decreased in post-menopausal women, leaving estrone (E1) as the predominant circulating estrogen in older women. However, the breast tumor microenvironment (TME) showed comparable levels of E1 and E2 across age groups. Multi-class concordance analysis of breast cancer tissue from RNA revealed significant increases in gene expression of the HSD17B7 enzyme and decreases in HSD17B2 enzyme across age, likely elevating local E1-to-E2 conversion and yielding high local E2 levels despite low circulating levels specifically in older women. In older patients with ER+ breast cancer, there was a significant increase in a chemokine network characterized by CCL2 and CXCL9 within the TME. scRNA-seq revealed enrichment of inflammatory M2-like macrophages in the aged TME. Immune dysfunction and decreased immunosurveillance in older patients manifested with widespread decreases in the presence of cytotoxic lymphocytes and decreased pathway enrichment of key immune pathways, such as JAK/STAT and IFNy signaling. mIHC analysis revealed decreases in CD4 and CD8 T cells and increases in M2-like macrophages in older patients in both tumor and stromal regions. Lastly, in the carcinogen-induced F344 rat model, aged rats (~ 24mo, human equivalent 60-70yo) had a shorter tumor-free interval than the younger rats (~ 4-6mo, human equivalent 20-30yo), likely due to increases in tumor-promoting inflammation and decreased immune surveillance. Ongoing mechanistic work is focused on macrophage-patient derived organoid co-cultures evaluating the functional relevance of E2, CCL2, and CXCL9 in shaping the aged TME. Conclusions: Our study of systemic and local breast hormones and cytokines in both healthy individuals and breast cancer patients showed that older women with ER+ breast cancer harbor different systemic and local environments compared to younger women. The aged TME is characterized by high E2, cytotoxic lymphocyte depletion, and immune dysfunction, creating a permissive environment for tumor formation. Future translational work should be aimed at chemo-preventative strategies to reduce the age-related chronic inflammation and immune dysfunction. Citation Format: Neil Carleton, Jian Zou, Sanghoon Lee, Dixcy Jaba Sheeba John Mary, Ruxuan Li, Jennifer Atkinson, Ziyu Huang, Hatice Osmanbeyoglu, Peter Lucas, Emilia Diego, Michael Lotze, George Tseng, Jagmohan Hooda, Ioannis Zervantonakis, Priscilla McAuliffe, Steffi Oesterreich, ADRIAN LEE. Age-related remodeling of the systemic and breast microenvironment promotes a tumor-permissive locale for ER+ breast cancer in older 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 PO1-14-09.

Abstract PO4-16-08: Prognostic factors for tumor recurrence after breast-conserving and radiotherapy treatment for early invasive breast cancer: ten years of results in a referral center in Mexico City

Abstract Background: Breast cancer is the most common malignancy in the world, reporting more than 2 million new cases in 2020. In early stages, patients undergo primary surgery. Breast-conserving surgery (BCS) has generally been accepted as a treatment for invasive breast cancer, findings at 20 years still show that lumpectomy and breast irradiation, as compared with mastectomy, have no significant difference in overall survival among the treatment groups. Approximately 10-15% of patients will develop local or systemic recurrence in 5 to 10 years. Factors such as young age (< 45 years), close/positive margins, no breast radiation, are associated with ipsilateral breast tumor recurrence. High grade has been related to distant metastasis. The mortality trend is upward due to a higher incidence of the disease and earlier detection. Methods: This is an observational and retrospective cohort study, which included patients with early breast cancer, who were treated with conserving surgery and received radiotherapy, at the Breast Oncology Service at the UMAE Gineco 4 "Luis Castelazo Ayala" during the period from January 2012 to December 2022. The aim of our study was to describe the prognostic factors associated with disease-free survival (DFS) and overall survival (OS) in patients with localized breast cancer treated with BCS. DFS was defined as time from surgery to recurrence event (local recurrence, distant recurrence, contralateral breast cancer, second primary cancer, or death from any cause) whichever occurred first. For statistical analysis, Kaplan Meier and Log-rank methods were used for survival analysis. Cox proportional hazard model was used for multivariate analysis. Results: We included 399 patients, the median follow-up was 88 months (95%CI 86-91). Median age was 59 years. The most common pathological stage was IA in 44.9%, the predominant immunophenotype was luminal A in 56.1% of patients, follow by luminal B in 19.3% and 13% were triple negative. Management of axilla with sentinel node biopsy occurred in 50.1% and 49.9% underwent to lymph node dissection. Regarding surgery outcomes 40.4% of the patients required widening of the margins, 5% of the patients remained with close surgical margins ≤2 mm, 7.5% had complications associated with the surgery, and none related death ocurred. All patients received adjuvant radiotherapy, the median time to initiation was 32 weeks (range 3-70) and 65.4% received adjuvant chemotherapy. Recurrence events occurred in 15.5% of patients, local 2.8%, systemic 8.8%, contralateral breast cancer 1.7%, and second primary 2.2%. Estimated disease-free survival at 5 and 10 years were 86.6% and 74.2%, respectively. In the multivariate analysis independent prognostic factors for DFS were: lobular histology HR 2.95 (95%IC 1.5-5.7), tumor size ≥ 2cm HR 1.95 (95%IC 1.1-3.6), close surgical margins HR 2.62 (95%IC 1-6.6), and ER low expression (1-10%) HR 4.39 (95%CI: 1.6-12.4). Estimated OS at 5 and 10 years for patients who experienced recurrence were 78.4% and 47.4% and for patients without recurrence were 96.8% and 93.5%, respectively (adjusted HR: 10.4, 95%CI: 5.2-20.6). Conclusion: These results suggest that patients with early breast cancer treated with conserving surgery and radiotherapy with risk factors such as lobular carcinoma, tumor size ≥2cm, close margins, and low expression of estrogen receptors have a high risk of recurrence and significantly decreased overall survival at 5 and 10 years. Citation Format: Nayeli Ortega-Avila, Yuly A. Remolina-Bonilla, Janett Caballero-Jasso. Prognostic factors for tumor recurrence after breast-conserving and radiotherapy treatment for early invasive breast cancer: ten years of results in a referral center in Mexico City [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 PO4-16-08.

