Node-positive Early Breast Cancer Research Articles

Evaluating Magnetic Seed Localization in Targeted Axillary Dissection for Node-Positive Early Breast Cancer Patients Receiving Neoadjuvant Systemic Therapy: A Comprehensive Review and Pooled Analysis.

Background/Objectives: De-escalation of axillary surgery is made possible by advancements in both neoadjuvant systemic therapy (NST) and in localisation technology for breast lesions. Magseed®, developed in 2013 by Dr. Michael Douk of Cambridge, United Kingdom, is a wire-free localisation technology that facilitates the localisation and retrieval of lymph nodes for staging. Targeted axillary dissection (TAD), which entails marked lymph node biopsy (MLNB) and sentinel lymph node biopsy (SLNB), has emerged as the preferred method to assess residual disease in post-NST node-positive patients. This systematic review and pooled analysis evaluate the performance of Magseed® in TAD. Methods: The search was carried out in PubMed and Google Scholar. An assessment of localisation, retrieval rates, concordance between MLNB and SLNB, and pathological complete response (pCR) in clinically node-positive patients post NST was undertaken. Results: Nine studies spanning 494 patients and 497 procedures were identified, with a 100% successful deployment rate, a 94.2% (468/497) [95% confidence interval (CI), 93.7-94.7] localisation rate, a 98.8% (491/497) retrieval rate, and a 68.8% (247/359) [95% CI 65.6-72.0] concordance rate. pCR was observed in 47.9% (220/459) ) [95% CI 43.3-52.6] of cases. Subgroup analysis of studies reporting the pathological status of MLNB and SLNB separately revealed an FNR of 4.2% for MLNB and 17.6% for SLNB (p = 0.0013). Mean duration of implantation was 37 days (range: 0-188). Conclusions: These findings highlight magnetic seed localisation's efficacy in TAD for NST-treated node-positive patients, aiding in accurate axillary pCR identification and safe de-escalation of axillary surgery in excellent responders.

Abstract PO3-01-13: A study of the impact of the implementation of the Oncotype Dx 21-gene breast-cancer assay during the SARS-CoV-2 pandemic for 1-3 node positive early breast cancer: The Clatterbridge Cancer Centre Experience

Abstract Background: The 21-gene breast cancer (BC) assay (Oncotype Dx) is used to predict chemotherapy benefit in ER+, HER-2- lymph node (LN) negative BC. The RxPONDER trial demonstrated that post-menopausal patients with ER+, HER2- BC with 1-3 LN and a recurrence score (RS) of < 25 did not benefit from adjuvant chemotherapy. In response to the SARS-CoV-2 pandemic Oncotype Dx was implemented for ER+, HER2- 1-3 LN+ BC patients in Merseyside, UK (population 2.6 million) This study sought to understand the impact of this measure on clinical practice. Methods: All patients whose tumours were assessed with Oncotype Dx assay between Mar 20 - Nov 22 were identified through the Exact Sciences portal. Menopausal status, tumour characteristics, RS and chemotherapy regimen were recorded. The impact on cancer care was estimated using the number of infusions and clinic visits specified by our institution chemotherapy protocol for node positive disease. The financial impact was calculated using the test list price, estimated costs of adjuvant chemotherapy in the UK (Annals of Oncology, Volume 32, suppl 2 S46). The number of patients predicted to receive chemotherapy pre-oncotype DX was calculated using data from the UK PONDx trial data. Results: A total of 242 patients were tested over the 32 month period. Table 1 summarises the clinico-pathological characteristics including by RS score. The median age was 58.5 and 77.3% (n=187) were post-menopausal. The median tumour size was 25mm and median LNs with macrometastasis was 1. 198 (81.9%) patients had an RS < 25. Overall 73 patients (30%) received chemotherapy of which 34 had an RS < 25. Pre-menopausal patients were more likely to receive chemotherapy with RS < 25 than post-menopausal patients, 47.9% (23/48) vs 7.3% (11/150) respectively. In the absence of Oncotype Dx testing 169 patients would have received adjuvant chemotherapy. Therefore, 96 patients avoided chemotherapy. This equates to 1,620 chemotherapy infusions and 324 clinic attendances. The estimated cost saving was ~£50K. Conclusions: This real-world study demonstrates that the use of Oncotype DX assay for ER+,HER2- 1-3 LN+ early BC spared a significant number of patients chemotherapy during the SARS-CoV-2 pandemic, so avoiding the risk of adverse effects. This also resulted in benefits to the healthcare system with a reduction in scheduled cancer care and achieved financial savings. This, therefore, demonstrates the benefit of using the Oncotype Dx assay. Table 1: Clinico-pathological information Citation Format: Alexandra Johnson, Sonia Bathla, Leena Chagla, Joanne Cliff, Allison Hall, Anita Hargreaves, Clare Hart, Zafar Malik, Chandeena Roshanlall, Raj Sripadam, Carlo Palmieri, Helen Innes. A study of the impact of the implementation of the Oncotype Dx 21-gene breast-cancer assay during the SARS-CoV-2 pandemic for 1-3 node positive early breast cancer: The Clatterbridge Cancer Centre 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 PO3-01-13.

Abstract PO3-23-07: Evaluation of the role of axillary ultrasound to estimate axillary nodal burden to guide de-escalation of upfront axillary surgery in node positive early breast cancer patients

