INTRODUCTION:Develop a multimodal model based on ultrasound (US) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data for predicting lymphovascular invasion (LVI) in breast cancer. METHOD:A total of 326 patients with breast cancer were enrolled in this retrospective study. All participants underwent preoperative US and DCE-MRI. Data from Center 1 (n = 167) were divided into a training set and an internal validation set, while data from Center 2 (n = 159) were used as the external validation set for analysis. A fusion feature set was constructed from intratumoral regions of US and DCE-MRI using deep transfer learning (DTL) features. Among three machine learning models - support vector machine, k-nearest neighbors, and multi-layer perceptron (MLP) - the MLP classifier trained with a feature subset selected via LASSO achieved optimal performance across multiple feature selection methods and was thus designated as the final model. The diagnostic performance and clinical utility of the multimodal model were validated and assessed through the area under the receiver operating characteristic curve and decision curve analysis. Model interpretability was assessed using Shapley Additive Explanations (SHAP). RESULT:Results indicate that the multimodal model, utilizing DTL features from US and DCE-MRI within the tumor region, demonstrates outstanding performance in classifying LVI in breast cancer. The area under the curve (AUC) values of the model were 0.987 in the training set, 0.967 in the internal validation set, and 0.942 in the external validation set. Its performance was significantly better than the models using DTL features derived from single-region US (AUC: 0.966, 0.852, 0.789) or DCE-MRI (AUC: 0.936, 0.716, 0.746), indicating great value for clinical application. CONCLUSION:Multimodal models based on DTL features can accurately distinguish LVI status in breast cancer patients. This model demonstrates promising application prospects in distinguishing LVI in breast cancer, with its value lying in effectively enhancing diagnostic accuracy and robustness.

Abstract Introduction MarvelD2 (Tricellulin), a MARVEL domain protein seen at tricellular regions, is essential for paracellular barrier integrity. Its dysregulation may disturb polarity and permeability and promote epithelial–mesenchymal transition (EMT), suggesting a role in cancer development and progression. Methods In a cohort of breast cancer tissues, we assessed MarvelD2 expression using quantitative transcript analysis and examined its association with prognosis in relation to tumour staging, molecular subtypes and hormonal receptor status. Results MarvelD2 expression was found to be highly aberrant in breast tumours when compared with normal mammary tissues (P = 0.0126). High MarvelD2 was associated with poorer overall survival (P = 0.014), particularly in ER-positive (P = 0.007 versus ER negative), HER2-negative (P = 0.023 versus HER2 positive), EGFR-negative (P = 0.020 versus EGFR positive) and HER4-negative (P = 0.015 versus HER4 positive) subgroups. Disease-free survival (DFS) also tended to be reduced in patients with high MarvelD2 (P = 0.067), with this trend being significant in EGFR-negative (P = 0.009), HER4-negative (P = 0.049) patients and in patients with low levels of PGR (P = 0.006). Across molecular subtypes, high MarvelD2 predicted poorer prognosis in non-triple-negative breast cancers (P = 0.017), especially in ER-positive/HER2−negative tumours (P = 0.024). Multivariate Cox regression identified MarvelD2 expression and aromatase levels as independent prognostic factors. High MarvelD2 conferred a significantly increased risk of death (HR = 13.07, 95% c.i.: 2.10–81.47, P = 0.006), while elevated aromatase was similarly linked to adverse outcomes (HR = 38.32, 95% c.i.: 2.34–627.65, P = 0.011). Conclusions MarvelD2 has significant clinical relevance in breast cancer. Its expression correlates with both overall and disease-free survival, supporting its potential as a prognostic biomarker and therapeutic target.

Background:Long-term survival in early-stage breast cancer patients has markedly improved, making follow-up an increasingly prolonged phase of care. Accurate prognosis assessment and a scientifically grounded follow-up plan are essential for achieving effective and individualized chronic disease management. This guideline aims to standardize these practices in China. Methods:The Chinese Society of Breast Surgery (CSBrS) convened a panel of experts. Clinical evidence was assessed according to a modified GRADE system. Recommendations were developed by integrating evidence quality with practical feasibility in the Chinese healthcare setting. A consensus voting committee of 33 breast surgeons graded the recommendation strength (Level A: ≥90% agreement; Level B: 80-89% agreement). Results:This guideline centers on two core components: prognosis and follow-up. A comprehensive prognosis integrates four domains: patients' general health, including age, genetic risk, reproductive history, and past medical history; tumor staging and histopathological characteristics; molecular features like subtype, Ki-67, BRCA mutations, and multigene assay results; and treatment factors, notably surgical margin status and adjuvant regimens. Follow-up recommendations visit frequency started with every 3-6 months, then 6-12 months, transitioning to annual lifelong checks, with adjustments based on risk. Evaluations should cover general examination, tumor-related examinations, special examinations, assessment of psychosocial well-being and treatment-related complications. Implementing a structured single-disease database is also advised to support continued care and research. Conclusions:This guideline provides evidence-based, consensus-driven recommendations for the prognostic evaluation and follow-up of early-stage breast cancer patients in China. Adopting this guideline within a multidisciplinary, patient-centered framework is vital for enhancing long-term survival and quality of life.

