Treatment Of Early Breast Cancer Research Articles

Emergence of Quantum Dots as Innovative Tools for Early Diagnosis and Advanced Treatment of Breast Cancer.

Quantum dots (QDs) semiconducting nanomaterials, have garnered attention due to their distinctive properties, including small size, high luminescence, and biocompatibility. In the context of triple-negative breast cancer (TNBC), notorious for its resistance to conventional treatments, QDs exhibit promising potential for enhancing diagnostic imaging and providing targeted therapies. This review underscores recent advancements in the utilization of QDs in imaging techniques, such as fluorescence tomography and magnetic resonance imaging, aiming at the early and precise detection of tumors. Emphasis is placed on the significance of QD design, synthesis and functionalization processes as well as their use in innovative strategies for targeted drug delivery, capitalizing on their ability to selectively deliver therapeutic agents to cancer cells. As the research in this field advances rapidly, this review covers a classification of QDs according to their composition, the characterization techniques than can be used to determine their properties and, subsequently, emphasizes recent findings in the field of TNBC-targeting, highlighting the imperative need to address challenges, like potential toxicity or methodologies standardization. Collectively, the findings explored thus far suggest that QDs could pave the way for early diagnosis and effective therapy of TNBC, representing a significant stride toward precise and personalized strategies in treating TNBC.

Real-World Study of Adjuvant Biosimilar Trastuzumab-dkst for HER2-Positive Breast Cancer Treatment in a Brazilian Population.

Biological monoclonal antibodies play a pivotal role in cancer treatment, with biosimilars significantly enhancing their accessibility. In Brazil's ethnically diverse setting, real-world evidence is crucial for assessing the effectiveness and applicability of these therapies in routine clinical practice. We performed a multicentric, observational, prospective real-world study on biosimilar trastuzumab-dkst for adjuvant treatment of early HER2-positive breast cancer in Brazilian patients. Data were collected using a case-report form. Of the 176 recruited, we present data from the first 59 patients (mean age 51.7 ± 12.9years) who had completed treatment with trastuzumab-dkst. The mean time from diagnosis to the first adjuvant treatment with trastuzumab-dkst was 5.5 ± 2.7months. Of the patients, 59% of patients achieved at least a 30-month follow-up. The 31.7-month invasive disease-free survival rate (IDFS) was 94.5% (95% CI 83.9-98.2%) and median IDFS was not achieved, since only three patients had invasive disease recurrence. The overall survival rate was 100% until the last assessment. The observed adverse events were similar to those presented by other studies using biosimilar or reference trastuzumab. Four serious adverse events (8.5%) were observed. A reduction in left ventricular ejection fraction of at least 10% was observed in 16.9% of participants. There was no treatment interruption, and three participants (5.1%) had their trastuzumab-dkst dose reduced. Our study reinforces the existing pivotal data, underscoring the real-world efficacy and safety of biosimilar trastuzumab-dkst in the adjuvant treatment for early HER2-positive breast cancer. The preliminary long-term effectiveness and safety data we present further validate trastuzumab-dkst's role as a cost-saving alternative in oncological care. These findings have important implications for improving patient access to crucial treatments and for the more efficient use of healthcare resources. NCT03892655.

RNA-Seq based gene expression profiling of baseline and on-treatment breast tumors to predict response to HER2-directed therapy, without chemotherapy (TBCRC026).

530 Background: Robust biomarkers are needed to personalize treatment in early stage HER2-positive breast cancer. The TBCRC026 trial (n=83) demonstrated that early metabolic changes on FDG-PET/CT [>40% decline in SULmax at day 15 post treatment initiation (C1D15); C1D15 SULmax] were associated with response to neoadjuvant trastuzumab/pertuzumab (HP), without chemotherapy, in an ER-negative, HER2-positive cohort (NCT01937117). We investigated the association of RNA sequencing (RNAseq)-based gene expression signatures (GES) at baseline and on-treatment (C1D15), with early metabolic change on PET/CT and clinical outcomes. Methods: RNAseq (664 GES) was performed on baseline (n=56) and C1D15 (n=31) tumor biopsies (25 paired samples available). Association with pCR following HP (secondary), PET/CT parameters and survival (exploratory) was studied. Gene expression changes between baseline and C1D15 samples were tested by Wilcoxon signed-rank test. Association between GES and PET/CT parameters and GES with pCR were evaluated using logistic regression models. Cox regressions were performed to study the association between PET/CT SULmax at C1D15 and a B cell signature and relapse-free survival (RFS). The likelihood ratio test was used to compare the prognostic ability of two nested Cox models. Results: Both RNAseq and clinical outcomes were available in 53/83 patients. HER2-enriched (HER2-E) intrinsic subtype comprised 71% (40/56) of cases at baseline and 61% (19/31) at D15; basal subtype for 27% (15/56) and 39% (12/31), respectively. pCR rate was 19% (10/53) with all but one exhibiting HER2-E subtype. One basal-like sample underwent pCR, with downregulation of HER2 amplicon and IgG signatures slightly more prominent. Gene expression changes from baseline to C1D15 were analyzed; ERBB2was downregulated after HP (p = 0.007), B cell signatures, CD4, CD8, natural killer cells and Treg cells were significantly upregulated at C1D15. GES associated with 40% decline in SULmax at C1D15 included ERBB2 amplicon genes ( ERBB2, GRB7) and correlation to the HER2-E subtype, whereas basal-like signatures were significantly associated with lack of response on PET at C1D15. Univariate logistic regression analysis suggested that FOS-JUN, fibroblast and B cell GES at baseline were significantly associated with pCR (p=<0.05). Finally, the addition of a B cell signature improved the prognostic value of C1D15 SULmax on PET/CT for RFS (p < 0.05). Conclusions: In this unique cohort with ER-negative, HER2-positive breast cancer treated with neoadjuvant HP without chemotherapy, HER2-E tumors and those with increased immune signaling were more likely to respond to HER2-directed therapy. Combining C1D15 SULmax on PET/CT and a B cell signature provided improved prognostic information and should be further explored as candidate biomarkers in this setting. Clinical trial information: NCT01937117 .