Abstract Background: Axillary surgery is now routinely de-escalated in clinically node negative breast cancer patients with limited axillary nodal burden (up to 2 involved sentinel nodes) based on the results of ACOSOG-Z0011 and AMAROS trials. However, patients with proven axillary metastasis following on ultrasound (AUS) guided core needle biopsy (CNB), undergoing primary surgery are still subjected to an axillary lymph node dissection (ALND) irrespective of the magnitude of the axillary nodal burden. If we could predict axillary nodal burden with a low false negative rate (FNR) for the presence of extensive axillary nodal involvement, we can then hypothesize that axillary surgery could be safely de-escalated in this cohort of patients. We investigated whether pre-operative AUS suggesting limited axillary burden is sensitive enough to rule out gross axillary disease burden. Methods: A single institution retrospective study. We undertook an electronic chart review of all T1 to T3 patients undergoing upfront ALND with either mastectomy or breast conserving surgery between January 2019 and June 2023. Patients with palpable axillary nodes, locally advanced breast cancer or a completion ALND after positive sentinel lymph node biopsy (SLNB) were excluded from the study. Clinical and pathological characteristics associated with nodal burden of disease were evaluated. Limited axillary burden was defined as < 2 involved nodes with ≥3 taken as gross nodal burden for primary analyses. Sensitivity analyses were carried out with limited axillary burden defined as < 3 involved nodes (N1) and ≥4 (N2) taken as gross nodal burden. Subgroup analyses in T1 or T2 tumors were carried out as well. The probabilities of discordant events, defined as limited burden on AUS-CNB but gross burden on final histopathology evaluation (HPE), assuming 10% FNR, were estimated using inverse cumulative binomial distribution function. Results: Data on the exact number of suspicious nodes on AUS were missing for 2 patients, therefore, the final study cohort included 39 patients. The correlation between AUS nodal burden and that on HPE was moderate (Spearman’s rho = 0.48; p = 0.0018). The sensitivity and specificity of AUS in identifying gross nodal burden were 61% and 81% respectively. Observation of 9 discordant events in 22 patients with low burden on AUS ruled out an FNR of < 10% with 99.99% certainty. The sensitivity and specificity in T1/T2 subgroup were 60% and 75% respectively. The sensitivity analyses classifying N1 as limited and N2 as gross axillary burden showed the sensitivity and specificity of 35% and 82% respectively and an FNR of < 10% was ruled out with 99.996% certainty. Conclusion: Pre-operative AUS alone lacks the sensitivity and specificity to accurately predict the true axillary nodal burden to safely guide de-escalation of axillary surgery. AUS followed by targeted axillary dissection (TAD) in conjunction with a dual technique SLNB may provide the desired sensitivity and specificity to guide de-escalation of axillary surgery. A prospective evaluation of this approach is merited. Given the limited number of patients that could be enrolled in such prospective study from individual institutions, an international collaborative effort is needed to address this important research question. Citation Format: Nidhi Garg, Mangesh Thorat, Hisham Hamed, Ashutosh Kothari. Evaluation of the role of axillary ultrasound to estimate axillary nodal burden to guide de-escalation of upfront axillary surgery in node positive early breast cancer patients [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 PO3-23-07.

Abstract PO1-14-05: A comparison of chemotherapy recommendations by NPI, Predict, and Oncotype DX testing in UK women with early node positive breast cancer

Abstract Introduction: Gene expression testing is expensive and, unless it changes the chemotherapy (CT) decision, unnecessary. Both Nottingham Prognostic Index (NPI) and Predict Breast Cancer (Predict) are free to use and based on clinico-pathological data. Each gives a guide to the prognosis. Many clinical teams in the UK have used these indices to guide treatment and more recently to help decide who should have access to gene expression testing. NPI scores of ≤2.4 have a cancer-specific ten-year survival of 96%, and >2.4 to ≤3.4, >3.4 to ≤5.4 and >5.4 have survivals of 93%, 78% and 44% respectively. UK oncologists use it as a guide in recommending adjuvant treatment. CT is not recommended for patients with NPI ≤3.4, is discussed as on option for NPI >3.4 to ≤5.4 and is recommended for NPI >5.4. Similarly, Predict can be used to guide CT decisions as follows: < 3% benefit, CT not recommended; 3-5% CT discussed as a possible option; >5% CT recommended. The OncotypeDX® Breast Recurrence Score® test has been assessed recently in the RxPONDER trial which concluded that postmenopausal women with a Recurrence Score (RS) result < 26 showed no benefit from the addition of CT. This study compares the clinical utility of three indices (NPI, Predict, and RS result) by assessing the distribution of NPI and Predict across RS result, evaluates changes in CT recommendations based on risk group, and by estimating the likelihood of CT recommendation. Methods: We recently conducted a prospective UK decision impact, decision conflict and economic analysis of Oncotype DX® test in early node positive, hormone receptor positive and HER2 negative breast cancer involving 664 women. Using these data, we calculated the NPI and the Predict score. Descriptive statistics, logistic regression and McNemar’s tests were used to assess the associations between NPI, Predict, RS result and change in CT decisions for all patients (n=664) and in the cohort of post-menopausal patients recruited after RxPONDER reported (n=176). Results: Table 1 shows similar stratification for all three indices within the low-risk groups, but not for the high-risk groups. Similar results were observed in the post-menopausal, post-RxPONDER cohort. The results of the CT decision change in the post-menopausal, post-RxPONDER patients by NPI and Predict demonstrate the utility of RS results across all NPI and Predict risk groups (Table 2). There was a stronger association between RS result (26-100 vs 0-25) and CT recommendation (OR152.8, 95% CI 53.9-433.2, p< 0.001) as compared to the association between either NPI or Predict (OR 8.7, 95% CI 3.8-19.8, p< 0.001 and OR 7.2, 95% CI 2.8-18.3, p=0.003 respectively), suggesting that UK Oncologists are predominantly using RS to guide their CT decisions. Conclusions: Either basing CT decisions or selecting which patients should undergo OncotypeDX testing by pre-screening with either NPI or Predict risks misclassifing many patients who either need potentially lifesaving CT or who can safely avoid chemotherapy altogether. Table 1. Predict and NPI risk groups by RS result for all patients and for the post-menopausal, post-RxPONDER cohort. Table 2. CT recommendation pre-and post-assay by risk group for post-menopausal, post-RxPONDER patients. Citation Format: Simon Holt, Paige Innis, Priyadharshini Sai-Giridhar, Satish Seerapu. A comparison of chemotherapy recommendations by NPI, Predict, and Oncotype DX testing in UK women with early node positive 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 PO1-14-05.