The real-world application of tracers for axillary sentinel lymph node biopsy (SLNB) for breast cancer (BC) after neoadjuvant chemotherapy (NAC) in China was unknown. We analyzed the use of individual tracers or combinations and number of SLNs in patients with BC who underwent SLNB with or without axillary lymph node dissection (ALND) after NAC in 20 hospitals in ten years. A total of 1251 BC patients underwent SLNB or SLNB + ALND after NAC, including 853 (68.2%, 853/1251) with a single tracer, predominantly Methylene blue (MB) (60.1%, 752/1251); and 398 (31.8%, 398/1251) with dual tracers, mainly MB combined with radioisotope (RI) (18.1%, 226/1251).The results showed that the predominance of the MB single-tracer method for SLNB after NAC limits the popularity of SLNB in patients with BC after NAC in China. MB combined with RI is the main dual-tracer method, and detects SLNs more effectively than MB alone.

PurposeThis study aimed to investigate the factors associated with pathologic node-negativity (ypN0) in patients who received neoadjuvant chemotherapy (NAC) to develop and validate an accurate prediction nomogram.MethodsThe CSBrS-012 study (2010–2020) included female patients with primary breast cancer treated with NAC followed by breast and axillary surgery in 20 hospitals across China. In the present study, 7,711 eligible patients were included, comprising 6,428 patients in the primary cohort from 15 hospitals and 1,283 patients in the external validation cohort from five hospitals. The hospitals were randomly assigned. The primary cohort was randomized at a 3:1 ratio and divided into a training set and an internal validation set. Univariate and multivariate logistic regression analyses were performed on the training set, after which a nomogram was constructed and validated both internally and externally.ResultsIn total, 3,560 patients (46.2%) achieved ypN0, and 1,558 patients (20.3%) achieved pathologic complete response in the breast (bpCR). A nomogram was constructed based on the clinical nodal stage before NAC (cN), ER, PR, HER2, Ki67, NAC treatment cycle, and bpCR, which were independently associated with ypN0. The area under the receiver operating characteristic curve (AUC) for the training set was 0.80. The internal and external validation demonstrated good discrimination, with AUCs of 0.79 and 0.76, respectively.ConclusionWe present a real-world study based on nationwide large-sample data that can be used to effectively screen for ypN0 to provide better advice for the management of residual axillary disease in breast cancer patients undergoing NAC.

Abstract Background. Diagnosis and treatment of breast cancer have been profoundly improved in China recently. However, trends in disparities and transitions of target treatment in early stage with ERBB2 positive between China and United States are not well known. Methods. This cross-sectional study used Chinese Society of clinical oncology breast cancer (CSCO BC) database from hospitals in 13 provinces of China and Flatiron database from more than 280 US community oncology clinics. Patients with ERBB2 positive and diagnosed as stage I to III breast cancer from 2011 to 2021 were collected. The distribution of target therapy was examined overall and by years. Results. A total of 10245 early-stage breast cancer with ERBB2 positive diagnosed from 2011 to 2021 were screened from the CSCO BC database(n=8446) and the Flatiron Database(n=1799). The median age at diagnosis for Chinese and US was 47 years old and 63 years old. For neoadjuvant therapy, the annual rate of trastuzumab-therapy increased from 0.4% in 2011 to 33% in 2021 in CSCO BC database, while rate of trastuzumab and pertuzumab therapy increased from 0.6% in 2016 to 42% in 2021. The proportion of trastuzumab therapy in Flatiron database decreased from 50% in 2011 to 23% in 2021, while the proportion of dual target therapy increased from 11% in 2013 to 67% in 2021. In adjuvant setting, the trastuzumab therapy increased from 6.8% in 2011 to 37% in 2021 in CSCO BC database, with highest proportion of 65% in 2018. Only 0.1% of patients received dual target therapy in 2018, the proportion increased to 32% in 2021. In Flatiron database, the trastuzumab therapy decreased from 60% in 2011 to 50% in 2021, while rate of trastuzumab and pertuzumab therapy increased from 5% in 2015 to 10% in 2021. Further follow-up is needed for survival data from two databases. Conclusions. Although significant differences were found between the China and US in target therapy, the disparities have been gradually narrowed. Use of trastuzumab in China has overtaken that in US since 2017 attributed to the effort of China's health reform in medical insurance and the promotion of guidelines. Citation Format: Jianbin Li, Jifang Zhou, Haibo Wang, Zhenzhen liu, Zhimin Fan, Yinhua Liu, Cuizhi Geng, Zefei Jiang. Trends in Disparities and Transitions of target therapy in Patients With ERBB2 Positive Early Breast Cancer in China and the US, 2011 to 2021 [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 PO2-04-02.