Abstract PO2-18-07: Ultrasound – guided Interstitial Laser therapy for Stage I Breast Cancer: a phase 2 trial

Abstract Background: Screening programs are changing the scope of breast cancer, with a growing number of patients diagnosed at a nearly stage. The current standard treatment (breast conservation and radiation therapy) offers an excellent prognosis for these patients. Besides tumor removal, other techniques can be used to destroy a mass in place. A range of minimally invasive techniques holds promise on local breast tumor ablation (i.e. thermotherapy, cryotherapy, and irreversible electroporation). Previous studies with Interstitial laser thermotherapy (ILT) for breast cancer report mean ablation rates between 33% to 87%. Most common cited causes for failure are equivocal tumor size estimation, inadequate technique and the learning curve. Objective: Improve the ILT technique and achieve better ablation rates through the evaluated procedure. Methods: A prospective study with 15 patients with Stage I invasive breast cancer, presented as a unique lesion as inclusion criteria was conducted. MRI and US were used to estimate the primary tumor volume and rule out multicentric/multifocal disease. ILT ablation was performed using an Echolaser unit (Elesta) through percutaneous laser optical fibers with a US-guided insertion in the lesion center. All procedures were performed under local anesthesia and sedation. The post procedure image reevaluation included an immediate US after the ablation and a new MRI about 3 hours after the procedure. The definitive proposed surgical treatment was carried out 8-13 days after the ILT ablation. Results: Eighteen patients were included in the study, of whom 14 (with 15 lesions) completed the protocol. The mean tumor size measured by MRI was 13.7 (4-20) mm. The mean treatment time was 10.1 minutes and all patients went home the same day, reporting only mild (78%) or moderate (22%) pain, controlled with analgesics. The mean ablation index, evaluated by H&E and CK8/18, was 61,5% (0 -93%) and when only tumors under 15 mm were considered the mean ablation index was 75% (30%-93%). The MRI performed after ablation procedure showed a large area of edema around the clip in all cases. The sensitivity and specificity to detect residual tumors were 1.0 and 0.84, respectively, when the residual tumors were larger than 15% of the original tumor size . Conclusions: These preliminary results suggest that laser therapy can eliminate viable neoplastic tissue in vivo. To achieve better results, standardization in patient selection, power and energy applied, should be considered. There are several advantages of ILT for breast cancer treatment, including preserving the structure and function of breast, no bleeding, no scaring and no radiation. More studies refining the technique should be conducted to allow the implementation of ILT as an alternative to surgical treatment in early breast cancer. Citation Format: Danielle Matsumoto, Silvio Bromberg, Marcus Corpa, Rodrigo Garcia, Guilherme Mariotti, Monica Rudner, Angela Waitzberg, Afonso Nazário, Gil Facina. Ultrasound – guided Interstitial Laser therapy for Stage I Breast Cancer: a phase 2 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 PO2-18-07.

Abstract PO2-09-10: Addressing Breast Cancer Disparities: Co-Creating Digital Interventions with Patients, Navigators & the Community to Address Social Determinants of Health in the Memphis Statistical Area