Toxicity differences in CDK 4/6 inhibitors seen in Asian and Pacific Islanders.

e13086 Background: Cyclin-dependent kinases (CDK) 4/6 inhibitors are the standard of care, first line treatment for hormone receptor positive metastatic breast cancer and adjuvant high-risk hormone receptor positive early stage breast cancer along with endocrine therapy. There have been multiple clinical trials validating the effectiveness, along with toxicities of these agents; however, the majority of these trials lack ethnic diversity. This shortcoming limits the ability to apply these findings in diverse patient populations, especially among Asian and Pacific Islanders in Hawaii. Objective: To determine if the toxicity profile of CDK 4/6 inhibitors in women with breast cancer is different among patients at a community oncology practice in Hawaii, in which the majority of patients are Asian, Pacific Islander or a combination of both when compared to three landmark trials. Methods: A retrospective analysis of thirty-two patients with hormone receptor positive, HER2 negative metastatic or high risk breast cancer who started endocrine therapy and CDK 4/6 inhibitor therapy (abemaciclib, ribociclib, or palbociclib) between 2018-2023. Graded toxicities of each individual patient based on CTCAE criteria V. 5, along with demographic data was reviewed and compared to three main registration trials for these agents (MONARCH-3, MONALEESA-2, PALOMA-2). Results: Combined results from the three large randomized trials reported an average of 75% of participants were Caucasian, as compared to 15% in the Hawaii data. While 19% percent of participants from the combined large randomized trials reported being of Asian descent, none of these trials reported a breakdown of Asians versus Pacific Islanders. In the Hawaii sample, 41% were reported as Pacific Islander and 41% reported as Asian, 15% Caucasian, with the final 3% reported as Hispanic. Collective analysis of the FDA registration trials contained 0% Pacific Islander, 19.8% Asian, 74.3% White, 1.5% Black, and 4.4% Other. The majority of all toxicities of all grades were higher in the Hawaii population as compared to the three national trials, except for neutropenia with ribociclib and diarrhea with palbociclib (Table). Conclusions: The Hawaii analysis that was primarily comprised of Asians and Pacific Islanders revealed an increased incidence of toxicities, despite starting at lower doses rates for all CDK 4/6 inhibitors. This data analysis begins to highlight the importance of representative populations in clinical trials for the most effective and safest care of diverse populations. [Table: see text]

The role of obesity in the clinicopathologic variables and treatment of early stage breast cancer.

e12555 Background: Breast cancer (BC) is the second most common cancer among women in the United States. Studies have found obesity to be a key risk factor for BC, in which obese patients have higher recurrence and mortality. With 40% of the United State population being obese, we studied the differences in clinicopathological variables and treatment of normal-weight (NW) and obese patients with BC in a community-based cancer center within Florida. Methods: In this retrospective study, 535 patients with non-metastatic breast cancer (NMBC) diagnosed between January 1st, 2015 and December 31st, 2021 were identified. A Two Proportion Z test was done to evaluate the association between body mass index (BMI) groups of NW (BMI <25) and obese (BMI >30) patients amongst several independent variables. Variables included are histology, grade, estrogen and progesterone receptor status (ER/PR), human epidermal growth factor receptor 2 (HER2) status, chemotherapy, and surgical modality. Results: Results demonstrated that only Grade 2 histology was statistically more prevalent in NW vs obese patients (p < 0.01). 218 patients underwent mastectomy with 54% in the obese BMI. 317 patients were treated with lumpectomy with 65% in the obese BMI. Of the 211 NW patients, 97% were HER2 negative or low compared to 96% in the obese group. Only 3% and 4% of patients were HER2 positive in NW and obese groups, respectively. Of the obese patients, 40% were treated with neoadjuvant/adjuvant chemotherapy compared to 33% of NW patients (p=0.05). Factors such as mean age, smoking status and other demographic information were not statistically different between the groups. Conclusions: This study demonstrates that obese NMBC patients required chemotherapy more often than NW patients and that histologic characteristics cannot explain this difference in treatment. Factors such as stage at diagnosis or BC prognostic scores may contribute to the increased use of chemotherapy in obese patients. A limitation of this study is that the stage of disease at diagnosis was not abstracted, as a new staging system for BC was implemented in 2018. Furthermore, studies have suggested that, in obese patients, difficulty in identification of a mass in clinical or self -breast exam and poor compliance with screening guidelines may delay diagnosis of BC at an earlier stage. Obesity has many negative health effects, and with the increased use of novel weight loss medications, it will be important in the future to study the impact this may have on breast cancer development, histopathologic features, and treatment of patients with breast cancer. [Table: see text]

PARPi eligibility amongst women with newly diagnosed invasive breast cancer enrolled in the GREAT universal genetic testing study.

531 Background: Poly(ADP-ribose) polymerase inhibitors (PARPi) are approved for the treatment of BRCA-associated metastatic and high-risk early breast cancer. Recent guidelines have endorsed the use of BRCA1/2 testing for all patients with breast cancer who may be eligible for PARPi therapy, however it is unclear what proportion of patients are impacted by these recommendations. Methods: We sought to evaluate pre-test and post-test eligibility for PARPi in women aged >18 years old with a first diagnosis of stage I-IV invasive breast cancer who enrolled in a prospective, multicentered universal genetic testing study between 2019-2022. All enrolled patients underwent pre-test counselling and an obligatory primary panel of BRCA1, BRCA2, and PALB2 at the time of diagnosis. Candidacy for PARPi was determined by biologic subtype, clinical stage, pathologic stage, and/or response to neoadjuvant chemotherapy. Results: Of 1017 patients referred for the study, 805 were eligible and 729 (90.6%) consented to participate. The median age at diagnosis was 53 years (IQR, 45-62 years) and 96.2% had stage I-III disease. Overall, 32 (4.4%) patients had a germline pathogenic variant (GPV) in BRCA1/2, and 7 (1.0%) had a GPV in PALB2. Of 112 (15.4%) patients with triple negative breast cancer (TNBC), 19.6% had a GPV in BRCA1/2 or PALB2, whereas in 487 (66.8%) with ER+HER2- disease, 2.9% had a GPV (p<0.001). Among the 112 patients with TNBC, 64 (57%) were candidates for PARPi pre-genetic testing, and 12 (10.7%) remained eligible due to a GPV in BRCA1/2. Among the 487 patients with ER+HER2- breast cancer, 37 (5.1%) were candidates for PARPi pre-genetic testing, and 1 (0.2%) remained eligible due to a BRCA1 GPV identified on testing. All patients who were PARPi eligible were <65 years of age or >65 years with TNBC. Conclusions: In women with newly diagnosed invasive breast cancer, approximately 14% are candidates for PARPi prior to genetic testing, and 1.8% remain PARPi eligible due to a confirmed pathogenic variant in BRCA1/2. Consequently, genetic testing impacts systemic therapy decisions for PARPi in 10% of TNBC patients and fewer than 1% of women with ER+HER2- breast cancer. [Table: see text]

