Improved Model for Predicting Axillary Response to Neoadjuvant Chemotherapy in Patients with Clinically Node-Positive Breast Cancer

Nomogram Based on US and Clinicopathologic Characteristics: Axillary Nodal Evaluation Following Neoadjuvant Chemotherapy in Patients With Node-Positive Breast Cancer

BACKGROUND

To develop a convenient modality to predict axillary response to neoadjuvant chemotherapy (NAC) in breast cancer patients.

MATERIALS AND METHODS

In this multi-center study, a total of 1019 breast cancer patients with biopsy-proven positive lymph node (LN) receiving NAC were randomly assigned to the training and validation groups at a ratio of 7:3. Clinicopathologic and ultrasound (US) characteristics of both primary tumors and LNs were used to develop corresponding prediction models, and a nomogram integrating clinicopathologic and US predictors was generated to predict the axillary response to NAC.

RESULTS

Axillary pathological complete response (pCR) was achieved in 47.79% of the patients. The expression of estrogen receptor, human epidermal growth factor receptor -2, Ki-67 score, and clinical nodal stage were independent predictors for nodal response to NAC. Location and radiological response of primary tumors, cortical thickness and shape of LNs on US were also significantly associated with nodal pCR. In the validation cohort, the discrimination of US model (area under the curve [AUC], 0.76) was superior to clinicopathologic model (AUC, 0.68); the combined model (AUC, 0.85) demonstrates strong discriminatory power in predicting nodal pCR. Calibration curves of the nomogram based on the combined model demonstrated that substantial agreement can be observed between the predictions and observations. This nomogram showed a false-negative rates of 16.67% in all patients and 10.53% in patients with triple negative breast cancer.

CONCLUSION

Nomogram incorporating routine clinicopathologic and US characteristics can predict nodal pCR and represents a tool to aid in treatment decisions for the axilla after NAC in breast cancer patients.

Accuracy of ultrasonographic changes during neoadjuvant chemotherapy to predict axillary lymph node response in clinical node-positive breast cancer patients

Purpose

To evaluate whether changes in ultrasound features during neoadjuvant chemotherapy (NAC) could predict axillary node response in clinically node-positive breast cancer patients.

Methods

Patients with biopsy-proven node-positive disease receiving NAC between February 2009 and March 2021 were included. Ultrasound (US) images were obtained using a 5-12-MHz linear array transducer before NAC, after two cycles, and at the completion of NAC. Long and short diameter, cortical thickness, vascularity, and hilum status of the metastatic node were retrospectively reviewed according to breast imaging-reporting and data system (BI-RADS). The included population was randomly divided into a training set and a validation set at a 2:1 ratio using a simple random sampling method. Factors associated with node response were identified through univariate and multivariate analyses. A nomogram combining clinical and changes in ultrasonographic (US) features was developed and validated. The receiver operating characteristic (ROC) and calibration plots were applied to evaluate nomogram performance and discrimination.

Results

A total of 296 breast cancer patients were included, 108 (36.5%) of whom achieved axillary pathologic complete response (pCR) and 188 (63.5%) had residual nodal disease. Multivariate regression indicated that independent predictors of node pCR contain ultrasound features in addition to clinical features, clinical features including neoadjuvant HER2-targeted therapy and clinical response, ultrasound features after NAC including cortical thickness, hilum status, and reduction in short diameter ≥50%. The nomogram combining clinical features and US features showed better diagnostic performance compared to clinical-only model in the training cohort (AUC: 0.799 vs. 0.699, P=0.001) and the validation cohort (AUC: 0.764 vs. 0.638, P=0.027).

Conclusions

Ultrasound changes during NAC could improve the accuracy to predict node response after NAC in clinically node-positive breast cancer patients.

Predicting pathological axillary lymph node status with ultrasound following neoadjuvant therapy for breast cancer

Purpose

High-performing imaging and predictive markers are warranted to minimize surgical overtreatment of the axilla in breast cancer (BC) patients receiving neoadjuvant chemotherapy (NACT). Here we have investigated whether axillary ultrasound (AUS) could identify axillary lymph node (ALN) metastasis (ALNM) pre-NACT and post-NACT for BC. The association of tumor, AUS features and mammographic density (MD) with axillary-pathological complete response (axillary-pCR) post-NACT was also assessed.