Abstract Background: The Memphis Statistical Area, which covers counties in Arkansas, Mississippi, and Tennessee, leads in disparities in mortality rates between Black breast cancer patients compared to White counterparts1. Urban Health Education & Support Services (UHESS), in partnership with RabbleHealth, and West Cancer Center & Research Institute (WCCRI), initiated a solutions-oriented, community-based scalable initiative in January 2023 to measurably address social determinants of health (SDOH), which often drive cancer inequities that disproportionately impact individuals of marginalized communities. By leveraging a community-driven, co-creation sustainable approach, the team sought to measurably improve breast cancer equality utilizing digital enablement and the knowledge of local breast cancer survivors and leading healthcare professionals, including navigators. Methods: A four-phase approach was leveraged to 1. improve access to locally available breast cancer services in communities that are traditionally underserved and 2. measure the public health impact against root causes of breast inequities (i.e., care pathway metrics), and 3. create a repeatable, scalable model to expand to other underserved communities. In Phase 1, UHESS leveraged the Mid-South Regional Breast Cancer Coalition, which convenes ten local breast cancer patient advocacy organizations, to recruit focus groups for co-creation throughout all phases of the initiative. The working group consisted of eight representatives from a variety of Memphis-based cancer organizations, faith-based organizations, navigator programs, and WCCRI. This phase centered around establishing trust with the local patient advocacy community. In Phase 2, an initial patient survey was circulated to identify key resources that reduce health inequities and barriers to access. Human-centered design facilitators supported a series of Listen & Learn workshops with patients to convey root causes of gaps in access to relevant services and with navigators to understand professional needs of navigators and scale the ability improve patient access to resources. To co-create a solution, facilitated patient and navigator workshops were held in Phase 3 to gather patient-centric user experience and design enhancements for a digital patient engagement app. These requirements as well as navigator-defined metrics needs were digitized and organized by SDoH. Phase 4, the Deploy & Measure phase, will begin in September of 2023 and the community-based deployment model focuses on three drivers including: (a) embedding within navigator workflow, (b) activating faith-based organizations, and (c) leveraging societies. Health equity performance data will be analyzed weekly to rapidly target those ZIP codes with the greatest need. Results: Co-design efforts included over 50 members of the Greater Memphis community and final initiative results will be presented at the meeting. Planning for further research regarding community impact and model scalability is already underway. Conclusion: By leveraging a community-driven, co-creation sustainable approach, this model enables a better way to measurably improve breast cancer equality utilizing digital enablement and the knowledge of local breast cancer survivors and leading healthcare professionals, including navigators. Initiative Funding Acknowledgements: Gilead Life Sciences & Blue Cross Blue Shield of Tennessee Foundation 1. Vidal G, Bursac Z, Miranda-Carboni G, White-Means S, Starlard-Davenport A. Racial disparities in survival outcomes by breast tumor subtype among African American women in Memphis, Tennessee. Cancer Med. 2017 Jul;6(7):1776-1786. doi: 10.1002/cam4.1117. Epub 2017 Jun 14. PMID: 28612435; PMCID: PMC5504313. Citation Format: Gregory Vidal, Stacey Tinianov, Aubrey Kelly, Andrea Curry, Carla Baker. Addressing Breast Cancer Disparities: Co-Creating Digital Interventions with Patients, Navigators & the Community to Address Social Determinants of Health in the Memphis Statistical Area [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 PO2-09-10.

Abstract PO3-20-12: A Case Report on the Management of a Patient with Local Breast Cancer, BIA-ALCL and Radiation Induced Metastatic Angiosarcoma: A Multidisciplinary Approach

Abstract A Case Report on the Management of a Patient with Local Breast Cancer, BIA-ALCL and Radiation-Induced Metastatic Angiosarcoma: A Multidisciplinary Approach Abstract: Breast cancer recurrence presents a complex challenge in clinical practice. We present the case of a 60-year-old female with a history of stage 2A right breast cancer diagnosed on 12/1/2013. The patient underwent bilateral mastectomy and adjuvant chemotherapy, followed by breast reconstruction. The patient subsequently developed asymmetric right breast swelling, which was biopsied and was positive for T lymphocyte markers CD30, CD43, CD45, CD4 and she was diagnosed with anaplastic large cell lymphoma in 12/14/2018, which was thought to be associated with her breast implants. In May 2022, a right chest wall mass was detected, which demonstrated growth and increased vascularity on imaging. A biopsy on 5/5/22 confirmed poorly differentiated carcinoma initially thought to be a secondary intraductal carcinoma of the breast, invading the chest wall by metastasis or direct extension, negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Further workup confirmed this mass to be angiosarcoma, most likely associated with the patient’s prior radiation therapy. The patient was started on neoadjuvant carboplatin/paclitaxel/pembrolizumab on 6/9/2022, and continued with Doxorubicin/Cyclophosphamide and pembrolizumab, which was completed on 11 November 2022. Imaging studies post-treatment showed a slightly smaller mass in the right mastectomy bed, indicating a partial response to treatment. However, a subsequent PET scan revealed a recurrence of breast cancer in the right chest wall. Considering the patient's history of prior radiation therapy and the inability to administer further radiation, the treatment plan was revised. She underwent reconstructive chest wall surgery on 1/4/2023, with complete resection and negative margins. She started on adjuvant pembrolizumab planned for one year, but the patient presented on 3/3/2023 with the growth of a chest wall mass and bleeding, consistent with progression. Liquid Tempus testing was obtained but negative for an actionable target. Options such as hyperthermia, enrollment to clinical trial, and re-irradiation were discussed, and the patient was restarted on weekly paclitaxel on 3/31/2023 due to a previous response. The patient had further local disease progression on 5/26/2023, and this regimen was stopped. The patient is planning to get Tempus testing on tumor tissue and start the next line palliative regimen with either doxorubicin or gentamicin and repeat re-irradiation if no response to these regimens. This case report highlights the challenges in managing breast cancer therapy-induced adverse conditions with two secondary tumors, both associated with the patient’s prior therapy. The importance of a multidisciplinary approach, including medical oncology, surgical oncology, radiation oncology, and sarcoma specialists, is emphasized. The use of molecular testing and consideration of clinical trials may provide additional treatment options. Further research and clinical trials are warranted to optimize the management of recurrent breast cancer with transformation to rare histological subtypes such as angiosarcoma. Citation Format: Liubou Varanitskaya, Serhan Unlu, Christina Clemow. A Case Report on the Management of a Patient with Local Breast Cancer, BIA-ALCL and Radiation Induced Metastatic Angiosarcoma: A Multidisciplinary Approach [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 PO3-20-12.