Abstract PO4-17-12: Early adherence to adjuvant abemaciclib: Data from the Belgian Medical Need Program

Abstract Patient adherence profiles for adjuvant hormonal therapy combined with abemaciclib in HR+/HER2- High Risk EBC based on real world evidence (RWE) from a Medical Need Program in Belgium Background Following results of MonarchE, demonstrating clinically meaningful improvement in invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS), a 2-year treatment with abemaciclib has been reimbursed in Belgium since May 1st, 2023 for the adjuvant treatment of HR+, HER2–, lymph node-positive (>3 or 1-3 if pT3 or grade 3) early breast cancer (EBC). In this trial, adverse event related treatment discontinuation was reported in 18,5% (8.9% after dose reduction) of which 10.1% in the first 5 months after starting this CDK 4/6 inhibitor. Prior to reimbursement, an early access program was initiated in Belgium on June 28 2022. We studied the proportion of patients estimated to be eligible for the program nationwide who effectively started adjuvant abemaciclib, as well as early treatment discontinuation and dose reductions. Methods The number of eligible patients for the adjuvant abemaciclib Medical Need Program (MNP) was estimated by the Belgian Cancer Registry based on the above mentioned reimbursement criteria for patients registered during the incidence year 2018. The MNP was active in Belgium from June 28 2022 until May 1 2023. Discontinuation rate and proportion with dose reductions were calculated using a nationwide prospective managed monthly updated register of participating patients including information on age at diagnosis, time since therapy start, delivered doses and patient reported adverse events (AE). They all signed an informed consent and agreed to share their registered data after anonymization. Data analysis was retrospective. Descriptive statistics were used. Results In this 10-month period, 840 patients were estimated to be eligible to receive adjuvant abemaciclib in Belgium. A total of 311 patients (309 women, 2 men) were included in the program, 37% of the estimated number of patients. Median age at initiation was 57 y. Median time on treatment was 4.5 months (156 patients >4.5 months on treatment). 21/311 (6.7%) patients discontinued (all causes). 2 patients never started. 10 patients (3.2%) discontinued their therapy without dose reduction. 12/311 (3.8%) had a starting dose of 2 × 100 mg/d. 128/311 (41.1%) had a dose reduction, 96/128 (75%) before 3 months of therapy. In the subgroup of 156 patients starting treatment >4.5 months ago, 16/156 (10.2%) discontinued treatment, 13 patients have not yet been reported. 79/156 (50.6%) required a dose reduction, of which 7 (4.5%) discontinued after dose reduction. The reasons for discontinuation reported: 8/21 (38%) gastro-intestinal intolerance, 3/21 (14.2%) real deterioration in renal function, 8/21 quality of life issues (not specified), 1/21 anal burning sensation and anal fistula, 3/21 asthenia and fatigue. Conclusion Of the estimated eligible patients in Belgium 37 % started with adjuvant abemaciclib. These results illustrate that there is a need to further improve implementation of adjuvant abemaciclib. Early results show that 89.8% of patients receiving adjuvant abemaciclib therapy in Belgium continued their treatment after 4.5 months and 50% of patients needed a dose reduction. Longer follow-up will be needed. Understanding the reasons of discontinuation and early dose adjustments can enable better patient support on adherence. This is a critical capability to ensure optimal patient compliance. Citation Format: Maxime Van Houdt, Marc Michaux, Sevilay Altintas, Ahmad Awada, Jean-Luc Canon, Hannelore Denys, François Duhoux, Guy Jerusalem, Jeroen Mebis, Rosanne Janssens, Isabelle Huys, Barbier Liese, Charlotte Verbeke, Sileny Han, Hans Wildiers, Patrick Neven. Early adherence to adjuvant abemaciclib: Data from the Belgian Medical Need Program [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 PO4-17-12.

Abstract PO1-03-02: Impact of Body Mass Index (BMI) on the efficacy of different adjuvant chemotherapy schedules in patients with breast cancer: analysis from the randomized phase III GIM2 trial

Abstract Background: The long-term results of the Italian randomized phase III GIM2 study showed that, in women with node-positive breast cancer (BC), dose-dense (DD) chemotherapy significantly improved both disease-free survival (DFS) and overall survival (OS) compared with standard-interval (SI) chemotherapy. Obesity has been identified as an independent poor prognostic factor in patients with BC, with a potential negative impact on the efficacy and toxicity of systemic therapies. Nevertheless, the specific influence of body mass index (BMI) on the efficacy of different adjuvant chemotherapy schedules (DD or SI) remains a subject of debate. This analysis aimed to investigate this hypothesis in patients enrolled in the GIM2 trial. Methods: GIM2 was a randomized multicentric phase III trial that compared different chemotherapy schedule (DD vs SI) and regimen (FEC-P vs EC-P) in 2091 node-positive early breast cancer patients. BMI (kg/m2) was categorized as follows: < 18.5 (underweight), 18.5 to < 25 (lean), 25 to < 30 (overweight), and ≥ 30 (obese). The primary endpoint was to assess association between BMI and DFS and OS. Survival estimates were compared using the Kaplan-Meier method and log-rank test. Univariate and multivariable Cox proportional hazard models, adjusted for relevant prognostic factors, were used. Results: A total of 1925 patients were included in the present analysis, of whom 31.6% (n=632) were overweight and 19.3% (n=386) obese. Median age was 52 years. Overweight-obesity condition was significantly associated with postmenopausal status, greater representation of T2-T4 tumors with N > 2 in both patients in the DD and SI arm. After a median follow-up of 15.0 years (IQR 8.4-16.3), compared to patients with normal BMI, those who were overweight or obese at diagnosis had a higher risk of experiencing a DFS event (Hazard Ratio [HR] 1.11 95% CI 0.94-1.31 and HR 1.37 95%CI 1.14-1.65, respectively, p=0.003) and OS event (HR 1.11 95% CI 0.89-1.38 and HR 1.59 95%CI 1.26-2.01, respectively, p=0.0003). No significant interaction was found between BMI and treatment schedule in terms of DFS (p for interaction=0.56) nor OS (p for interaction=0.19). At the multivariate analysis, in the DD arm, adjusted HR (aHR) for DFS and for OS were 1.01 (95% CI 0.75- 1.35) and 1.04 (95% CI 0.72-1.52) for obese vs. normal BMI groups, and 0.88 (95% CI 0.68- 1.15) and 0.77 (95%CI 0.54-1.10) for overweight vs. normal BMI groups, respectively. In the SI arm, aHRs for DFS and OS were 1.24 (95% CI 0.94- 1.63) and 1.35 (95%CI 0.96- 1.90) for obese vs. normal BMI groups, and 1.04 (95%CI 0.82- 1.33) and 1.01 (95% CI 0.74-1.40) for overweight vs. normal BMI groups, respectively. Similar results were observed when considering hormone receptor-positive and negative BC separately. Conclusion: In the GIM2 trial, BMI was prognostic but not predictive of different benefit to adjuvant chemotherapy. In high-risk patients, DD schedule should be considered the preferred schedule irrespective of BMI. Citation Format: Francesca Poggio, Eva Blondeaux, Marco Tagliamento, Marta Perachino, Simone Nardin, Benedetta Conte, Sabino De Placido, Mario Giuliano, Valeria Forestieri, Michelino De Laurentiis, Adriano Gravina, Giancarlo Bisagni, Anita Rimanti, Anna Turletti, Cecilia Nisticò, Angela Vaccaro, Francesco Cognetti, Alessandra Fabi, Simona Gasparro, Ornella Garrone, Ylenia Urracci, Maria Grazia Alicicco, Mauro Mansutti, Paola Poletti, Pierpaolo Correale, Claudia Bighin, Fabio Puglisi, Filippo Montemurro, Giuseppe Colantuoni, Luca Boni, Matteo Lambertini, Lucia Del Mastro. Impact of Body Mass Index (BMI) on the efficacy of different adjuvant chemotherapy schedules in patients with breast cancer: analysis from the randomized phase III GIM2 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 PO1-03-02.