Methods

The NeoDense-study cohort (N = 202, NACT during 2014–2019), constituted a pre-NACT cohort, whereas patients whom had a cytology verified ALNM pre-NACT and an axillary dissection performed (N = 114) defined a post-NACT cohort. AUS characteristics were prospectively collected pre- and post-NACT. The diagnostic accuracy of AUS was evaluated and stratified by histological subtype and body mass index (BMI). Predictors of axillary-pCR were analyzed, including MD, using simple and multivariable logistic regression models.

Results

AUS demonstrated superior performance for prediction of ALNM pre-NACT in comparison to post-NACT, as reflected by the positive predictive value (PPV) 0.94 (95% CI 0.89–0.97) and PPV 0.76 (95% CI 0.62–0.87), respectively. We found no difference in AUS performance according to neither BMI nor histological subtype. Independent predictors of axillary-pCR were: premenopausal status, ER-negativity, HER2-overexpression, and high MD.

Conclusion

Baseline AUS could, to a large extent, identify ALNM; however, post-NACT, AUS was insufficient to determine remaining ALNM. Thus, our results support the surgical staging of the axilla post-NACT. Baseline tumor biomarkers and patient characteristics were predictive of axillary-pCR. Larger, multicenter studies are needed to evaluate the performance of AUS post-NACT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06283-8.

Targeted axillary biopsy and sentinel lymph node biopsy for axillary restaging after neoadjuvant chemotherapy

Purpose

Accurate restaging of the axilla after neoadjuvant chemotherapy (NAC) is an important issue to ensure deescalating axillary surgery in patients with initial metastatic nodes. We aimed to present our results of targeted axillary biopsy (TAB) combined with sentinel lymph node biopsy (SLNB) for axillary restaging after NAC.

Methods

In 64 breast cancer patients who underwent NAC, biopsy-proven positive nodes were marked with clips before NAC, and ultrasound-guided wire localization of clip-marked nodes was performed after NAC. Patients underwent TAB and SLNB for post-NAC axilla restaging.

Results

Identification rates of post-NAC TAB and SLNB were 98.4% and 87.5%, respectively (P = 0.033). Histopathology revealed a nodal pathologic complete response (pCR) rate of 47% in which axillary lymph node dissection (ALND) was avoided. TAB alone and SLNB alone detected residual disease in 29 (85.3%) and 20 (58.8%) patients (P = 0.029), respectively. Whereas rates of up to 97% had been achieved with a combination of TAB and SLNB. The pCR rates after NAC were 64.3% for human epidermal growth factor receptor 2 positive and triple-negative tumors and 13.6% in luminal tumors (P = 0.0002).

Conclusion

Pathologic analysis following TAB combined with SLNB revealed the pCR rates to NAC in a considerable number of patients that provided de-escalation of axillary surgery. A combination of SLNB and TAB was found to be an accurate procedure in establishing residual nodal disease. This combined procedure in patients with initially positive nodes was a reliable method for post-NAC axillary restaging.

A nomogram for predicting axillary pathologic complete response in hormone receptor-positive breast cancer with cytologically proven axillary lymph node metastases

BACKGROUND

The objective of this study was to determine an axillary pathologic complete response (pCR) and its influencing factors in patients with hormone receptor (HR)-positive breast cancer and cytologically proven axillary lymph node metastases. A prediction nomogram was established to provide information for the de-escalation of axillary management in these patients after neoadjuvant chemotherapy.

METHODS

The authors retrospectively enrolled all patients with HR-positive breast cancer in the neoadjuvant chemotherapy data set of Fudan University Shanghai Cancer Center. All data were prospectively collected. From 2007 to 2016, 533 consecutive patients were included. Multivariate logistic regression analysis was performed, after which a nomogram was constructed and validated.

RESULTS

An axillary pCR was achieved in 168 patients (31.5%), the which was much higher than the proportion of those who achieved a breast pCR (103 patients; 19.3%). Patients who had human epidermal growth factor receptor 2-positive disease (P = .004), a better primary tumor response (P = .001), earlier clinical stage (P = .045), and lower estrogen receptor expression (P < .001) were more likely to achieve a lymph node pCR. The nomogram indicated an area under the receiver operating characteristic curve (AUC) of 0.84 (95% CI, 0.78-0.89) in the training set. The validation set showed good discrimination with an AUC of 0.75 (95% CI, 0.69-0.81). The C-index was 0.834 and 0.756 in the training and validation cohort, respectively. The nomogram was well calibrated.