Systemic inflammatory markers in neoadjuvant pembrolizumab therapy for triple-negative breast cancer: Prognostic insights and nomogram construction.

e12649 Background: Systemic inflammatory markers derived from peripheral blood cells, such as the neutrophils and lymphocytes ratio (NLR), derived neutrophil lymphocyte ratio (dNLR), platelet-lymphocyte ratio (PLR), and lymphocyte–monocyte ratio (LMR), have shown promise as prognostic markers. Currently, neoadjuvant treatment (NACT) for early triple-negative breast cancer (eTNBC) involves the addition of an immune therapy, and little is known about the variation of these markers in this specific context. Methods: This study evaluated two groups who received NACT for eTNBC in a single third-level cancer center. The first received NACT with EC X4 and a weekly paclitaxel regimen, the second pembrolizumab and NACT. A total of 70 patients were included, 37 patients in the pembrolizumab group. NLR was defined as the absolute blood neutrophil count (N) divided by the absolute lymphocyte count (L), dNLR was defined as the N divided by the derived L (absolute leukocyte count — N), PLR was defined as the absolute platelet count divided by the L, LMR was defined as the L divided by the absolute monocyte count. Association between systemic inflammatory markers and pathological complete response (pCR) was analyzed using statistical tests. Inflammatory markers were evaluated at the time of diagnosis, at the time of chemotherapy regimen change, and 1 week before surgery. The χ2 test or Fisher’s exact test was used for correlation and Student’s t-test to compare different groups. Results: The pCR rates were 60,6% in the standard therapy and 77,8% in the pembrolizumab. There were no significant differences in clinical characteristics between the two groups. NLR, dNLR, PLR and LMR at 6 months showed significant differences compared to baseline levels. dNLR in the immunotherapy group, at the end of therapy, showed statistical significance with the Welch Two Sample t-test with p-value = 0.001. Variables were weighted with respect to the type of treatment and the outcome was assessed as pCR. On the basis of these data, a nomogram was constructed to predict the likelihood of achieving pCR in patients undergoing neoadjuvant pembrolizumab therapy. Conclusions: This study highlights the potential of systemic inflammatory markers as prognostic indicators in patients with eTNBC undergoing NACT. dNLR is a novel biomarker associated with clinical outcome in solid tumors. In this study, for the first time, a correlation was found between the use of pembrolizumab and the change in dNLR and consequently its impact on pCR. A nomogram was constructed to predict the outcome of pCR. [Table: see text]

Understanding Patient Experiences to Inform Future Studies to Optimize Personalization of Treatment for Early Breast Cancer.

Breast cancer treatment is multimodal, but not all patients benefit from each treatment, and many experience morbidities significantly impacting quality of life. There is increasing interest in tailoring breast cancer treatments to optimize oncological outcomes and reduce treatment burden, but it is vital that future trials focus on treatments that most impact patients. This study was designed to explore patient experiences of treatment to inform future research. An online survey was co-developed with patient advocates to explore respondents' experiences of breast cancer treatment. Questions included simple demographics, treatments received, and views regarding omitting treatments if that is deemed safe. The survey was circulated via social media and patient advocacy groups. Responses were summarized by using simple statistics; free text was analyzed thematically. Of the 235 participants completing the survey, 194 (82.6%) would choose to omit a specific treatment if safe to do so. The most commonly selected treatments were chemotherapy (n = 69, 35.6%) and endocrine therapy (n = 61, 31.4%) mainly due to side effects. Fewer respondents would choose to omit surgery (n = 40, 20.6%) or radiotherapy (n = 20, 10.3%). Several women commented that survival was their "absolute priority" and that high-quality evidence to support the safety of reducing treatment would be essential. Patients with breast cancer are individuals who may wish to optimize different components of their treatment. A portfolio of studies co-designed with patients is needed to establish an evidence base for greater treatment personalization with studies focused on reducing avoidable chemotherapy and endocrine therapy a priority.

Breast Conserving Surgery Post Neo-Adjuvant Chemotherapy for Locally Advanced Breast Carcinoma in a Developing Country: Is It Safe?

Breast conserving surgery (BCS) is the standard treatment for early breast cancer and has similar survival with mastectomy. The role of BCS in locally advanced breast cancer (LABC), post neoadjuvant chemotherapy (NACT), is controversial. Surgeons, especially in developing countries, fear higher margin involvement and local recurrence (LR) in BCS. The aim of this study was to determine the LR in BCS compared to mastectomy in LABC post NACT and to ascertain the percentage of involved surgical margins following both methods of surgery. This was a retrospective study of breast cancer patients seen in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). All patients had NACT followed by either mastectomy or BCS. The patients with Her2 enriched carcinomas did not have access to targeted therapy (Trastuzumab or Pertuzumab). The patients with ill-defined tumours underwent ultrasound assessment in the surgical clinics. All had post-operative radiotherapy. All with ER or PR positive cancers were given Tamoxifen for a minimum of 5 years. This study demonstrated that BCS post NACT was safe to be performed in selected patients with LABC in a developing country.

Abstract GS02-05: Overview of Axillary Treatment in Early Breast Cancer: patient-level meta-analysis of long-term outcomes among 20,273 women in 29 randomised trials