Abstract PO4-01-01: Prognostic Impact of Adjuvant Trastuzumab for the Treatment of Localized Stage I Breast Cancer - Single Tertiary Center Experience

Abstract Prognostic Impact of Adjuvant Trastuzumab for the Treatment of Localized Stage I Breast Cancer – Single Tertiary Center Experience Sasha Sapon-Cousineau, Marie Florescu, Danielle Charpentier, Rami Younan, Erica Patocskai, Saima Hassan, Kerianne Boulva, Jean-Pierre Ayoub Centre hospitalier de l’Université de Montréal, Montréal, Québec, Canada The HER2 oncoprotein is an established therapeutic target, and the combination of adjuvant chemotherapy and targeted anti-HER2 therapy substantially reduces the risk of recurrence and death over chemotherapy alone in high-risk operable breast cancers that overexpress HER2. However, most studies demonstrating the benefits of anti-HER2 treatments have focused on cohorts at high risk of recurrence. Limited data exists for low-risk cancers to justify this treatment. We performed a retrospective study from 263 patients treated at our oncology center at the Centre hospitalier de l’Université de Montréal between 2006 and 2019 for HER2-positive, N0 or N0(i+) and T1mic to T1c breast cancers. A total of 227 patients were included, 149 (57%) with anti-HER2 treatment and 78 (30%) without. Patients had a single site of HER2-overexpressing invasive breast neoplasia with a follow-up of at least 6 months. Primary outcome was overall survival. Secondary outcomes were disease-free survival and the impact of tumoral and demographic factors. Median follow-up period was 6.7 years. Overall survival at 5 years was 97% (CI 94, 100) for the group with anti-HER2 treatment versus 92% (CI 85, 98) for the group without anti-HER2 treatment. The difference in overall survival between the two treatment groups increased with tumor size. Disease-free survival at 5 years was 93% (CI 88, 87) for the group with anti-HER2 treatment versus 82% (CI 74, 92) for the group without anti-HER2 treatment. In subgroup analysis, age and tumor size had a significant impact on the difference in disease-free survival between groups. Our study demonstrates the significant impact of anti-HER2 targeted therapies on overall survival and disease-free survival for patients with small, HER2 positive localized breast cancers. Further benefit is seen in certain subgroups, such as older patients and those with tumors larger than 1.0 cm, and this should be considered when determining appropriate treatment. Citation Format: Sasha Sapon-Cousineau, Marie Florescu, Danielle Charpentier, Rami Younan, Erica Patocskai, Saima Hassan, Kerianne Boulva, Jean-Pierre Ayoub. Prognostic Impact of Adjuvant Trastuzumab for the Treatment of Localized Stage I Breast Cancer - Single Tertiary Center Experience [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 PO4-01-01.

Abstract PO5-01-09: Exploring cellular heterogeneity of localised breast cancers

Abstract Breast cancer is a heterogeneous disease at multiple levels, ranging from subtype differences between patients (inter-patient heterogeneity) to the diverse composition of malignant cells, heterogeneity of hormone receptor (HR) expression and cellular makeup within single breast cancer samples (intra-tumour heterogeneity). Despite an increase in the number of effective therapies available, many patients will experience an incomplete treatment response and subsequent relapse. These adverse treatment outcomes may be attributed to the often overlooked but critical factor of cellular heterogeneity. In order to gain deeper insights into intra-tumour heterogeneity, we have applied single-cell technologies on a cohort comprising 250 primary, untreated breast cancers. We have optimized methods for tissue cryopreservation, eliminating the need for fresh sample processing, and multiplex tissue profiling. Together, these are cost-efficient processes that allow for improved handling of small tissue sizes, such as biopsies, and reduce batch effect. To ensure accurate and reliable data processing, we have developed a scalable computational workflow that includes benchmarked methods for sample SNP-demultiplexing, doublet detection, high-resolution cell annotation and cellular integration. Finally, we are extending our existing methods1 to study the cellular heterogeneity of breast cancers. Our method, scSubtyper, explores the phenotypic differences between malignant cells within tumours, by comparing each single cell to distinct features associated with different molecular subtypes and assigning each cell to one of these subtypes. Our previous study1 and preliminary results of this project revealed that over 90% of the samples exhibit a mix of malignant cells of different subtypes, and 50% of samples contain cells that have characteristics of all subtypes, demonstrating cellular heterogeneity exists not only exists between malignant cells, but also within malignant cells of a tumour. Our second approach, known as ecotyping, assesses patterns of cell type frequencies across samples and groups them based on similarity of these co-occurences. Our preliminary results have revealed the existence of 5 ecotypes that lack significant associations with samples clinical subtypes. Applying the same approach exclusively within the HR-positive samples identified 4 ecotypes characterized by distinct abundances of immune and stromal cells. This analysis revealed that ecotypes are not a simple surrogate for clinical and molecular subtypes, but their presence could drive different response to treatment. Together, our high-throughput tissue processing and computational approaches to studying intra-tumour heterogeneity are now being applied to our large, well annotated, clinical cohort. Supported by the preliminary results, we hypothesize that this study will play a vital role in optimizing breast cancer patient stratification to improve treatment management and outcome. 1. Wu, Sunny Z., et al. "A single-cell and spatially resolved atlas of human breast cancers." Nature genetics 53.9 (2021): 1334-1347. Citation Format: Beata Kiedik, Daniel Roden, Kate Harvey, Ghamdan Al-Eryani, Sunny Wu, Mun Hui, Sandra O'Toole, Elgene Lim, Charles Perou, Alex Swarbrick. Exploring cellular heterogeneity of localised 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 PO5-01-09.