Evaluating Radar Reflector Localisation in Targeted Axillary Dissection in Patients Undergoing Neoadjuvant Systemic Therapy for Node-Positive Early Breast Cancer: A Systematic Review and Pooled Analysis.

SAVI SCOUT® or radar reflector localisation (RRL) has proven accurate in localising non-palpable breast and axillary lesions, with minimal interference with MRI. Targeted axillary dissection (TAD), combining marked lymph node biopsy (MLNB) and sentinel lymph node biopsy (SLNB), is becoming a standard post-neoadjuvant systemic therapy (NST) for node-positive early breast cancer. Compared to SLNB alone, TAD reduces the false negative rate (FNR) to below 6%, enabling safer axillary surgery de-escalation. This systematic review evaluates RRL's performance during TAD, assessing localisation and retrieval rates, the concordance between MLNB and SLNB, and the pathological complete response (pCR) in clinically node-positive patients post-NST. Four studies (252 TAD procedures) met the inclusion criteria, with a 99.6% (95% confidence [CI]: 98.9-100) successful localisation rate, 100% retrieval rate, and 81% (95% CI: 76-86) concordance rate between SLNB and MLNB. The average duration from RRL deployment to surgery was 52 days (range:1-202). pCR was observed in 42% (95% CI: 36-48) of cases, with no significant migration or complications reported. Omitting MLNB or SLNB would have under-staged the axilla in 9.7% or 3.4% (p = 0.03) of cases, respectively, underscoring the importance of incorporating MLNB in axillary staging post-NST in initially node-positive patients in line with the updated National Comprehensive Cancer Network (NCCN) guidelines. These findings underscore the excellent efficacy of RRL in TAD for NST-treated patients with positive nodes, aiding in accurate axillary pCR identification and the safe omission of axillary dissection in strong responders.

Costs of breast cancer recurrence after initial treatment for HR+, HER2−, high-risk early breast cancer: estimates from SEER-Medicare linked data

Objective To assess the costs of treated recurrence and survival in elderly patients with early breast cancer (EBC) at high risk of recurrence using Surveillance Epidemiology and End Results (SEER) registry-Medicare linked claims data. Methods This retrospective study included patients aged ≥65 years with hormone receptor-positive (HR+), human epidermal growth factor receptor 2 negative (HER2−), node-positive EBC at high risk of recurrence. Treated recurrences were defined based on treatment events/procedure codes from claims. Primary outcomes were monthly total extra costs and cumulative extra costs of treated recurrence relative to patients with non/untreated recurrence. Costs were calculated using a Kaplan-Meier sampling average estimator method and inflated to 2021 US$. Secondary outcomes included analysis by recurrence type and overall survival (OS) after recurrence. Subgroup analysis evaluated costs in patients with Medicare Part D coverage. Results Among 3,081 eligible patients [mean (SD) age at diagnosis was 74.5 (7.1) years], the majority were females (97.4%) and white (87.8%). Treated recurrence was observed in 964 patients (31.3%). The monthly extra cost of treated recurrence was highest at the beginning of the first treated recurrence episode, with 6-year cumulative cost of $117,926. Six-year cumulative extra costs were higher for patients with distant recurrences ($168,656) than for patients with locoregional recurrences ($96,465). Median OS was 4.34 years for all treated recurrences, 1.92 years for distant recurrence, and 6.78 years for locoregional recurrence. Similar cumulative extra cost trends were observed in the subgroup with Part D coverage as in the overall population. Limitations This study utilizes claims data to identify treated recurrence. Due to age constraints of the dataset, results may not extrapolate to a younger population where EBC is commonly diagnosed. Conclusion EBC recurrence in this elderly population has substantial costs, particularly in patients with distant recurrences. Therapies that delay or prevent recurrence may reduce long-term costs significantly.

Prognostic impact of HER2-low positivity in patients with HR-positive, HER2-negative, node-positive early breast cancer

Adjuvant therapy for patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive, early breast cancer (EBC) remains challenging. The prognostic significance of HER2-low positivity in these patients is not fully understood. In our retrospective study, we analyzed 647 patients with HR-positive, HER2-negative, node-positive EBC, stratifying them into three cohorts based on axillary lymph node involvement, tumor size, and characteristics. Cohort 1 included patients with either ≥ 4 positive axillary lymph nodes or 1–3 positive nodes with histological grade 3 or tumor size ≥ 5 cm. Cohort 2 consisted of patients with 1–3 positive nodes, histological grade < 3, tumor size < 5 cm, and Ki-67 ≥ 20%. Cohort 3 comprised patients with 1–3 positive nodes, histological grade < 3, tumor size < 5 cm, and Ki-67 < 20%. We compared invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS) between HER2-low (IHC1+ or IHC2+/FISH−) and HER2-zero (IHC0) groups in each cohort. In cohort 1, HER2-low patients exhibited significantly better 5-year IDFS (84.2% vs. 73.6%, p = 0.0213) and DRFS (88.2% vs. 79.8%, p = 0.0154). However, no significant differences were observed in cohorts 2 and 3. Our findings suggest HER2-low positivity as a prognostic factor in HR-positive, HER2-negative, and node-positive EBC.