Objective Our aim was to compare the PIK3CA mutation status in matched primary and recurrent tumors of hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer (BC) to gain insight into the optimization of patient selection and detection time for PIK3CA-targeted therapy.Methods The data were from 3035 patients with BC diagnosed at the Breast Disease Center, Peking University First Hospital, between January 2008 and December 2017. Matched primary and recurrent samples were profiled using amplification-refractory mutation system-polymerase chain reaction covering 11 mutational hotspots in PIK3CA.Results PIK3CA mutations were detected in 54.3% primary tumors and 48.6% corresponding recurrences. PIK3CA mutation was detected in 37.5% cases in the locoregional recurrent group and 40.0% of distant metastasis, without a statistical difference. Besides, PIK3CA mutations were concordant in 88.6% of the matched pairs. For patients treated with neoadjuvant chemotherapy, 100% concordance was observed. However, PIK3CA mutation was neither correlated with clinicopathological features nor associated with clinical outcomes.Conclusions Mutations in PIK3CA in HR+/HER2- BC generally progressed to recurrent tumors. The high concordance rate of PIK3CA mutation status between primary tumors and corresponding recurrences suggests that the detection of primary tumors could be a substitute approach when recurrent samples are not easily obtainable. The highly consistency of PIK3CA mutation status between primary and recurrent tumors suggests that detecting mutations in primary tumors could substitute for analysis of recurrent samples when they are not easily obtainable.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor prognosis and limited treatment options. Although immune checkpoint inhibitors (ICIs) have been proven to improve outcomes in TNBC patients, the potential mechanisms and markers that determine the therapeutic response to ICIs remains uncertain. Revealing the relationship and interaction between cancer cells and tumor microenvironment (TME) could be helpful in predicting treatment efficacy and developing novel therapeutic agents. By analyzing single-cell RNA sequencing dataset, we comprehensively profiled cell types and subpopulations as well as identified their signatures in the TME of TNBC. We also proposed a method for quantitatively assessment of the TME immune profile and provided a framework for identifying cancer cell-intrinsic features associated with TME through integrated analysis. Using integrative analyses, RARRES1 was identified as a TME-associated gene, whose expression was positively correlated with prognosis and response to ICIs in TNBC. In conclusion, this study characterized the heterogeneity of cellular components in TME of TNBC patients, and brought new insights into the relationship between cancer cells and TME. In addition, RARRES1 was identified as a potential predictor of prognosis and response to ICIs in TNBC.