Abstract Background: In early breast cancer, the optimal management of the axilla is uncertain. To better understand the long-term benefits and risks of different approaches, we undertook an individual patient data meta-analysis of randomised trials comparing varying types of axillary treatment. Methods: Information was available on 20,273 women in 29 trials of axillary surgery or axillary radiotherapy. The trial comparisons included in this overview are summarised in Table 1. Randomisation took place during 1958–2009. Median follow-up was 10.0 years (IQR 7.4–11.5). Findings: In the trials of more extensive versus less extensive axillary treatment, the rate ratios (RR) for locoregional recurrence varied by site (p=0.003), however, 82% of these locoregional recurrences (552/670) occurred either in the breast or were of unspecified location (Table 2). Considering locoregional recurrence at any site, there was little difference in the risk from more versus less axillary treatment (10-year risk 4.3% vs 4.7%; RR 0.90 95% CI 0.77–1.05; p = 0.20), even in women treated for node-positive disease (3.7% vs 3.6%; RR 1.01, 95% CI 0.74–1.36, p=0.97). There was, however, a substantial difference in lymphoedema for trials of more versus less axillary surgery (odds ratio (OR) 2.35, 95% CI 2.05–2.70; p< 0.00001) and for trials of axillary treatment (surgery or radiotherapy) compared with no further axillary treatment (OR 3.08, 95% CI 2.01–4.71; p< 0.00001). In the four trials comparing axillary node clearance to axillary radiotherapy, the risk of locoregional recurrence appeared to be somewhat reduced in women allocated to clearance (43 vs. 56 events, 10-year risk 4.4% vs. 6.9%; RR 0.64, 95% CI 0.43-0.96, p=0.03) whilst their risk of lymphoedema was increased (OR 1.79, 95% CI 1.42–2.27; p< 0.00001). The risks of distant recurrence, breast cancer, non-breast-cancer, or all-cause mortality did not differ significantly by extent of axillary treatment or when comparing axillary clearance to radiotherapy. Interpretation: This is the most comprehensive overview of axillary treatment to date. Less extensive surgery, such as sentinel lymph node biopsy, or using axillary radiotherapy, resulted in a substantial reduction in lymphoedema compared to axillary node clearance. While there was no evidence of a difference in locoregional recurrence, a moderate effect cannot be excluded. Funding: Cancer Research UK, British Heart Foundation, Medical Research Council Table 1: Summary of the trials of treatment of the axilla in early breast cancer that began prior to 2012. Table 2: Numbers of locoregional recurrences as first event and rate ratios in the trials of more versus less axillary treatment. Citation Format: Gurdeep Mannu, Graham Beake, Richard Berry, David Dodwell, Robert Hills, Paul McGale, Stewart Anderson, Ian Campbell, Armando E. Giuliano, Reshma Jagsi, Thorsten Kuehn, Rebecca Llewellyn-Bennett, Eleftherios Mamounas, Robert Mansel, Pascal Roy, Emiel Rutgers, Nisha Sharma, Sandra Swain, Jonas Bergh, On behalf of the EBCTCG. Overview of Axillary Treatment in Early Breast Cancer: patient-level meta-analysis of long-term outcomes among 20,273 women in 29 randomised trials [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 GS02-05.

Abstract PO3-16-06: Perceptions and experiences of patients and healthcare providers on genetic testing and treatment of early breast cancer: qualitative findings

Abstract Background: Olaparib is approved as adjuvant therapy for high-risk HER2-negative early breast cancer (eBC) patients with germline BRCA mutations (BRCAm). Understanding patients’ preferences for genetic testing and treatment in the context of shared decision-making is needed to support optimal care in eBC. This study elicited the perspectives of patients with eBC and healthcare providers (HCP) treating eBC regarding treatment decision-making, and drivers and barriers to BRCA testing. Methods: Semi-structured interviews were conducted in the United States from Jan-Feb 2023 with women (n=12) diagnosed with eBC from 2017-2021. Community and academic oncologists treating eBC (n=12) and genetic counselors (GCs; n=8) were also interviewed. Patients who were tested (n=7) and untested (n=5) for BRCAm were included. A content and thematic analysis was performed which identified key factors from the data; these analyses provided both a range and common responses that may influence BRCA testing and treatment decisions. Results: BRCA-tested patients considered testing beneficial. In choosing to receive testing, >50% of patients reported HCP recommendation (n=7) and the opportunity to have “all of the information” about their eBC (n=7) as strong influencers. Patients declined genetic testing noting fear around negative impact to their insurance coverage (n=2) or mental health (n=3), or if they did not have family who would benefit from the information. Cost did not strongly influence testing choice. In choosing a treatment, patients sought to maintain their quality of life (QoL) with fewer side effects while minimizing chance of recurrence. They expressed the dual goals of normalcy during treatment, including curtailing side effects that impact QoL, and returning to normalcy after treatment (n=7). Patients were willing to accept unpleasant side effects to have a more effective treatment if those side effects do not severely impact their QoL and the treatment is highly effective (n=9). Side effects that may lead to hospitalization were the least accepted as they disrupt normalcy. HCPs reported that patients eagerly accept testing and face minimal familial or access barriers to testing. HCPs observed that among their non-Medicare patients, testing is usually covered by insurance with minimal out-of-pocket costs, thus alleviating financial constraints observed in previous years. HCPs believe BRCA testing is driven by updated hereditary cancer testing guidelines (e.g., NCCN), lower testing costs, closer collaborations of physicians and genetic counselors, and greater awareness among patients. HCPs reported that they embrace patient-led decision-making in eBC, especially as it relates to patients with BRCAm considering additional prophylactic surgery, and GCs further emphasized patient autonomy. Oncologists mentioned that they discuss risk status starting at diagnosis and these conversations evolve over the patient journey as new information emerges. In HR+ eBC, oncologists offered most patients with BRCAm adjuvant olaparib, which they perceive as well tolerated. In triple-negative eBC, oncologists opted for neoadjuvant Keytruda regimen prior to considering adjuvant olaparib for gBRCAm patients. Conclusions: Patients value information that empowers them to achieve their goals of normalcy and remission that can be achieved by addressing QoL, side effects, and patients' goals of living “normally”. Though prior research highlighted insurance coverage and costs as significant barriers to BRCA testing, results from this study suggest that cost was not a major factor in testing decisions. Prior barriers to testing access have been mitigated making it more available and affordable than in the past, which could be broadly communicated to patients and HCPs to minimize misperception. Citation Format: Jagadeswara Earla, Emily Mulvihill, Josh Lankin, Lauren Howell, Alex Kissling, Weiyan Li, Jaime Mejia. Perceptions and experiences of patients and healthcare providers on genetic testing and treatment of early breast cancer: qualitative findings [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 PO3-16-06.

Abstract PO2-01-07: Real-world efficacy of dual HER2-blockade in combination with anthracycline-containing and anthracycline-free neoadjuvant treatment in early breast cancer (BC)