Cost-effectiveness analysis of abemaciclib with endocrine therapy (ET) versus ET alone for HR+, HER2-, node-positive, high-risk early breast cancer in Italy.

Abemaciclib was recently approved by the European Medicines Agency in combination with adjuvant endocrine therapy (ET) for adult patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-), node-positive early breast cancer (EBC) at high risk of recurrence. To evaluate the cost-effectiveness of abemaciclib plus ET vs. ET alone in patients with HR+, HER2-, node-positive EBC at high risk of disease recurrence, from the Italian healthcare system perspective. A cohort state transition model was developed with five states: invasive disease-free survival (IDFS), nonmetastatic recurrence, remission, metastatic recurrence, and death. The analysis had a time horizon of 30years. Individual patient-level data from the monarchE trial (NCT03155997) were used to generate IDFS estimates. Resource use included drug acquisition/administration, best supportive care, terminal care, adverse events, hospitalization, post-progression therapy, and associated resource use in the metastatic disease health state. Health state utilities were derived from monarchE patient-level data and other sources, applying Italian tariffs where feasible. The estimated total discounted costs (€39,249 vs. €16,806; difference: €22,443) and quality-adjusted life years (QALYs) (11.49 vs. 10.50; difference: 0.99) were higher for abemaciclib plus ET compared with ET alone. The incremental cost-effectiveness ratio was €22,651 per QALY gained. The likelihood of abemaciclib plus ET being cost-effective vs. ET alone was 99% at a willingness-to-pay threshold of €30,000 per QALY gained. Abemaciclib plus ET is a cost-effective treatment option vs. ET alone for those with HR+, HER2- node-positive EBC at high risk of recurrence in Italy.

Assessment of nuclear grade-based recurrence risk classification in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive high-risk early breast cancer

BackgroundHistological grade (HG) has been used in the MonrachE trial to select patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive high-risk early breast cancer (EBC). Although nuclear grade (NG) is widely used in Japan, it is still unclear whether replacing HG with NG can appropriately select high-risk patients.MethodsWe retrospectively reviewed 647 patients with HR-positive, HER2-negative, node-positive EBC and classified them into the following four groups: group 1: ≥ 4 positive axillary lymph nodes (pALNs) or 1–3 pALNs and either grade 3 of both grading systems or tumors ≥ 5 cm; group 2: 1–3 pALNs, grade < 3, tumor < 5 cm, and Ki-67 ≥ 20%; group 3: 1–3 pALNs, grade < 3, tumor < 5 cm, and Ki-67 < 20%; and group 4: group 2 or 3 by HG classification but group 1 by NG classification. We compared invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS) among the four groups using the Kaplan–Meier method with the log-rank test.ResultsGroup 1 had a significantly worse 5-year IDFS and DRFS than groups 2 and 3 (IDFS 80.8% vs. 89.5%, P = 0.0319, 80.8% vs. 95.5%, P = 0.002; DRFS 85.2% vs. 95.3%, P = 0.0025, 85.2% vs. 98.4%, P < 0.001, respectively). Group 4 also had a significantly worse 5-year IDFS (78.0%) and DRFS (83.6%) than groups 2 and 3.ConclusionsNG was useful for stratifying the risk of recurrence in patients with HR-positive, HER2-negative, node-positive EBC and was the appropriate risk assessment for patient groups not considered high-risk by HG classification.

The role of irradiation in the management of the axilla in early breast cancer patients.

The need for axillary radiotherapy in patients with invasive breast cancer (IBC) has been a topic of great debate in the last decade. Management of the axilla has evolved significantly over the past four decades with a trend towards de-escalation of surgical interventions and the aim of reducing morbidity and enhancing QOL without compromising long-term oncology outcomes. This review article will address the role of axillary irradiation with a focus on the omission of completion axillary lymph node dissection in selected patients with sentinel lymph node (SLN) positive early breast cancer (EBC) with reference to current guidelines based on evidence to date.

Prospective single-arm study of endocrine therapies with ovarian function suppression in premenopausal patients with node-positive early breast cancer with low genomic risk (INTERSTELLAR trial, KBCSG-25).

TPS618 Background: It is unclear whether the clinical benefit of cytotoxic adjuvant chemotherapy (CT) could be replaced by ovarian-function suppression (OFS) in premenopausal, estrogen receptor (ER)+HER2- breast cancer patients who have high clinical risk score and low genomic risk assessed by multigene assays. The TAILORx trial included a subgroup of premenopausal women with high clinical risk scores and midrange RS scores and found that CT, in addition to endocrine treatment (ET), offered clear benefits in terms of invasive disease-free survival (iDFS) and distant-recurrence-free survival (DRFS) compared to ET alone. However, a majority of the patients did not receive OFS, and the use of OFS as an alternative to chemotherapy in this population is still an area of ongoing research and debate. In addition, in premenopausal women of the RxPonder trial, which enrolled node-positive disease, it is noted that the addition of OFS to ET for at least 12 months improved iDFS numerically in the ET-alone arm, although this improvement did not reach statistical significance. We hypothesized that a favorable DRFS could be achieved by OFS plus ET without CT in premenopausal, pN1, ER+HER2- breast cancer with low genomic risk identified by an NGS-based multigene assay, the OncoFREE. Methods: The INTERSTELLAR trial is a prospective, multicenter, single-arm, non-inferiority clinical study. Premenopausal women aged ≤50 years with pT1-2 ER+HER2- breast cancer and 1-3 lymph node metastasis will be enrolled. They will be tested with OncoFREE, an NGS-based breast cancer prognosis multigene assay developed and available in South Korea, where a higher portion of the patients is premenopausal. Patients with low genomic risk (Decision Index≤20) are administered OFS plus tamoxifen or an aromatase inhibitor for five years. We hypothesize that the 5-year DRFS of the single arm treated with OFS plus ET would be not inferior to 96.1%, which is observed in the chemo-ET arm from the premenopausal subgroup of the RxPonder trial. The one-sided test with a non-inferiority margin of 3% and statistical power of 80% at a significance level of 0.05 resulted in a sample size of 380 patients with low genomic risk. Considering a 70% designation to low genomic risk by OncoFREE and a 10% drop-out rate, 604 patients will be enrolled from 15 tertiary care hospitals in South Korea. The primary endpoint will be tested in the 380 patients with low genomic risk. The patients with high genomic risk will receive CT followed by ET and will be followed for survival analysis as a secondary end-point. The trial has not enrolled its first patient yet at the time of submission. Clinical trial information: NCT05333328 .