Neoadjuvant therapy can yield clinical benefits in early-stage breast cancer with indications. The indications, treatment regimens, and efficacy of neoadjuvant therapy have been investigated, which have contributed valuable clinical evidence.[1,2] The Chinese Society of Breast Surgery convened a panel of breast disease experts to review and discuss the literature on neoadjuvant therapy for breast cancer and evaluate relevant evidence by referring to the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system. Taking into account China's specific circumstances, the society and participating experts developed the Clinical Practice Guidelines for Neoadjuvant Therapy for Early-stage Breast Cancer (Version 2022) to serve as a reference for breast surgeons in China. Level of Evidence and Recommendation Strength The grading system for the level of evidence was developed by referring to the GRADE system and the findings from clinical studies in China, as indicated in the guideline evaluation system [Supplementary Table 1, https://links.lww.com/CM9/B963]. The recommendation strength of these guidelines combines the GRADE system and the specific characteristics of clinical practice in China [Supplementary Tables 2 and 3, https://links.lww.com/CM9/B963]. Recommendations Qualifications of the neoadjuvant therapy team The expert panel recommends that a multidisciplinary team (MDT) fully participate in the development and adjustment of neoadjuvant therapy strategies.[3] An MDT team should include members from the imaging, pathology, breast surgery, oncology, gynecology, genetic counseling, psychology, and nursing departments. Indications for neoadjuvant therapy The expert panel concurs with the indications for neoadjuvant therapy for early-stage breast cancer patients recommended by the Chinese Society of Clinical Oncology (CSCO) guidelines for breast cancer diagnosis and treatment. They highly recommend the implementation of neoadjuvant therapy for patients with indications. The indications for neoadjuvant therapy (grade IA) include a large tumor size (>5 cm), axillary lymph node metastasis, human epidermal growth factor receptor-2 (HER2)-positive breast cancer, triple-negative breast cancer, and breast-conservation intentions, but a large tumor size and breast volume pose a challenge for conserving the breasts.[1] Neoadjuvant treatment regimen The expert panel recommends that the standard adjuvant therapy regimen for breast cancer should serve as a reference when formulating neoadjuvant therapy strategies (grade IA). During neoadjuvant therapy, the appropriate dosage and duration of treatment should be administered (grade IA). The use of immune checkpoint inhibitors platinum drugs, or poly ADP ribose polymerase (PARP) inhibitors should be individualized (grade IA).[4] Neoadjuvant therapy evaluation The expert panel recommends conducting thorough evaluations before administering neoadjuvant therapy in breast cancer patients. The functions of vital organs should be evaluated by imaging and hematological examinations (grade IA) before neoadjuvant therapy. Oncology evaluations should be performed before neoadjuvant therapy. A staged evaluation should be conducted following the American Joint Committee on Cancer (AJCC) (version 8), and distant metastasis should be excluded by computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET)-CT, or radionuclide scans (grade IA).[5] The expert panel recommends conducting a description of the breast tumor and/or axillary lymph node diameter before treatment using ultrasound, X-ray, and dynamic enhanced MRI (grade IA). Localization and marking of lesions should be conducted using tattoo/tumor description/metal clip implantation before treatment (grade IA). Localization and marking of positive axillary lymph nodes should be conducted with metal clip implantation before treatment (grade IA). The expert panel recommends evaluating the efficacy of neoadjuvant therapy every two cycles, using the same imaging method as the one used at baseline, following the Response Evaluation Criteria in Solid Tumors (RECIST) (1.1) (grade IA). The expert panel strongly recommends performing core needle biopsy (CNB)/vacuum-assisted breast biopsy (VABB) to obtain a histopathological diagnosis of breast lesions/lymph nodes before neoadjuvant therapy (grade IA). Secondary CNB and pathological evaluation of lesions can be performed for efficacy evaluation (grade IIA). Pathological efficacy evaluations should be conducted using the Miller & Payne/residual tumor burden (RCB) grading system (grade IA). Surgery after neoadjuvant therapy The expert panel recommends conducting planned neoadjuvant therapy for ≥4 cycles (grade IA). The timing of surgery following neoadjuvant therapy should be individualized, taking into account efficacy, patient compliance, tumor staging, and molecular typing.[6] Surgery should be recommended following imaging evaluations of clinical complete response (cCR) to neoadjuvant therapy (grade IA). Furthermore, surgery must adhere to the principle of achieving R0 resection (grade IA). Systemic treatment after neoadjuvant therapy The expert panel recommends that optional systematic treatment following neoadjuvant therapy should be determined by tumor staging, treatment response, and molecular typing (grade IA).[7] Conflicts of interest None. Statement These guidelines serve as a reference for breast disease specialists in clinical practice. However, these guidelines should not be used as the foundation for medical evaluation, nor do they arbitrate in any medical disputes. The guidelines are not intended for patients or non-breast specialists. The Chinese Society of Breast Surgery bears no responsibility for any results resulting from the improper application of these guidelines but reserves the right to interpret and revise the guidelines.

AIM:This study aims to identify suitable candidates for axillary sentinel lymph node biopsy (SLNB) or targeted axillary dissection (TAD) among clinical N2 (cN2) triple-negative (TN) or HER2 positive (HER2+）breast cancer patients following neoadjuvant therapy（NAT）. BACKGROUND:Despite the substantial axillary burden in cN2 breast cancer patients, high pathological response rates can be achieved with NAT in TN or HER2+ subtypes, thus enabling potential downstaging of axillary surgery. METHODS:A retrospective analysis was conducted on data from the CSBrS-012 study, screening 709 patients with initial cN2, either HER2+ or TN subtype, from January 1, 2010 to December 31, 2020. The correlation between axillary pathologic complete response (pCR) (yPN0) and breast pCR was examined. RESULTS:Among the 177 cN2 patients who achieved breast pCR through NAT, 138 (78.0 %) also achieved axillary pCR. However, in the 532 initial clinical N2 patients who did not achieve breast pCR, residual axillary lymph node metastasis persisted in 77.4 % (412/532) of cases. The relative risk of residual axillary lymph node metastasis in patients who did not achieve breast pCR was 12.4 (8.1-19.1), compared to those who did achieve breast pCR, P < 0.001. CONCLUSION:For cN2 TN or HER2+ breast cancer patients who achieve breast pCR following NAT, consideration could be given to downstaging and performing an axillary SLNB or TAD.