Abstract BACKGROUND: Neoadjuvant therapy with antiHER-2 blockade is the standard of care for HER-2 positive early BC. The objective of this treatment is tumor downstaging to increase resectability and pathological complete response (pCR), a reliable surrogate endpoint for survival. Adding Trastuzumab (T) to chemotherapy resulted in an improvement in pCR, however, resistance to this agent is common and the incorporation of Pertuzumab (P) to the neoadjuvant scene demonstrated an increase in pCR in the Peony (39.3% vs 21.8%) and Neosphere trials (45.8% vs 29%). Across all studies, pCR is even higher in patients (pts) with negative hormonal receptor (HR) status (50%-63%) (3, 4). Tryphaena and Berenice found low rates of cardiotoxicity with T-P combination. Recently, TRAIN-2 data showed that anthracyclines and platinum have a similar pCR (67% vs 68%), but febrile neutropenia and cardiotoxicity is higher in the anthracycline group, concluding that omitting this therapy might be a preferred approach in the presence of dual HER2 blockade. Our study investigated the pCR benefit of dual HER2 blockade with anthracyclines and platinum in HER2 positive early BC. METHODS: We conducted a retrospective, unicenter, observational study of pts, treated with neoadjuvant T-P plus chemotherapy, in HER-2 positive early BC, between April 2015 and December 2022 at University Hospital A Coruña (Spain). The primary endpoint was total pCR in breast and axila (tpCR: ypT0/is ypN0). Secondary endpoints were: association between clinicopatological characteristics and pCR; and between cardiotoxicity and treatment pattern. Statistical analyses were conducted with Statistical Package for the Social Science (SPSS). RESULTS: During the study period, from April 2015 to May 2022, 154 pts were enrrolled. The median age was 51,3 years [range 26 – 799 years], all patients were female. Infiltrating ductal carcinoma was present in 92.2% pts, and 5.8% were inflammatory BC. At diagnosis, 11.7%, 61.7% and 26.6% had stages I, II and III, respectively, and 51.3% revealed axillary node involvement. Among observed cases, 94 (61%) were positive HR; 68 (45%) had histological grade 2 and 83 (53.9%) histological grade 3 tumors; and 151 pts (99.3%) presented a ki-67 level >20%. HER2 by immunohistochemistry (IHC) resulted in 3+ for 133 pts (86.9%) and in 2+ for 20 pts (13.1%), all of them with positive result by in situ hybridation (ISH). P-T were mostly combined with anthracyclines (64.9%). tpCR rate was 50.6%, and it was not significantly different according chemotherapy approach. tpCR was significantly higher among HR negative tumours (73.3%) compared with HR positive (36.2%) (p= 0.001), and in HER2 positive 3+ (55.6%) compared with HER2 positive 2+ (15%) tumours (p= 0.001). Achievement of tpCR was not significantly associated with tumor size, stage, histological grade and ki-67 level. Breast pCR was higher than tpCR (54.2%). 13 pts (8.4%) presented recurrence disease, in 76.9% of cases was a metastatic relapse. Cardiotoxicity was low during all stages of treatment and was not significantly associated with chemotherapy pattern. CONCLUSIONS: Neoadjuvant T-P plus chemotherapy with either anthracyclines or platinum therapy, demonstrated same efficacy and cardiac safety in our real-world study. pCR rates are lower in positive HR and HER2 positive 2+, needing more investigation with combination strategies including hormonotherapy, Our results are similar to data from randomized trials and other real-world efficacy studies, but we need more follow-up to identify late cardiotoxicity by anthracyclines and recurrences in positive HR tumors. Citation Format: Beatriz Alonso de Castro, Cristina Reboredo, Lourdes Calvo, Maria-Eva Perez-Lopez, Martin Igor Gomez Randulfe Rodriguez, Sofia silva diaz, Iria Parajo Vazquez, Silvia Antolin Novoa. Real-world efficacy of dual HER2-blockade in combination with anthracycline-containing and anthracycline-free neoadjuvant treatment in early breast cancer (BC) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-01-07.

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 PO1-27-07: Is HER2-low a biologically distinct breast cancer (BC) subtype? Prognosis and pathological complete response rate after neoadjuvant treatment (NAT) in early breast cancer (BC) HER2 negative

Abstract Background: Overexpression of HER2 is a significant prognostic and predictive factor in early breast cancer. HER2 positive tumors are those scored by immunohistochemistry (IHC) 3+ or 2+ with amplification by in situ hybridization (ISH). These tumors may benefit from HER2-targeted treatment and additionally, in early HER2-positive BC, achieving a complete pathological response after neoadjuvant treatment improves patient survival. In recent years, new anti-HER2 antibody-drug conjugates have proven effective for HER2 low BC (defined as IHC score 1+ or 2+ not amplified) in the metastatic disease setting; however, in HER2-low early BC, studies testing novel anti-HER2 antibody-drug conjugates as neoadjuvant therapy (NAT) are ongoing. Currently, we don´t know exactly whether HER2 expression can influence the pathological response rate after NAT or disease-free survival (DFS) in these patients compared to HER2-zero (IHC 0). The aim of our study is to determine the impact on response rate to NAT and survival outcomes in early HER2-negative BC. Methods: We conducted a retrospective study in two hospitals in Andalucia, Spain. Patients with early HER2 negative BC treated with NAT from January 2015 to June 2022 were included. Patients were divided into HER2 low patients (IHC 1+ or 2+ not amplified) and HER2 0 (IHC 0). We collected clinical and pathological characteristics, pathological response rate using the Residual Cancer Burden (RCB) system where a complete pathological response (pCR) was defined as ypT0/ypTis and ypN0, and survival outcomes. The primary objective of the study was to analyze the pCR rate after NAT according to HER2 score, and secondary objectives were to assess disease-free survival and overall survival (DFS and OS rates). Results: 574 patients were included (100% women). 397 patients had hormone receptors (luminal BC) on these tumors, and 177 did not have them, i.e., triple-negative BC (TNBC). 225 patients were HER2-zero, and 312 patients were HER2-low (253/312 patients had luminal BC and 59/312 patients were TNBC). The pCR in HER2-low patients was 17.3% and 23.1% in HER2-zero patients (p=0.047). For luminal BC patients, the pCR was 16.7% in HER2-low tumors and 13.7% in HER2-zero tumors (p=0.29). Similarly, there was no difference in pCR rates in TNBC patients (45.8% in HER2-low and 53.8% in HER2-zero tumors, respectively, (p=0.958). The overall survival (OS) at 96 months was 88.7% (95% CI 85.6%-92%). Regarding survival outcomes, neither HER2 expression level was associated with higher 8-year DFS: 81.1% in HER2-low patients (95% CI 75.7%-86.8%) and 74.9% in HER2-zero patients (95% CI 62.3%-90.1%) p=0.64. There was no difference between histological subtypes at 8-years regarding DFS rate: 80.5% (95% CI 74.3%-87.2%) in luminal HER2-low patients and 76.3% (95% CI 60.8%-95.7%) in luminal HER2-zero patients, p=0.22; 83.8% in TNBC HER2-low (95% CI 74.5%-94.2%) and 77.5% in TNBC HER2-zero patients (95% CI 69.4%-86.6%) p=0.26. We also didn´t find significant differences in terms of OS. For HER2-low patients, the 8-year OS was 90.9% (95% CI 87%-94.9%) and for HER2-zero patients, it was 86.4% (95% CI 80.8%- 92.5%) p=0.46. There were also no differences in OS for different histological subgroups with an 8-year OS in luminal HER2-low breast cancer patients of 92.5% (95% CI 88%-96.7%) and 87% in HER2-zero (95% CI 78.9%-96.1%) p=0.91. In patients with triple-negative breast cancer phenotype, the OS was 84.2% for HER2-low (95% CI 74.5%-95.2%) and 85.3% for HER2-zero (95% CI 77.9%-93.4%) p=1. Conclusions: We found no difference in survival outcomes and response rate to conventional NAT between HER2-low and HER2-zero expression levels. Therefore, our data do not support the hypothesis of HER2-low as a biologically specific breast cancer subtype. Further research on this approach with HER2 antibody-drug conjugate schemes as an alternative to traditional NAT schemes is warranted. Citation Format: Ana Gil-Torralvo, Yeray Rodriguez, Alejandro Falcon, David Morales, Mónica Cejuela, Isabel Miras, Marta Amérigo, Manuel Ruíz - Borrego, Juan Bayo, Francisco Javier Salvador Bofill. Is HER2-low a biologically distinct breast cancer (BC) subtype? Prognosis and pathological complete response rate after neoadjuvant treatment (NAT) in early breast cancer (BC) HER2 negative [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 PO1-27-07.