Abstract PO2-19-03: Phase 2 study of response-guided neoadjuvant sacituzumab govitecan in patients with localized breast cancer (NeoSTAR)

Abstract Background: Optimizing treatments for localized breast cancer is key to preventing metastatic recurrences and reducing mortality. Sacituzumab Govitecan (SG) is a novel antibody-drug conjugate in which the topoisomerase 1 inhibitor SN-38 (the active metabolite of irinotecan) is coupled to a humanized monoclonal antibody targeting the antigen Trop-2, which is highly expressed in triple negative breast cancer (TNBC). SG is FDA approved for patients with metastatic hormone receptor-positive (HR+) and TNBC. However, efficacy in localized BC is not known. The NeoSTAR clinical trial is evaluating SG in the neoadjuvant (NA) setting for participants with localized breast cancer. Cohort A1 evaluating NA SG monotherapy in localized TNBC is completed, and now cohorts A2 (SG + pembrolizumab (P) for TNBC), B1 (SG monotherapy for HR+ BC), and C (SG + P for HER2- inflammatory breast cancer (IBC)) are enrolling. Trial design: This is a single-arm phase II study of NA SG or SG + P with multiple cohorts across different breast cancer subtypes. In all cohorts, SG is administered via an IV infusion on days 1 and 8 of each 21-day cycle at a starting dose of 10 mg/kg for 4 cycles. For cohorts A2 and C, pembrolizumab is given on day 1 of each cycle. For A2 and B1, after 4 cycles, participants who have biopsy-proven residual disease will have the option to receive additional standard NA therapy at the discretion of the treating physician and subsequently proceed to surgery. Those with a complete response on imaging may proceed directly to surgery. If pathological complete response (pCR) is achieved after 4 cycles of SG + P, participants on A2 will remain on study and receive adjuvant weekly paclitaxel and carboplatin for 12 weeks along with continuation of P to complete a total of one year of the PD-1 inhibitor; participants on B1 will receive adjuvant therapy at the discretion of the treating physician, with the option to continue P to complete a total of one year. On cohort C, after 4 cycles of SG + P, dose-dense doxorubicin + cyclophosphamide + P for 4 cycles will be given before considering surgery. A baseline research biopsy is required for all cohorts, as well as tissue collection following treatment with SG (either at surgery or via biopsy prior to additional NA therapy). Eligibility criteria: Participants ≥ 18 years of age with previously untreated localized breast cancer as determined by the local institution will be enrolled. For A2, participants must either have a primary tumor >2 cm or be node positive. For B1, participants with anatomic clinical stage II-III breast cancer with primary tumor > 1.5 cm and high genomic risk are eligible. For the IBC cohort (C), participants with T4d and any N are eligible. An ECOG performance score of 0 or 1, and adequate bone marrow, hepatic, and renal function is required. Study Objectives: The primary objective is to assess the pCR rate in breast and lymph nodes (ypT0/isN0) with SG + P (A2), SG (B1), or SG + P followed by AC + P (C). Secondary objectives include assessment of overall response rate, evaluation of the safety and tolerability of SG or SG + P (CTCAE v5.0), event-free survival (EFS), and quality of life (EORTC QLQ-C30). Exploratory objectives include assessment of potential predictive biomarkers, including Trop-2 expression, DNA damage response markers and immunological markers, as well as changes in cell free DNA with SG. Statistical methods: The primary analysis is based on the estimated pCR rate with SG or SG + P and will be provided as a proportion (with two-sided 95% confidence interval). Each cohort will follow a Simon two-stage design. EFS will be analyzed using Kaplan-Meier methods and descriptive statistics. Target Accrual: 50 participants (A2), 56 participants (B1), 39 participants (C) Contact: Dr. Laura Spring (LSpring@mgh.harvard.edu) Clinicaltrials.gov #: NCT04230109 Citation Format: Laura Spring, Ana Garrido-Castro, Filipa Lynce, Nadine Tung, Rachel Abelman, Lianne Ryan, Megan Moran, Elizabeth Mittendorf, Leif Ellisen, Sara Tolaney, Aditya Bardia. Phase 2 study of response-guided neoadjuvant sacituzumab govitecan in patients with localized breast cancer (NeoSTAR) [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 PO2-19-03.