To the Editor: In the last decade, neoadjuvant chemotherapy (NAC) has become a well-accepted treatment option for breast cancer, although few detailed description of NAC in China has yet been reported.[1] A previous study found that among patients with clinically node-negative (cN0) breast cancer, 97.7% (432/442) with breast pathologic complete response (bpCR) had ypN0 (absence of metastases in the axillary lymph nodes); and 71.6% (882/1232) without bpCR achieved ypN0 (P <0.001). As for human epidermal growth factor receptor 2 (HER2) positive or triple-negative breast cancer (TNBC) that achieved bpCR, the probability of lymph node metastasis was less than 2%. This research aimed to investigate NAC status in China using data obtained from the Chinese Society of Breast Surgery (CSBrS) study from 2010 to 2020. It seeks to answer the following questions: what the current trend in NAC utilization is and what the effects of breast and axillary lymph node are in China. Data were obtained from 20 hospitals in China by CSBrS study (analyzed the data from January 1, 2010 to December 31, 2020). This study was approved by the Ethics Committee of the First Hospital of Jilin University (No. 2021-066). This clinical study was a retrospective study, the application for exemption of informed consent was submitted, and the exemption was approved. Data collection and exclusion criteria are provided in Supplementary Figure 1, https://links.lww.com/CM9/B719. bpCR was defined as the absence of both invasive and cancer in situ within the breast, and ypN0 defined as the absence of metastasis within the axillary lymph nodes after NAC. Isolated tumor cell (ITC) was defined as ypN positive. Patients were defined as cN0 prior to NAC if imaging examination and/or lymph node(s) biopsy showed no evidence of metastasis. Patients were defined as cN1 if the axillary lymph node biopsy confirmed nodal involvement and/or the lymph node(s) were movable at palpation. General information regarding clinical and pathologic patient data was evaluated. Data were presented as numbers and percentages. Proportions were compared between groups by χ2 analysis. SPSS (version 22.0; IBM Corp., Chicago, IL, USA) and Prism 9 (GraphPad Software, San Diego, CA, USA) were used for statistical analysis. All statistical tests were based on a two-sided probability, and P <0.001was considered statistically significant. A total of 11,108 patients scheduled NAC, and 10,713 patients were deemed to be eligible and were included in the final analysis. Demographics and clinical characteristics of enrolled patients are provided in Supplementary Table 1, https://links.lww.com/CM9/B719; and initial chemotherapy regimen information is provided in Supplementary Table 2, https://links.lww.com/CM9/B719. The overall usage rate for NAC increased from 9.3% in 2010 to 16.2% in 2020 [Supplementary Figure 2, https://links.lww.com/CM9/B719]. The NAC rate differed across hospitals, with the lowest rate being 3.8% and the highest being 36.4% in 2020. For HER2+ breast cancer patients, the use of targeted therapy increased annually, with the usage rate reaching 65.1% in 2020 [Supplementary Figure 3A, https://links.lww.com/CM9/B719]. The percentage of patients who underwent breast-conserving surgery, axillary lymph node biopsy, and sentinel lymph node biopsy (SLNB) increased annually [Supplementary Figure 3B–D, https://links.lww.com/CM9/B719]. Based on the subtype analysis, the rates of bpCR were 5.8% (52/904), 13.3% (449/3386), 22.1% (486/2201), 31.9% (509/1596), and 30.4% (499/1644) for luminal A, luminal B, hormone receptor (HR)+/HER2–, HR–/HER2+, and TNBC, respectively [Supplementary Table 3, https://links.lww.com/CM9/B719]. In this study, 15.3% (1567/10,254) had total pathologic complete response (pCR) in both breast and lymph nodes, and 30.1% (3086/10,254) had axillary pathologic complete response (apCR) with residual tumor in breast; and 5.0% (511/10,254) had bpCR with positive lymph node metastasis. A total of 6142 patients with cT1-2N0-1 breast cancer were included for the association of bpCR with the absence of axillary lymph node metastasis. A higher proportion of ypN0 was found among cT1-2N0 patients with bpCR than among their counterparts (100.0% [8/8] vs. 60.5% [107/177] for luminal A, P = 0.025 85.3% [93/109] vs. 58.4% [353/604] for luminal B, P <0.001; 90.6% [126/139] vs. 72.8% [249/342] for HR+/HER2+, P <0.001; 94.5% [103/109] vs. 78.5% [153/195] for HR–/HER2+, P <0.001; and 93.7% [133/142] vs. 80.2% [223/278] for TNBC, P <0.001) [Supplementary Table 4, https://links.lww.com/CM9/B719]. Overall, for patients with cT1-2N0 cancer, the proportion with ypN0 was 91.3% (463/507) with bpCR, while the proportion was 68.0% (1085/1596) for patients without bpCR (P <0.001). Among the patients with cT1-2N1 who achieved bpCR, 47.4% (9/19) of luminal A patients were free from lymph node involvement; 62.4% (138/221) for luminal B; 72.3% (146/202) for HR+/HER2+; 80.0% (180/225) for HR–/HER2+; and 74.6% (205/872) for TNBC [Supplementary Table 4, https://links.lww.com/CM9/B719]. Overall, for these patients, 71.8% (626/872) with bpCR achieved ypN0; and 31.9% (1010/3167) without bpCR achieved ypN0 (P <0.001). As shown in Supplementary Table 5, https://links.lww.com/CM9/B719, among the 872 bpCR patients (cT1-2N1), 246 had lymph node metastasis after NAC, 64.6% (159/246) had ypN1, and 35.4% (87/246) had ypN2–3 metastasis. For HR–/HER2+ and