Abstract PO5-26-06: Understanding patient experiences to inform future studies to reduce treatment burden in breast cancer

Abstract Background Most patients with early breast cancer receive multimodality therapy, including surgery, chemotherapy, radiotherapy and endocrine therapy. Currently, not all patients benefit from the treatments they receive but many experience significant morbidities that substantially impact their quality of life. Personalised approaches to treatment offer the opportunity for patients to avoid treatments that do not offer oncological benefit without compromising breast cancer outcomes. Further studies are needed to evaluate these approaches; it is vital that future research is designed to optimise treatment benefit while remaining acceptable to patients. This survey aimed to understand experiences of patients who have received treatment for early breast cancer to inform future risk-adapted studies. Methods An online survey was co-developed with patient advocates to explore respondents’ experiences of treatments. Questions included simple demographics, treatments received and views about omitting therapies if it was safe to do so. Free-text boxes were provided for respondents to explain their decision. The survey was circulated via social media platforms from April-July 2023. Responses were summarised using simple descriptive statistics and free text was analysed thematically. Results 112 responses were received. Respondents were mostly aged 40-60 (n=88, 72.7%) and diagnosed with breast cancer between 1995 - 2023 (median 2017). Treatments received included surgery (n=107, 95.5%), radiotherapy (n=85, 75.9%), chemotherapy (n=69, 61.6%) and endocrine therapy (n=82, 73.2%). Of the 106 (94.6%) respondents who expressed a preference, 38 (35.8%) would omit chemotherapy; 34 (32.1%) would choose not to have endocrine therapy; 19 (17.9%) would prefer to avoid surgery and 11 (10.4%) would omit radiotherapy if safe to do so. Respondents opting to avoid chemotherapy highlighted the ‘brutal’ short-term side effects and their profound impact on their ability to continue with their daily lives. Hair loss was a common concern and chemotherapy was considered ‘very visible’, making them a ‘cancer patient’ in the eyes of others. Long-term effects of treatment such as peripheral neuropathy had lasting effects on respondents’ activities of daily living. Almost all respondents who would omit endocrine therapy cited the profound impact of side effects including joint/muscle pains, fatigue, hair loss, sleep disturbance and loss of libido on quality of life. Some respondents commented that the treatment itself was a daily reminder of their diagnosis. Surgery was identified as having long-term impacts on respondents’ physical and psychological well-being. Many expressed a desire to avoid ‘disfiguring’ procedures which had affected their relationships and quality of life. Respondents highlighted specific procedures they would choose to avoid including mastectomy due to the ‘trauma’ of losing a breast and axillary node clearance due to complications such as lymphoedema. Fewer women chose to avoid radiotherapy. Reasons to do so included both short and long-term side effects of treatment including chronic pain, difficulties travelling and attending for treatment over 5 weeks. Although there was generally a positive response to the concept of reducing unnecessary treatments, safety was a key concern. Several respondents commented that they would have any treatments considered necessary as survival was their ‘absolute priority’. Respondents felt that patients would need to be reassured that any reduction in treatment would not impact long-term outcomes. Conclusions This survey suggests patients would support studies aiming to reduce the burden of breast cancer treatment, and that different patients may wish to de-escalate different components of therapy. Studies developing an evidence base to allow treatment personalisation with a particular emphasis on reducing chemotherapy and endocrine therapy are research priorities. Citation Format: Shelley Potter, Mhairi MacTier, Katherine Fairhurst, Jacqui Gath, Hilary Stobart, Stuart McIntosh. Understanding patient experiences to inform future studies to reduce treatment burden 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 PO5-26-06.

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 PO3-28-05: Therapeutic Plasmapheresis as a Symptomatic Treatment for Paclitaxel-Associated Peripheral Polyneuropathy

Abstract Relevance: Paclitaxel-associated peripheral polyneuropathy (PIPN) is one of the most common side effects that develop during treatment with drugs of the taxane group. In the treatment of early breast cancer with paclitaxel 80 mg/m2 weekly, 12 injections, PINP develops in 90% of patients of varying severity. The main symptoms are pain and numbness in the arms and legs, which is associated with the accumulation of paclitaxel in the ganglia of the spinal cord, as well as increased expression in the ganglia of the spinal cord of chemokines and cytokines, such as IL-1β, IL-8 and TNF-α, as well as CXCR4, RAGE, CXCL1, CXCL12, CX3CL1 and C3. We hypothesized that the severity of PIPN symptoms can be reduced by lowering the concentration of chemokines and cytokines in the blood by performing plasmapheresis sessions. Research methods: An open prospective study was carried out, the protocol of which was approved by the ethical committee. The study included 30 patients (100% women) aged 30 to 60 years (mean age 45 years) who developed PIPN during paclitaxel therapy 80 mg/m2, weekly, 12 injections. The severity of PIPN symptoms was assessed using a “visual analogue scale” (VAS). The results of the VAS evaluation varied from 6 to 8 points. Patients underwent 5 courses of membrane plasmapheresis with exfusion of 400-500 ml of plasma per session (20 ml per 1 kg of body weight), plasma loss was compensated with saline. Repeated procedures were performed once every two months for 6 months. Results: 30 patients underwent 15 procedures of therapeutic plasmapheresis within 6 months. In 21 patients (70%) there was a pronounced decrease in PIPN symptoms (VAS - 2-3 points), in 3 patients (10%) a moderate decrease in symptoms (VAS -5-6 points), in 6 (20%) no effect of plasmapheresis (VAS - 7-8 points). Approximately 15% of procedures were associated with adverse events, the most common of which were vasovagal reactions; 20% of patients had at least one adverse event. Conclusions: Given the subjective reduction in the severity of PIPN symptoms during courses of therapeutic plasmapheresis in more than 70% of cases, therapeutic plasmapheresis can be used as a symptomatic therapy for PIPN, however, taking into account the subjective assessment of the results by patients, there may be a risk of developing cognitive errors. Therefore, this method of therapy requires more thorough study. Citation Format: Sardor Abdugafforov, Vladimir Vorotnikov, Alexander Soynov, Tornike Mchedlidze, Igor Kopytich, Sofia Kim. Therapeutic Plasmapheresis as a Symptomatic Treatment for Paclitaxel-Associated Peripheral Polyneuropathy [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 PO3-28-05.