Abstract PO2-27-06: ANXA9 facilitates the exocrine secretion of S100A4 and promotes pleural metastasis in breast cancer

Abstract Metastasis to distant organs stands as the primary contributor to mortality in cases of breast cancer. While localized breast cancer boasts a 5-year survival rate of roughly 99%, this figure drastically declines to approximately 26% for patients afflicted with distant metastasis. Regrettably, the current therapeutic landscape lacks efficacious and targeted interventions for the treatment of metastatic breast cancer. Our investigation has revealed a significant upregulation of S100A4 in metastatic breast cancer tissues, with notably high expression observed in the malignant pleural effusion of patients in advanced stages of the disease. Upon acceptance of the effective treatment, the expression of S100A4 in malignant pleural effusion decreased, along with a decrease in several cytokines, including IL-6, IL-8, CCL2, and CCL5. The breast cancer cellular models demonstrated that ANXA9 has the ability to regulate the excretion of S100A4 from cells into the surrounding medium. Similarly, the mice model of pleural metastasis indicated that the downregulation of ANXA9 (sh-ANXA9) resulted in decreased levels of S100A4 and cytokines IL-6, IL-8, CCL2, and CCL5 in the mice's hydrothorax. Additionally, our findings suggest that ANXA9 regulates the excretion of S100A4 through phosphorylation of ANXA9. The cellular membrane harbored phosphorylated ANXA9, which exhibited two phosphorylation sites. Upon mutation of these sites, the level of ANXA9 phosphorylation decreased, leading to a reduction in the exocrine release of ANXA9 from cells into the medium. Our research further revealed the significant involvement of ANXA9 in facilitating the progression of breast cancer, thereby suggesting that therapeutic interventions targeting ANXA9 could prove efficacious in treating metastatic breast cancer. This work was supported by Shanghai Sailing Program to Dengfeng Li (No. 20YF1437800), grant from the National Natural Science Foundation of China to Dengfeng li (No. 82103454) and grant from the National Natural Science Foundation of China to Lin Fang (No. 82073204). Citation Format: Xiqian Zhou, Dengfeng Li, Lin Fang, Junyong Zhao. ANXA9 facilitates the exocrine secretion of S100A4 and promotes pleural metastasis in 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 PO2-27-06.

A QUALITATIVE EXPLORATION OF THE EFFECT OF A METASTATIC BREAST CANCER DIAGNOSIS ON PHYSICAL ACTIVITY AND QUALITY OF LIFE

BACKGROUND Physical activity is beneficial for people living with metastatic breast cancer, a cancer that has spread to other body parts such as liver, lungs and lymph nodes, but less is known about patient views on supporting them in an active lifestyle. Through a qualitative scope this study aimed to investigate the effect of a metastatic breast cancer diagnosis on physical activity and quality of life aiming to capture exercise motivators, barriers, and preferences to inform and introduce feasible and effective physical activity in treatment plans. METHODS This study involved semi-structured interviews with eight female participants from the local Metastatic Breast Cancer Support Group in Portsmouth. RESULTS Reflexive thematic analysis was conducted on the data, and five higher order themes were developed: (i) Life is affected by diagnosis and treatment, (ii) Limitations to being more physically active, (iii) Physical activity’s impact on quality of life, (iv) Factors supporting/enhancing physical activity and quality of life, and (v) Actions to support physical activity and quality of life. Generally, participants reported that living with metastatic breast cancer had negatively altered their quality of life, including their ability to be physically active. Perceptions of the introduction or continuation of physical activity were welcomed. Despite the benefits and factors found to support physical activity engagement several barriers were identified, such as treatment focus and exercise misconceptions. CONCLUSION Metastatic breast cancer impacts quality of life and the ability to be physically active, being active is generally perceived to be beneficial, and social and environmental support is important to being physically active.

The Feasibility of Omission of Postoperative Radiotherapy in Japanese Patients With Early Breast Cancer Treated With Breast-Conserving Surgery.

Background This study was aimed at analyzing the impact of postoperative radiotherapy (PORT) after breast-conserving surgery (BCS) on Japanese patients with early-stage breast cancer and exploring the potential of PORT omission. Materials and methods Data from 794 patients with early-stage breast cancer (T1-2, N0-1), who underwent BCS with (n = 310) or without PORT (n = 484) were retrospectively analyzed. Local control (LC) rate and breast cancer-specific survival (BCSS) were compared between the groups that received and did not receive PORT in the whole cohort and low-risk cohort (i.e., the cohort with negative surgical margin, lymph node negativity, and estrogen receptor positivity, excluding young age of 49 or less), and in low-risk subgroup using propensity-score matching. Results PORT was associated with better LC but not BCSS in the total population. In the low-risk cohort, the incidence of local recurrence in patients without and with PORT was 5.3% and 4.8%, respectively, at 10 years (p = 0.591), and 7.8% and 4.8%, respectively, according to propensity-score matching (p = 0.485). Conclusion PORT improved LC in the total population, but not BCSS or overall survival (OS). In the low-risk group analysis (negative surgical margin, lymph node negativity, estrogen receptor positivity, and age50 years or more), equivalent LC, BCSS, and OS were foundincluding propensity-matched comparison.Therefore, this study showed that the omission of PORT could be a treatment option for low-risk Japanese patients.Further multi-center prospective studies are warranted to validate these findings and reduce the unnecessary burden of PORT for patients and institutions.

P6. Local Breast Microbiome in Tissue Expander Reconstruction and Change over Time with Antibiotics

P6. Local Breast Microbiome in Tissue Expander Reconstruction and Change over Time with Antibiotics

Dynamic Projection of Medication Nonpersistence and Nonadherence Among Patients With Early Breast Cancer.