TNBC cancer, only 4.4% and 10.2% patients had more than three metastatic lymph nodes. In this multicenter retrospective cohort study, we found that the overall usage rate of NAC for breast cancer in China has increased within the last decade, although the rate varies greatly due to region, hospital, or the attitudes of patients and doctors. In this study, the proportion of targeted drugs used is 40.5%.Although the rate is not as high as that used in clinical trials, it is still higher than that in the study of Li et al[2] (32.5%) from China, CSBrS-006. Axillary status after NAC has been consistently reported as a robust prognostic factor for patient survival independent of primary tumor response. We sought to answer whether a pathologic primary tumor response to NAC could predict axillary lymph node status.[1,3] Among the patients with cT1-2N0 breast cancer who achieved bpCR post-NAC, over 90.0% of the patients had no residual nodes, particularly among those with HR–/HER2+ or TNBC patients. Among those with cN1 breast cancer, more patients had residual cancer in the lymph nodes regardless of whether bpCR was achieved. According to the consensus of the 2017 St. Gallen International Expert Meeting, for patients with stage cN0 disease who receive NAC, SLNB is safe and recommended after NAC.[4] The GANEA2 study[5] also confirmed the accuracy and safety of SNLB after NAC for breast cancer patients. For cN0 patients, apCR was strongly related to the breast cancer subtypes. apCR rates were 93.3%, 98.4%, 100%, and 98.5% for HR+/HER2–, HR+/HER2+, HR–/HER2+, and TNBC patients, respectively. Barron et al[3]. found that the rates of ypN0 for patients with cN0 HER2+ or TNBC breast cancer, who achieved bpCR after NAC, were 99.0% and 98.4%, respectively. In this study, patients with cN0 HR–/HER2+ cancer or TNBC who achieved bpCR after NAC had ypN0 rates of 94.5% and 93.7%, respectively. For TNBC and HR–/HER2+ patients with cN0, our results indicate that it may be safe to implement SLNB instead of ALND after NAC. Since the ypN0 rates of these patients are high, it may also be feasible for cN0, bpCR, and HR-/Her2+,TNBC patients to omit SLNB. CSBrS initiated this multicenter retrospective study to further confirm whether this is a universal phenomenon that does exist in the real world. However, more clinical data are required for follow-up safety verification. Caution is necessary for patients with cT1-2N1, treated with SLNB and with axillary lymph node degeneration after NAC. It is necessary to use dual tracers for the detection of ≥3 sentinel lymph nodes (SLNs), and the placement of marker clips for the identification of positive lymph nodes before NAC, as well as markers removal during surgery.[7] The ACOSOG Z1071 trial found that after double marker identification, ≥3 SLNs reduced the false negative rate to 9.8%. In the GANEA2 study[5], for patients with initially involved lymph nodes who had negative SLNs after NAC, in the absence of lymph vascular invasion, and given a remaining breast tumor size of less than 5 mm, the risk for a positive ALND was 3.7%, regardless of the number of SLNs that were removed. Barrio et al[8] found that among 610 patients, 555 (91%) cN1 improved to cN0 after NAC and underwent SLNB. The results demonstrated cN1 patients with three or more negative SLNs and nodal radiation, although without routine nodal clipping, nodal recurrence rates were low. These findings support the possibility of omission of ALND for such patients. In this study, for all subtypes of breast cancer, the number of axillary lymph node metastases gradually decreased as the number of positive nodes increased [Supplementary Table 5, https://links.lww.com/CM9/B719]. For patients with HR–/HER2+ and TNBC cancer, the proportions with four or more axillary lymph node metastases were 4.4% and 10.2%, respectively.[1,6] Combined with the conclusions of previous studies, for patients with cN1, HR-/HER2+, TNBC, and bpCR, as well as negative SLN patients, avoidance of ALND is acceptable. Since the proportion of patients with more than four positive SLNs is very low, the use of radiotherapy instead of ALND is likely safe for certain types of breast cancer patients. However, the results of the Alliance A011202 trial, more clinical data, and further prospective studies are necessary to ensure the accuracy of this conclusion. This study provides representative data for the treatment of women with breast cancer in real world China, which provides for increased generalization of the findings. However, it is important to note that axillary lymph node aspiration was not performed in some patients who received cN1 imaging assessment, which may affect pre-neoadjuvant N staging. With a decreasing number of contra-indications, the use of NAC in China has increased yearly. The rates of cT1-2N0, TNBC, and HR–/HER2+ patients with ypN0 were found to be very high. More prospective studies are needed to demonstrate whether these patients can be exempted from SLNB. Acknowledgments The authors acknowledge the member units of CSBrS for the data collection, Yangyu Zhang for the data analysis and Xiaoyun Mao for providing revisions to this manuscript. We thank International Science Editing (http://www.internationalscienceediting.com) for editing this manuscript. Funding This work was supported by a grant from the Beijing Medical Reward Foundation (No. YXJL-2016-0040-0012). Conflicts of interest None.