Efficacy of Endocrine Therapy Plus Trastuzumab and Pertuzumab vs De-escalated Chemotherapy in Patients with Hormone Receptor–Positive/ERBB2-Positive Early Breast Cancer

Combination of chemotherapy with (dual) ERBB2 blockade is considered standard in hormone receptor (HR)-positive/ERBB2-positive early breast cancer (EBC). Despite some promising data on endocrine therapy (ET) combination with dual ERBB2 blockade in HR-positive/ERBB2-positive BC, to our knowledge, no prospective comparison of neoadjuvant chemotherapy vs ET plus ERBB2 blockade in particular with focus on molecular markers has yet been performed. To determine whether neoadjuvant de-escalated chemotherapy is superior to endocrine therapy, both in combination with pertuzumab and trastuzumab, in a highly heterogeneous HR-positive/ERBB2-positive EBC. This prospective, multicenter, neoadjuvant randomized clinical trial allocated 207 patients with centrally confirmed estrogen receptor-positive and/or progesterone receptor-positive (>1%) HR-positive/ERBB2-positive EBC to 12 weeks of standard ET (n = 100) vs paclitaxel (n = 107) plus trastuzumab and pertuzumab. A total of 186 patients were required to detect a statistically significant difference in pathological complete response (pCR) (assumptions: 19% absolute difference in pCR; power, ≥80%; 1-sided Fisher exact test, 2.5% significance level). Standard ET (aromatase inhibitor or tamoxifen) or paclitaxel, 80 mg/m2, weekly plus trastuzumab and pertuzumab every 21 days. The primary end point was pCR (ypT0/is, ypN0). Secondary end points included safety, translational research, and health-related quality of life. Omission of further chemotherapy was allowed in patients with pCR. PAM50 analysis was performed on baseline tumor biopsies. Of the 207 patients included (median [range] age, 53 [25-83] years), 121 (58%) had cT2 to cT4 tumors, and 58 (28%) had clinically node-positive EBC. The pCR rate in the ET plus trastuzumab and pertuzumab arm was 23.7% (95% CI, 15.7%-33.4%) vs 56.4% (95% CI, 46.2%-66.3%) in the paclitaxel plus trastuzumab and pertuzumab arm (odds ratio, 0.24; 95% CI, 0.12-0.46; P < .001). Both immunohistochemical ERBB2 score of 3 or higher and ERBB2-enriched subtype were independent predictors for pCR in both arms. Paclitaxel was superior to ET only in the first through third quartiles but not in the highest ERBB2 quartile by messenger RNA. In contrast with the paclitaxel plus trastuzumab and pertuzumab arm, no decrease in health-related quality of life after 12 weeks was observed in the ET plus trastuzumab and pertuzumab arm. The WSG-TP-II randomized clinical trial is, to our knowledge, the first prospective trial comparing 2 neoadjuvant de-escalation treatments in HR-positive/ERBB2-positive EBC and demonstrated an excellent pCR rate after 12 weeks of paclitaxel plus trastuzumab and pertuzumab that was clearly superior to the pCR rate after ET plus trastuzumab and pertuzumab. ClinicalTrials.gov Identifier: NCT03272477.

Impact of Adjuvant Abemaciclib on Service Provision within a District General Hospital Cancer Centre

Purpose: Two years of adjuvant abemaciclib with endocrine therapy was approved by NICE [1] in July 2022 for hormone receptor-positive (HR+) HER2-negative (HER2–) node-positive early breast cancer (EBC) at high-risk of recurrence. There is concern around additional oncology service provision needs of this cohort who would previously have been discharged to surveillance. We have therefore reviewed our service to estimate the impact of this additional treatment on projected service provision needs.

Prognostic and predictive impact of gene expression in node-positive early breast cancer patients receiving dose-dense versus standard-dose adjuvant chemotherapy.

The utility of multigene expression assays in advanced (≥ 4 positive lymph nodes) early breast cancer (EBC) is limited. We conducted exploratory transcriptomic analysis of 758 genes (Breast Cancer 360 panel, nCounter® platform; NanoString) in primary tumor samples collected during a phase 3 trial comparing adjuvant taxane-containing dose-dense chemotherapy (ddCTX) versus standard-dosed chemotherapy (stCTX) in resected EBC with ≥ 4 positive lymph nodes. Prognostic and predictive associations with disease-free survival (DFS) and overall survival (OS) were evaluated by Cox regression with false discovery rate (FDR) adjustment. Data were available from tumor samples of 141/226 patients (median follow-up: 14 years). Several genes/signatures, including immune markers, showed prognostic relevance in unadjusted analyses. Of these, two remained significant after multiplicity adjustment: a positive effect on DFS of programmed cell death 1 ligand-2 (PD-L2) in the ddCTX arm (univariate HR: 0.53, FDR-adjusted P = 0.036) and a negative effect on OS of HER2-enriched (HER2-E) signature in the stCTX arm (univariate HR: 5.40, FDR-adjusted P = 0.036). Predictive analyses showed greater DFS benefit of ddCTX in tumors with high antigen processing machinery (APM) expression (multivariate interaction P = 0.024). Multigene expression assays have a prognostic and predictive potential in advanced EBC, and further investigation is warranted in order to identify candidates for de-escalated treatment. In addition, intrinsic subtype and immune gene expression have predictive potential.