Oral endocrine treatments have been shown to be effective when carefully adhered to. However, in patients with early breast cancer, adherence challenges are notable, with 17% experiencing nonpersistence and 41% nonadherence at least once. To model the persistence of and adherence to oral anticancer treatment of a patient with localized breast cancer. This cohort study was conducted using anonymous reimbursement data belonging to French female patients with breast cancer, extracted from the French Health Insurance database from January 2013 to December 2018. Data analysis was conducted from January 2021 to May 2022. The main outcome was the detection of episodes of nonpersistence and nonadherence 6 months before they happened. Adherence was defined as the ratio between the time covered by a drug purchase and the time between 2 purchases; patients were considered nonadherent if the ratio of their next 3 purchases was less than 80%. Disparities in persistence and adherence based on criteria such as age, treatment type, and income were identified. A total of 229 695 female patients (median [IQR] age, 63 [52-72] years) with localized breast cancer were included. A deep learning model based on a gated-recurrent unit architecture was used to detect episodes of nonpersistence or nonadherence. This model demonstrated an area under the receiving operating curve of 0.71 for persistence and 0.73 for adherence. Analyzing the Shapley Additive Explanations values also gave insights into the contribution of the different features over the model's decision. Patients older than 70 years, with past nonadherence, taking more than 1 treatment in the previous 3 months, and with low income had greater risk of episodes of nonpersistence. Age and past nonadherence, including regularity of past adherence, were also important features in the nonadherence model. This cohort study found associations of patient age and past adherence with nonpersistence or nonadherence. It also suggested that regular intervals in treatment purchases enhanced adherence, in contrast to irregular purchasing patterns. This research offers valuable tools for improving persistence of and adherence to oral anticancer treatment among patients with early breast cancer.

Why does hormonal contraception and menopausal hormonal treatment have such a small effect on breast cancer risk?

Oestrogen is considered by many to be a major cause of breast cancer, and yet hormonal contraception and menopausal hormonal therapy have a paradoxically small effect on breast cancer risk. Also, in the oestrogen-only arm of the Women's Health Initiative, subjects given oestrogen had a reduced risk of breast cancer compared to controls. Initiation of breast cancer likely begins early in life, in the long-lived ER-PR- breast stem cell. The main mitogen of ER+PR+ breast cancers is oestrogen derived from local breast fat and the tumour itself, rather than circulating oestrogens. Progesterone is relatively breast neutral, but progestins in the laboratory have been shown to expand malignant breast stem cell number.

Management of the axilla in breast cancer patients: critical review, regional modified Delphi consensus and implementation in the Tuscan breast network.

Data from recently trials have provided practice-changing recommendations in management of the axilla in early breast cancer (eBC). However, further controversies have been raised, resulting in heterogeneous diffusion of these recommendations. Our purpose was to obtain a better homogeneity. In 2021, the Tuscan Breast Network (TBN) established a consensus with the aim to update recommendations in this area. We performed a literature review on axillary management in eBC patients which led to an expert Delphi consensus aiming to explore the gray areas, build consensus and propose evidence-based suggestions for an appropriate management. Thereafter, we investigate their implementation in clinical practice. (1) DCIS patients should have SLN biopsy only in case of mastectomy or in conservative surgery if tumor is in a location that would preclude future nodal sampling or in case of a mass; (2) ALND may be omitted for 1-2 positive SLN patients undergoing BCS in T1-2 tumors with 1-2 SLN positive, eligible for whole-breast irradiation and adjuvant systemic therapies; (3) consider the option of RNI in patients with 1-3 positive lymph nodes and one or more high-risk characteristics; (4) the population identified in 2) should NOT undergo lymph node irradiation as an alternative to axillary surgery and (5) patients with clinically (pre-operatively) positive axilla, or undergoing primary systemic therapy, or outside the criteria reported in 2) must receive additional ALND and/or RT as per local policy. This consensus provided a practical tool to stimulate local and national breast surgical and radiotherapy protocols.

Effect of hormonal therapy on bone mineral density of breast cancer women

Background: Aromatase inhibitor (AI) was received by breast cancer women with estrogen receptor-positive. The estrogen is the main stimulator for receptor-positive breast cancer cells development and growth, the adjuvant hormone ablation targeting estrogen can decrease the likelihood of cancer recurrence and prolong cancer-free survival. Objective: To determine the effect of this therapy on bone mineral density of women who received it. Patients and Methods: It was identified 100 women with local or regional breast cancer diagnosed and who received AI therapy in the January 2022 to February 2023 from Baqubah teaching hospital/Oncology Centre. It was used DEXA scan to determine the bone minerals density of 50 women after different years from receiving hormonal therapy and other 50 breast cancer women before receiving hormonal therapy. Results: It was shown that there is a significant difference (p<0.0001) in the spine and hip density of breast cancer women who received AIs compare with the bone density of other breast cancer women who did not receive it. Conclusion: It can conclude that Als plays an essential role for osteoporosis that reduce the quality of health and increase the risk of fraction in the breast cancer women.