Objective To study the risk factors of febrile neutropenia（FN） after neoadjuvant therapy for early breast cancer and explore the short-term efficacy of neoadjuvant therapy. Methods The clinical data of early breast cancer patients undergone neoadjuvant therapy in Breast Disease Center of the Peking University First Hospital from January 1st 2018 to June 30th, 2022 were analyzed retrospectively. Results A total of 370 patients with early breast cancer underwent neoadjuvant therapy with different regiments, among which 32 cases developed FN, accounting for 8.6%.Clinicopathological analysis showed that FN was correlated with advanced age, the presence of background diseases, and the use of anthracene combined with taxanes（P＜0.05）. There was no significant difference in the proportion of FN after prophylactic use of long-acting or short-acting granulocytic stimulating factor（P=0.791）. There was no correlation between FN and pCR（P=0.497）. Conclusion In the case of prophylactic application of granulocytic stimulating factor,the incidence of FN in patients underwent neoadjuvant therapy was lower, the safety was better, and the operation time is not delayed.Patients who were elder than 65 years old, had background diseases and received the regimen with the combination of anthracene and taxanes were the main cause of FN. Prophylactic use of long-acting granulocytic stimulating factor did not reduce the incidence of FN compared with short-acting form.

Purpose The prediction of axillary lymph node status after neoadjuvant chemotherapy (NAC) becoming critical because of the advocation of the de-escalation of axillary management. We investigate associated factors of axillary upstaging in clinical node-negative(cN0) breast cancer patients receiving NAC to develop and validate an accurate prediction nomogram; Methods We retrospectively analyzed 2101 breast cancer patients with stage of cT1-3N0 treated by NAC and subsequent surgery between 2010 and 2020 in twenty hospitals across China. Patients randomly divided into a training set and validation set (3:1). Univariate and multivariate logistic regression analysis were performed, after which a nomogram was constructed and validated; Results In total, pathologic node negativity (ypN0) achieved in 1552 (73.9%) patients and another 549(26.1%) patients upstaged to pathologic node positive (ypN+). Breast pathologic complete response (bpCR) was achieved in 499 (23.8%) patients and non-bpCR in 1602 (76.3%) patients. A nomogram was established by ER, tumor histology, NAC regimen, cycle of NAC treatment, and the bpCR, which were confirmed by multivariate logistic analysis as independent predictors of nodal upstaging in the training cohort (n = 1576). The area under the receiver operating characteristic curve (AUC) of the training cohort and validation cohort were 0.74 (95%CI, 0.64–0.71) and 0.76 (95% CI, 0.63–0.75) respectively; Conclusion We present a nomogram with a nationwide large sample data which can effectively predict axillary upstaging after neoadjuvant chemotherapy to give better advice for individualized axillary lymph node management of breast cancer.