Abstract GS03-02: Mammographic surveillance in early breast cancer patients aged 50 years or over: results of the Mammo-50 non-inferiority trial of annual versus less frequent mammography

Abstract Introduction: Annual surveillance mammograms for an unspecified period, after treatment for early breast cancer, are widely practised in USA and Europe and represent a significant healthcare cost. Current UK guidelines recommend annual mammograms up to 5 years, then reverts to 3 year screening without specified risk stratification. Further evidence is needed to determine the optimum frequency and duration of mammographic surveillance. Methods: A multi-centre, randomised controlled, phase III trial of annual mammography versus 2-yearly for conservation surgery and 3-yearly mammograms for mastectomy patients up to 9 years. Women were eligible if aged 50 years or over at initial diagnosis of breast cancer (invasive or DCIS), and recurrence free 3 years post curative surgery. Primary outcome was breast cancer specific survival (BCSS). Secondary outcomes include recurrence free interval (RFI) and overall survival (OS). BCSS event was defined as deaths from breast cancer and RFI as any locoregional or distant invasive recurrence or new breast primary. 5000 women were needed to detect a 3% absolute non-inferiority (NI) margin for BCSS with 2.5% one-sided alpha and at least 85% power. Analyses were carried out on intention-to-treat basis. Results: 5235 women were randomised between April 2014 and September 2018. 4347 (83%) women were aged 55-75 years, 4203 (80%) had undergone conservation surgery, 4564 (87%) had invasive disease, 1162 (22%) had node positive disease, 4330 (83%) had ER positive tumours and 3812 (73%) were taking hormone therapy at the time of randomisation. Patient characteristics were balanced across arms. With a median of 5.4 years follow-up (interquartile range 4.6-5.9), 319 women have died; 104 of breast cancer (53 on annual arm; 51 on less frequent arm). BCSS at 5 years was 98.2% (95% CI 97.5-98.6%) on annual arm and 98.3% (95% CI 97.7-98.8%) on less frequent arm. Hazard ratio (HR) was 1.04 (95% CI 0.71 -1.54), demonstrating non-inferiority of less frequent mammograms at the 3% margin (NI p< 0.0001; critical value 2.71) and the 1% margin (NI p=0.02; critical value 1.56). 320 (6%) women had a new invasive breast cancer event (55 loco-regional recurrences, 85 new breast primaries, 139 distant recurrences and 41 with multiple invasive events); 164 on the annual arm compared to 156 on the less frequent arm. Five-year RFI was 94.2% (95% CI 93.2-95.1%) for the annual arm and 94.4% (95% CI 93.4-95.3%) for the less frequent arm; HR= 1.03; (95% CI 0.83-1.28) demonstrating non-inferiority at a 2% margin (NI p=0.006; critical value 1.36). OS at 5 years was 94.9% (95% CI 93.9-95.7%) on the annual arm and 94.3% (95% CI 93.3-95.2%) on the less frequent arm. Hazard ratio (HR) was 1.18 (95% CI 0.94 -1.47), demonstrating non-inferiority of less frequent mammograms at the 3% margin (NI p=0.003; critical value 1.61) and the 2.5% margin (NI p=0.02; critical value 1.51). A total of 14987 mammograms have been performed on the annual arm and 8047 on the less frequent arm. 1967 (75%) of 2618 women on the annual arm complied with their allocated schedule compared to 1775 (68%) of 2617 women on the less frequent arm. COVID-19 pandemic affected compliance; it is estimated that 345 (7%) women missed mammograms during the pandemic. A sensitivity analysis was performed on the 72% of women who fully complied with their scheduled mammograms as per protocol, and again NI was demonstrated for BCSS, RFI and OS. Conclusions: For patients aged 50 or older and 3 years post diagnosis, Mammo-50 demonstrated that less frequent mammograms were no worse than annual mammograms. These results provide evidence for less frequent mammographic surveillance for this patient population. Citation Format: Janet Dunn, Peter Donnelly, Nada Elbeltagi, Andrea Marshall, Alastair Thompson, Riccardo Audisio, Sarah Pinder, David Cameron, Amy Campbell, Sue Hartup, Lesley Turner, Annie Young, Helen Higgins, Eila Watson, Sophie Gasson, Peter Barrett-Lee, Claire Hulme, Bethany Shinkins, Peter Hall, Andy Evans. Mammographic surveillance in early breast cancer patients aged 50 years or over: results of the Mammo-50 non-inferiority trial of annual versus less frequent mammography [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 GS03-02.

Abstract PO2-09-12: The magnitude and temporal variations of socioeconomic inequalities in quality of life after early breast cancer: results from the multicentric French CANTO cohort