Abemaciclib in Combination with Endocrine Therapy for Adjuvant Treatment of Hormone Receptor-Positive, HER2-Negative, Node-Positive Early Breast Cancer: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited the manufacturer (Eli Lilly) of abemaciclib (Verzenios) to submit evidence for the clinical and cost effectiveness of this drug in combination with endocrine therapy (ET) for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive early breast cancer at high risk of recurrence, as part of the Institute's Single Technology Appraisal (STA) process. Kleijnen Systematic Reviews Ltd, in combination with Newcastle University, was commissioned to act as the independent Evidence Review Group (ERG). This paper summarised the Company Submission (CS), presents the ERG's critical review of the clinical and cost-effectiveness evidence in the CS, highlights the key methodological considerations, and describes the development of the NICE guidance by the Appraisal Committee. The ERG produced a critical review of the evidence for the clinical and cost-effectiveness evidence in the CS and also independently searched for relevant evidence and modified the manufacturer decision analytic model to examine the impact of altering some of the key assumptions. A systematic literature review identified the MonarchE trial, an ongoing, open-label, randomised, double blind trial involving 5637 people comparing abemaciclib in combination with ET versus ET alone. The trial included two cohorts that used different inclusion criteria to define high risk of recurrence. The ERG considered Cohort 1 as an adequate representation of this population and the AC concluded that Cohort 1 was generalisable to National Health Service clinical practice. Trial results showed improvements in invasive disease-free survival for the abemaciclib arm, which was considered an appropriate surrogate outcome. The ERG believed that the modelling structure presented in the de novo economic model by the company was appropriate but highlighted several areas of uncertainty that had the potential to have a significant impact on the resulting incremental cost-effectiveness ratio (ICER). Areas of uncertainty included the extrapolation of long-term survival curves, the duration of treatment effect and treatment waning, and the proportion of patients who receive other CDK4/6 treatments for metastatic disease after receiving abemaciclib. ICER estimates were £9164 per quality-adjusted life-year gained for the company's base-case and £17,810 for the ERG's base-case. NICE recommended abemaciclib with ET as an option for the adjuvant treatment of HR-positive, HER2-negative, node-positive early breast cancer at high risk of recurrence.

Abstract P4-02-06: Clinical and biological predictors of lymph node involvement in patients with early breast cancer for adjuvant treatment personalization

Abstract Background: Over the last years, the management of patients with node positive early breast cancer has gone through important innovations. On the medical side, new targeted therapies such as olaparib and abemaciclib have been introduced, with promising results on the invasive disease-free survival. Moreover, sparing axillary lymph node dissection has proven to be noninferior in terms of overall survival. However, no tools are currently available to predict lymph node involvement before definitive surgical evaluation. The aim of the study was to analyze clinical and pathological characteristics of patients with node positive early breast cancer to explore potential risk profiles associated with a ≥3 nodal involvement. Methods: The study retrospectively analyzed 335 node-positive breast cancer patients treated at the Breast Unit of the CRO Aviano National Cancer Institute, between 2017 and 2021. Data regarding primary tumor biological features, lymph node involvement and surgical approach were collected. Associations between clinico-pathological characteristics and ≥3 lymph node involvement were tested through stepwise logistic regression and the gradient boosting machine learning algorithm (GBM). Results: Among the 335 analyzed patients, 87.0% had a primary tumor &amp;lt; 5 cm, with a single positive lymph node in 73.3% of cases. Hormone receptors were mainly positive (respectively 93.5% and 83.4% for estrogen and progesterone receptors). Tumor grade was most frequently well differentiated (Grade 1 in 60.7%), with a Ki67 &amp;lt; 20% (59.5%). After multivariable logistic regression, a tumor size ≥ 3 cm (OR 3.24, CI95% 1.47-7.17, p = 0.004), the presence of massive lymphovascular stromal invasion (OR 2.50, CI95% 1.02-6.14, p = 0.045) and 2 or more positive sentinel lymph nodes at surgical evaluation (OR 6.08, CI95% 3.34-11.05, p &amp;lt; 0.001) were associated with a higher risk of identifying ≥ 3 positive lymph nodes after subsequent axillary dissection. Similar results were observed in the luminal-like cohort. A GBM machine learning model was then developed with a 0.77 Area Under the Curve. Features with the highest relative importance (RI) were single sentinel node involvement (RI 16.1873), followed by tumor size ≥ 3 cm (RI 10.2024), ≥2 positive sentinel lymph nodes (RI 8.5050) and lymphovascular stromal invasion (4.0217). Consistently, number of positive sentinel lymph nodes and tumor size were the predominant features in all top 20 GBM models. Conclusions: The present study explored the definition of risk profiles linked to 3 or more positive lymph nodes based on clinical and pathological features. It, moreover, tested the feasibility of developing machine learning classifiers to support future clinical decision-making. Due to the growing complexity of the adjuvant setting, finding a balance between minimally invasive surgical and staging approaches and risk definition for treatment personalization will become increasingly critical. Citation Format: Tania Pivetta, Brenno Pastò, Martina Urbani, Elisabetta Benozzi, Nicola De Pascalis, Tiziana Perin, Mario Mileto, Bruno Pasquotti, Erica Piccoli, Lorenzo Vinante, Chiara Bampo, Silvia Bolzonello, Mattia Garutti, Milena Nicoloso, Serena Corsetti, Simona Scalone, Lucia da Ros, Paola di Nardo, Camilla Lisanti, Simon Spazzapan, Barbara Belletti, Michele Bartoletti, Lorenzo Gerratana, Samuele Massarut, Fabio Puglisi. Clinical and biological predictors of lymph node involvement in patients with early breast cancer for adjuvant treatment personalization [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-06.

Abstract P2-02-03: Efficacy and Safety of the Addition of Internal Mammary Irradiation to Standard Adjuvant Radiation in Early-Stage Breast Cancer: A Systematic Review and Meta-analysis