e13551 Background: We are building a clinical decision support system (CSCO AI) for breast cancer patients to improve the efficiency of clinical decision-making. We aimed to assess cancer treatment regimens, in neoadjuvant therapy, adjuvant chemotherapy, adjuvant endocrine therapy, first line therapy and second line therapy, given by CSCO AI and clinicians. Methods: 400 breast cancer patients were screened from the CSCO database. Clinicians with similar levels were randomly assigned one of the volumes (200 cases). After that, clinicians with guidelines were asked to answer the same cases again. CSCO AI was asked to assess all cases. Three reviewers were independently asked to evaluate the regimens from clinicians and CSCO AI. Regimens were masked before evaluation. The primary outcome was the proportion of high-level conformity (HLC), which were defined as the proportions of regimens in accordance with CSCO guidelines. Results: The overall concordance between clinicians and CSCO AI was 67.4% (2350/3500). After referring to the guideline, a total of 22.6% (792/3500) regimens were modified by clinicians, 12.9% (451/3500) had a higher grades and 9.7% (341/3500) had a lower grades. In early stage, the concordance was elevated with statistical significance from 71.3% (1497/2100) to 76.1% (1598/2100, p＜0.001). In the metastatic stage, the concordance was improved form 61.7% (864/1400) to 66.0% (924/1400, p=0.018). HLC in CSCO AI was 95.8% (95%CI:94.0%-97.6%), significantly higher than that in clinicians (90.8%, 95%CI:89.8%-91.8%) and in clinicians with guidelines (92.1%, 95%CI:91.0%-93.4%). In early stage, high-level conformity in CSCO AI was 95.7%, with no statistical significance when compared with clinicians (92.7%, p=0.078) and clinicians with guidelines (92.3%, p=0.050). In metastatic stage, high-level conformity in clinicians was only 88.0%, lower than that in CSCO AI (96.0%, p=0.001). However, after referring guidelines, high-level conformity in clinicians was elevated to 91.9%, with no significant difference when compared with that in CSCO AI (p=0.058). Considering professions, the high level conformity of surgeons was 85.9%, lower than that of CSCO AI (OR=0.25,95%CI: 0.16-0.41). The most significant difference in HLC was in first-line therapy (OR=0.06, 95%CI:0.01-0.41). When clinicians were divided according to their levels, there was no statistical significance between CSCO AI and higher-level clinicians. Conclusions: Clinical decision support for breast cancer was superior for most process outcomes except for second-line therapy. The improvements in process outcomes suggest that CSCO AI can be widely used in clinical practice.

Background:The Chinese Society of Breast Surgery (CSBrS) Practice Guideline 2021 was published nearly one year ago. The new guideline was revised based on comprehensive feedback of the previous publication. The aim is to provide a better reference suitable for Chinese breast surgeons.Methods:Referred to GRADE (Grading of Recommendations Assessment, Development and Evaluation) system, evidences accepted by the Guideline were classified into four categories: I, II, III and IV, which reflected the reliability of the evidences quantitatively. The guideline also comprehensively considered the accessibility of the guideline in clinical practice in China and gave recommendations with different strengths.Results:The guideline emphasized the basic idea that a curative surgical approach falls under the category of radical tumor surgery. Six chapters, including "Diagnosis and treatment of patients with invasive breast cancer", "Sentinel lymph node biopsy in patients with early-stage breast cancer", "Breast-conserving surgery in patients with early-stage breast cancer", "Modified radical mastectomy of breast cancer", "Central venous access for the systemic treatment of breast cancer", and "Breast cancer in pregnancy and postpartum breast cancer" were revised.Conclusions:Compared with the 2021 edition, the new guideline has been revised in six chapters based on the latest research evidence and clinical needs.

Abstract In this study, we aimed to explore the safety and vaccination coverage data of Chinese patients with breast cancer receiving coronavirus disease 2019 (COVID-19) vaccination. The patients were recruited from 41 hospitals across 20 Chinese provinces. The vaccination coverage was approximately 22.4%, and the frequency of total adverse events was 13.3% after the first dose and 9.9% after the second dose. The most frequent adverse reaction within 14 days of the first dose was local pain (5.7%). Unvaccinated patients were very likely to reject the vaccine rather than be hesitant in patients with old age (odds ratio [OR], 1.238; 95% confidence interval [CI], 1.101–1.391), chronic disease history (OR, 1.189; 95% CI, 1.057–1.337), and cancer relapse (OR, 1.398; 95% CI, 1.233–1.585). Of the unvaccinated patients with breast cancer, 54.1% opted to receive COVID-19 vaccines if more data were available. Considering the safety but low vaccination coverage for breast cancer, increased positive attitudes and acceptance toward COVID-19 vaccines are important.

Key Points Question What are the trends and disparities of treatment among women with early breast cancer in China and the US? Findings In this cross-sectional study of 57 720 patients with early breast cancer diagnosed from 2011 to 2021, patients in China were younger and had more late-stage and aggressive cancer subtypes. Of these, 69% of patients with ERBB2 (formerly HER2 or HER2/neu)-positive cancer received trastuzumab-based therapy after 2017 in China compared with 62% of patients in the US during the same period. Meaning These findings suggest that disparities in early breast cancer treatment between patients in China and patients in the US narrowed gradually from 2011 to 2021.