Abstract Objective Previous studies showed that various outcomes in patients with early breast cancer (EBC), from incidence to survival, were influenced by social factors. However, there is limited research on the socioeconomic inequalities in quality of life (QoL) after treatment for EBC, and the magnitude and changes over time of these inequalities have not been quantified. This study examines the socioeconomic inequalities in QoL and their time trends among a large cohort of patients with EBC. Methods We conducted a comprehensive longitudinal analysis using data from the prospective multicentric CANTO study (CANcer TOxicity, NCT01993498), which included participants with EBC enrolled between 2012 and 2018. QoL was assessed using the summary score of the EORTC QLQ-C30 questionnaire at the time of diagnosis and 1 and 2 years post-diagnosis. We included patients with complete QoL data at diagnosis and 2 years post-diagnosis. Analyses were conducted for three indicators of socioeconomic status separately: self-reported financial difficulties, household income and educational level. We first analyzed trajectories of QoL by socioeconomic status from diagnosis to Year 1 and Year 2. Then, social inequalities in QoL were estimated using the regression-based slope indexes of inequality (SII) and compared across the follow-up periods. The SII represents the absolute change in the QLQ-C30 summary score along the two extremes of the socioeconomic gradient, taking into account the intermediate groups and their relative sizes. The analyses were adjusted for age at diagnosis, Charlson comorbidity index, disease stage, use and type of endocrine therapy, use and type of chemotherapy, breast surgery, radiotherapy use, and lymph node management. Results In the 5915 analyzed patients, compared to those with higher socioeconomic status, those reporting a high level of financial difficulty, lower income, or lower education were younger, most often premenopausal, with comorbidities, diagnosed with stage III BC, and treated with mastectomy and axillary lymph node dissection. There were no differences between socioeconomically-defined groups concerning BC histology, grade and IHC-defined subtype. Social inequalities in QoL at baseline were statistically significant for all socioeconomic status indicators (SIIfinancial difficulties = -7.6 [-8.9;-6.2], SIIincome= -4.0 [-5.2;-2.8]) and SIIeducation= -1.9 [-3.1;-0.7]). In multivariable analyses, social inequalities significantly increased (interaction p< 0.05) in Year 1 (SIIfinancial difficulties = -11.1 [-12.8;-9.4], SIIincome= -6.5 [-8.0;-5.0] and SIIeducation= -5.0 [-6.6;-3.5]) and Year 2 (SIIfinancial difficulties = -10.7 [-12.2;-9.1], SIIincome= -6.7 [-8.0;-5.3] and SIIeducation= -4.7 [-6.1;-3.3]) suggesting a widening socioeconomic gap in QoL outcomes irrespective of pre-diagnosis health, tumor characteristics and treatment. Similar results were observed in subgroups defined by menopausal status (pre/postmenopausal) and type of systemic treatment (chemotherapy, endocrine therapy). Conclusion Our study highlights and quantifies the association of several individual socioeconomic indicators with the QoL of patients with EBC in France. The magnitude of socioeconomic inequalities in QoL increased over time after EBC diagnosis in a country with a strong welfare system and universal healthcare coverage. In the era of precision medicine, these results underscore the importance of developing interventions to improve precision care, considering the conditions in which people are born, grow, work, live and age and the wider set of forces and systems shaping the conditions of daily life. Citation Format: José Luis Sandoval, Antonio Di Meglio, Arlindo Ferreira, Maria Alice Franzoi, Fabrice André, Barbara Pistilli, Christelle Jouannaud, Marion Fournier, Philippe Rouanet, Asma Dhaini Mermeche, Paul Cottu, Sibille Everhard, Anne-Laure Martin, Silvia Stringhini, Idris Guessous, Ines Vaz Luis, Gwenn Menvielle. The magnitude and temporal variations of socioeconomic inequalities in quality of life after early breast cancer: results from the multicentric French CANTO cohort [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 PO2-09-12.

Abstract PO5-19-01: The HER2-RADiCAL study (Response ADaptive CAre pLan) – Tailoring treatment for HER2 positive early breast cancer

Abstract Background The presence or absence of residual disease following neoadjuvant systemic anti-cancer therapy (neoSACT) for HER2-positive early breast cancer (HER2+ EBC) provides powerful prognostic information. Pathological complete response (pCR) following neoSACT, particularly in patients with earlier clinical TNM stage at diagnosis, identifies a population with excellent survival outcomes in whom the balance of toxicity associated with the current treatment pathway may be disproportionate to absolute clinical benefit. Aims >HER2-RADiCAL seeks to reduce the treatment burden and healthcare costs of treating HER2+ EBC by testing the hypothesis that pCR can be used as a functional response biomarker to select patients who can safely receive less systemic therapy with minimal/no loss of efficacy. Trial design and eligibility criteria HER2-RADiCAL is a response-directed interventional cohort/threshold-crossing design study embedded within a real-world data-driven clinical pathway model. Patients with ER-positive or negative HER2+ EBC with cT1N1 or cT2N0-1 stage at diagnosis are eligible after completion of standard of care neoSACT and locally determined pCR (ypT0/Tis ypN0). Patients with pathological features consistent with previous malignant involvement in >4 nodes are not eligible. Adjuvant trastuzumab +/- pertuzumab may have continued prior to study entry provided no more than 9 cycles of trastuzumab are received. After registration all participants receive a total of 9 cycles of trastuzumab including those administered prior to study entry. Participants receive no further pertuzumab and no adjuvant chemotherapy. Adjuvant endocrine therapy and radiotherapy are given as per standard of care. Central pathology review of pCR status will be conducted in a subset of cases. A Study Within a Trial (SWAT) will explore identification of factors influencing patient decision-making for participation in studies of response-adapted treatment. Statistical methods The primary endpoint is relapse-free interval. Recruitment of 720 participants over 3.5 years will provide 90% power to exclude an event rate >6.5% at 3 years (expected event rate ≤4%). Secondary endpoints include relapse-free survival, invasive breast cancer-free survival, invasive disease-free survival, distant recurrence-free interval, breast cancer-free interval, overall survival, treatment pathway adherence and cost-effectiveness. An interventional cohort is preferred to a randomised non-inferiority trial based on the known event rate in this population which is sufficiently low such that any deviation from this expected event rate would indicate failure of the reduced therapy strategy. Real-world data driven clinical pathway model Health economic modelling will compare the protocol-driven study cohort with two comparator pathways: a non-response adapted maximum therapy pathway (the standard clinical pathway prior to the study) and a real-world representative pathway derived from anonymised data for all patients treated for HER2+ EBC within the UK NHS. Patient and public involvement Our PPI partners continue to shape this research, holding key roles as trial management group members, overseeing progress of the study, contributing to protocol amendment development, and design and implementation of the SWAT. Current status The first patient was enrolled in December 2021. At 10th July 2023, 25 research sites have opened with 39 participants recruited. Site opening continues with a minimum target of 40. Responding to continued use of anthracycline-based regimens in UK practice, eligibility criteria have recently been extended to permit entry of patients who have received anthracycline-containing neoSACT. For further information contact her2radical-icrctsu@icr.ac.uk. Citation Format: Iain Macpherson, Stuart McIntosh, Lucy Kilburn, Holly Tovey, Laura Moretti, Katie Goddard, Indrani Bhattacharya, Clinton Boyd, Cliona Kirwan, Ciara O'Brien, Duncan Wheatley, Jennifer Glendenning, Mairead MacKenzie, Hilary Stobart, Claire Snowdon, Andrew Wardley, Abeer Shaaban, Peter Hall, David Cameron, Judith Bliss. The HER2-RADiCAL study (Response ADaptive CAre pLan) – Tailoring treatment for HER2 positive early 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 PO5-19-01.