Abstract Background: Adjuvant regional nodal irradiation together with whole breast or chest wall irradiation is considered standard of care in most node positive early breast cancer. Existing data on adding internal mammary irradiation (IMNI) to the regional nodal fields are inconsistent. The objective of this study was to conduct a meta-analysis to explore the efficacy and safety of adding IMNI to adjuvant radiotherapy in early-stage, high risk breast cancer. Methods: A search of PubMed and EMBASE identified randomized trials that investigated the addition of IMNI to standard adjuvant radiation in early-stage breast cancer. Hazard ratios (HRs) and 95% confidence intervals (CI) were extracted for overall survival (OS), breast cancer specific survival (BCSS), disease-free survival (DFS) and distant-metastasis free survival (DMFS). The odds ratios (ORs) for regional and loco-regional recurrence, non-breast cancer mortality, secondary non-breast cancer, contralateral breast cancer and cardiovascular morbidity and mortality were also extracted. These data where pooled in a meta-analysis using RevMan 5.4. Results: Analysis included 5 trials comprising 10,994 patients. Compared to the control group, IMNI was associated with a small, but statistically significant improvement in OS (HR=0.91, 95% 0.85-0.97, p=0.004), BCSS (HR=0.84, 95%0.77-0.92, p&amp;lt; 0.001), DFS (HR=0.89, 95% CI 0.82-0.98, p= 0.01) and DMFS (HR=0.89, 95% 0.81-0.98, p=0.02). IMNI was also associated with reduced odds for regional (OR=0.58, 95% 0.44-0.75, p&amp;lt; 0.001) and loco-regional recurrence (OR=0.85, 95% CI 0.72-1.00, p=0.04). Subgroup analyses for OS by tumor location (medial/central vs. lateral) and by nodal burden showed similar benefit is all subgroups. The odds for cardiotoxicity were higher, but did not reach statistical significance (OR=1.23, 95% 0.99-1.53, p=0.07). There was no association with cardiovascular mortality (OR=1.00, 95% 0.69-1.46, p=1.00). There were also comparable odds for non-breast cancer mortality (OR=1.05, 95% 0.79-1.41, p=0.74), secondary cancer (OR=0.95, 95% 0.82-1.10, p=0.51) and contra-lateral breast cancer (OR=1.07, 95% 0.77-1.51, p=0.68). Conclusions: Compared to the control group the addition of IMNI in high-risk patients is associated with a statistically significant improvement in survival, albeit with a magnitude of questionable clinical meaningfulness. Non-significant association with increased cardiovascular toxicity requires further study in longer-term studies. Citation Format: Yasmin Korzets, Dina Levitas, Ahuva Grubstein, Ben W Corn, Eitan Amir, Hadar Goldvaser. Efficacy and Safety of the Addition of Internal Mammary Irradiation to Standard Adjuvant Radiation in Early-Stage Breast Cancer: A Systematic Review and Meta-analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-02-03.

Abstract P6-01-11: A UK prospective multicentre decision impact, decision conflict and economic evaluation of the use of Oncotype DX® to guide chemotherapy in 680 women with hormone receptor positive, HER2 negative breast cancer and 1 to 3 nodes involved

Abstract Introduction: For a test to be of value, it needs to demonstrate that it is changing clinical decisions, improving clinical confidence and of economic benefit. This trial looked at the use of Oncotype DX Breast Recurrence Score ® (RS) assay against these criteria in 680 women with hormone receptor positive (HR+), HER2 negative early breast cancer with 1 to 3 lymph nodes positive (LN+) in the UK National Health Service (NHS) (5 teaching and 9 district general hospitals) between 2017 and 2022. Methods: Patients with LN+ early breast cancer who were willing and fit to receive chemotherapy (CT) were consented to join the trial. At the initial oncologists’ appointment, physicians were asked to state their preference for or against CT and their level of confidence in their decision on a scale of 1 to 5. Following receipt of the RS result physicians were asked to make a final decision for or against CT and similarly record their level of confidence. Descriptive analyses were used to characterize (1) patient and tumour characteristics, (2) change in treatment recommendations post-RS testing (by RS result and nodal status), and (3) change in physicians’ level of confidence post-RS testing (by RS result and nodal status). Average cost for chemotherapy and RS test price were used to estimate overall cost savings. Results: A total of 680 patients were recruited. 16 patients were excluded (5 failed samples, 5 withdrew consent, 3 HER2 positives, 2 with advanced disease, and 1 specimen delayed in transit), leaving 664 assessable patients. The median age was 58 years and 77.1% of women were post-menopausal. Most patients had a RS of 0-17 (n=400, 60.2%); while 206 (31%) had a RS of 18-30 and 58 (8.7%) had a RS of 31-100. Using post-RxPONDER cutoffs, 566 (85.2%) had an RS of 0-25; 98 (14.8%) had an RS of 26-100. Decision impact results: The decision impact results broken down by RS result and nodal status are detailed in Table 1. Of the 662 patients with complete decision impact data, in 359 (54.2%) the recommendation by the physician changed from CT+ hormone therapy (HT) to HT alone. In 286 (43.2%) cases the decision was unchanged and in 17 (2.6%) the recommendation changed from HT alone to CT+HT. Overall 342 (51.7%) cases were spared chemotherapy. Decision conflict results: The change in the physicians’ level of confidence by RS result and nodal status are detailed in Table 2. Of the 660 cases with complete decision conflict data, physicians reported an increase in confidence in their recommendations after receiving the RS in 363 (55.0%), confidence was unchanged in 219 (33.2%) and decreased confidence in 78 (11.8%) cases. Economic analysis: Using the estimates of Burdanov et al, the average costs of a course of chemotherapy in the UK is £6,000 to £7,000. An estimate of the overall cost saving of 342 courses is £2,064,00 to £2,408,000 and the overall cost of 664 RS assays at the list price of about £2580 (although an undisclosed discount applies to the NHS) is £1,713,120. This suggests that the use of RS assay represents a significant saving to the NHS. Conclusion: The use of Oncotype DX assay in node positive early breast cancer leads to about half of women being spared chemotherapy, a significant improvement in clinical confidence for oncologists and an economic saving to the health care system. Table 1 Pre- vs Post-Oncotype DX Treatment Recommendation by Physician According to Recurrence Score and Nodal Status Table 2 Change in Physicians’ Level of Confidence Post-Oncotype DX Testing According to Recurrence Score and Nodal Status Citation Format: Simon D. Holt, Priyadharshini Sai-Giridhar, Mark Verrill, Laura Pettit, Anna Rigg, Tamas Hickish, Caroline D. Archer, Anshu Wadhawan, Marianne Dillon, Jo Dent, Mark R. Nathan, Ludger Barthelmes, Shazza rehman, Paige Innis, Saira Khawaja. A UK prospective multicentre decision impact, decision conflict and economic evaluation of the use of Oncotype DX® to guide chemotherapy in 680 women with hormone receptor positive, HER2 negative breast cancer and 1 to 3 nodes involved [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-11.