Hyaluronic acid-oleylamine and chitosan-oleic acid conjugate-based hybrid nanoparticle delivery via. dissolving microneedles for enhanced treatment efficacy in localized breast cancer

Microneedle technology offers a minimally invasive treatment strategy to deliver chemotherapeutics to localized tumors. Amalgamating the surface functionalized nanoparticles with microneedle technology can potentially deliver drugs directly to tumors and subsequently target cancer cells via, overexpressed receptors on the cell surface, thereby enhancing the treatment efficacy while reducing side effects. Here, we report cetuximab anchored hyaluronic acid-oleylamine and chitosan-oleic acid-based hybrid nanoparticle (HA-OA/CS-OA NPT)-loaded dissolving microneedles (MN) for targeted delivery of cabazitaxel (CBT) in localized breast cancer tumor. The HA-OA/CS-OA NPT was characterized for their size, surface charge, morphology, physicochemical characteristics, drug release behavior, and in vitro anti-cancer efficacy. The HA-OA/CS-OA NPT were of ~125 nm size, showed enhanced cytotoxicity and cellular uptake, and elicited a superior apoptotic response against MDA-MB-231 cells. Subsequently, the morphology and physicochemical characteristics of HA-OA/CS-OA NPT-loaded MN were also evaluated. The fabricated microneedles were of ~550 μm height and showed loading of nanoparticles equivalent to ~250 μg of CBT. The ex vivo skin permeation study revealed fast dissolution of microneedles upon hydration, while the drug permeation across the skin exhibited ~4-fold improvement in comparison to free drug-loaded MN. In vivo studies performed on DMBA-induced breast cancer in female SD rats showed a marked reduction in tumor volume after administration of drug and nanoparticle-loaded microneedles in comparison to intravenous administration of free drug. However, the HA-OA/CS-OA NPT-MN showed the highest tumor reduction and survival rate, with the lowest body weight reduction in comparison to other treatment groups, indicating its superior efficacy and low systemic toxicity. Overall, the dissolving microneedle-mediated delivery of targeted nanoparticles loaded with chemotherapeutics offers a superior alternative to conventional intravenous chemotherapy.

Impact of Radiation Therapy Modalities on Loco-regional Control in Inflammatory Breast Cancer

In inflammatory breast cancer, radiation therapy intensification is considered a standard of care by some teams, although the level of evidence remains low. We sought to analyze the impact of radiation therapy modalities on the risk of loco-regional and distant relapse. This retrospective multicenter study included patients with localized inflammatory breast cancer treated between 2010 and 2017. Standard postmastectomy radiation therapy consisted of daily fractions to a total dose of 50 Gy equivalent without a boost or bolus, while intensified radiation therapy referred to the use of a boost or bolus. The cumulative incidence curves of locoregional and distant recurrence were displayed using the competing risk method. Of the 241 included patients, 165 were treated with standard and 76 with intensified radiation therapy. There was significantly more nodal involvement in the intensified group. With a median follow-up of 40 months postradiation therapy, there was no difference between standard versus intensified radiation therapy regarding the cumulative incidence of locoregional (P = .68) or distant recurrence (P = .29). At 5 years, the risks of locoregional and distant recurrence were 12.1% (95% CI, 7.5; 17.7) and 29.4% (95% CI, 21.8; 37.3) for patients treated with standard radiation therapy and 10.4% (95% CI, 4.4; 19.3) and 21.4% (95% CI, 12.6; 31.9) for those treated with intensified radiation therapy. In multivariate analyses, triple-negative subtype and absence of complete pathologic response were associated with a higher risk of loco-regional recurrence. Radiation therapy intensification had no significant impact on locoregional and distant recurrence. For patients with a non-complete pathologic response (n = 172, 71.7%), no significant differences were observed between the 2 groups for loco-regional (P = .80) and distant (P = .39) recurrence. Severe toxicity rates were similar in both groups. Contrary to other important series, this large retrospective multicentric study did not show a locoregional or distant control benefit of intensified radiation therapy. Pooled prospective studies and meta-analyses of intensified radiation therapy are warranted to endorse this approach.

Safety of the Breast Cancer Adjuvant Radiotherapy in Ataxia-Telangiectasia Mutated Variant Carriers.

The Ataxia-Telangiectasia Mutated (ATM) gene is implicated in DNA double-strand break repair. Controversies in clinical radiosensitivity remain known for monoallelic carriers of the ATM pathogenic variant (PV). An evaluation of the single-nucleotide polymorphism (SNP) rs1801516 (G-A) showed different results regarding late subcutaneous fibrosis after breast radiation therapy (RT). The main objective of this study was to evaluate acute and late toxicities in carriers of a rare ATM PV or predicted PV and in carriers of minor allele A of rs1801516 facing breast RT. Fifty women with localized breast cancer treated with adjuvant RT between 2000 and 2014 at Institut Curie were selected. Acute and late toxicities in carriers of a rare PV or predicted PV (n= 9), in noncarriers (n = 41) and in carriers of SNP rs1801516 (G-A) (n = 8), were examined. The median age at diagnosis was 53 years old and 82% of patients had an invasive ductal carcinoma and 84% were at clinical stage I-IIB. With a median follow-up of 13 years, no significant difference between carriers and noncarriers was found for acute toxicities (p > 0.05). The same results were observed for late toxicities without an effect from the rs1801516 genotype on toxicities. No significant difference in acute or late toxicities was observed between rare ATM variant carriers and noncarriers after breast RT for localized breast cancer.