CONCLUSIONS

The authors developed and validated a nomogram for predicting axillary pCR in patients with HR-positive disease accurately by using clinicopathologic factors available before surgery. The model will facilitate logical clinical decision making and clinical trial design.

The Evolving Role of Marked Lymph Node Biopsy (MLNB) and Targeted Axillary Dissection (TAD) after Neoadjuvant Chemotherapy (NACT) for Node-Positive Breast Cancer: Systematic Review and Pooled Analysis

Simple Summary

The 5-year survival rate for patients with breast cancer, in whom disease has spread to local lymph nodes, is 85%. However, many live with the complications of surgery to remove the lymph nodes in the armpit thus impacting their quality of life. In recent years, new approaches have been developed to minimise surgery and reduce complications. The aim of this systematic review was to assess the feasibility and accuracy of two minimally invasive surgical procedures, Marked Lymph Node Biopsy and Targeted Axillary Dissection as an alternative to complete removal of the axillary lymph nodes after upfront chemotherapy in patients in whom cancer spread to the regional lymph nodes. Our findings confirm that these procedures can safely replace more radical surgery in women who have responded well to upfront drug treatment. Therefore, although further research to determine long-term outcomes is required, this review concludes that it is reasonable to offer such patients the option of less invasive surgery thus avoiding over treatment and enhancing quality of life.

Abstract

Targeted axillary dissection (TAD) is a new axillary staging technique that consists of the surgical removal of biopsy-proven positive axillary nodes, which are marked (marked lymph node biopsy (MLNB)) prior to neoadjuvant chemotherapy (NACT) in addition to the sentinel lymph node biopsy (SLNB). In a meta-analysis of more than 3000 patients, we previously reported a false-negative rate (FNR) of 13% using the SLNB alone in this setting. The aim of this systematic review and pooled analysis is to determine the FNR of MLNB alone and TAD (MLNB plus SLNB) compared with the gold standard of complete axillary lymph node dissection (cALND). The PubMed, Cochrane and Google Scholar databases were searched using MeSH-relevant terms and free words. A total of 9 studies of 366 patients that met the inclusion criteria evaluating the FNR of MLNB alone were included in the pooled analysis, yielding a pooled FNR of 6.28% (95% CI: 3.98–9.43). In 13 studies spanning 521 patients, the addition of SLNB to MLNB (TAD) was associated with a FNR of 5.18% (95% CI: 3.41–7.54), which was not significantly different from that of MLNB alone (p = 0.48). Data regarding the oncological safety of this approach were lacking. In a separate analysis of all published studies reporting successful identification and surgical retrieval of the MLN, we calculated a pooled success rate of 90.0% (95% CI: 85.1–95.1). The present pooled analysis demonstrates that the FNR associated with MLNB alone or combined with SLNB is acceptably low and both approaches are highly accurate in staging the axilla in patients with node-positive breast cancer after NACT. The SLNB adds minimal new information and therefore can be safely omitted from TAD. Further research to confirm the oncological safety of this de-escalation approach of axillary surgery is required. MLNB alone and TAD are associated with acceptably low FNRs and represent valid alternatives to cALND in patients with node-positive breast cancer after excellent response to NACT.

Nomogram for predicting axillary lymph node status after neoadjuvant chemotherapy in breast cancer

BACKGROUND

Many breast cancer patients benefit from neoadjuvant chemotherapy (NAC). However, sentinel lymph node biopsy (SLNB) after NAC remains controversial, especially for patients with axillary lymph node metastasis (ALNM) at diagnosis. We developed a nomogram for predicting axillary lymph node (ALN) status after NAC to screen for patients for whom SLNB may be beneficial.

METHODS

A total of 320 cT1-4N0-1M0 breast cancer patients receiving ALN dissection (ALND) after NAC were included. Univariate and multivariate logistic regression analyses determined significant factors for predicting ALN status. Efficacy of the resulting nomogram was assessed using receiver operating characteristic (ROC) and calibration curves, while decision curve analysis (DCA) was used to evaluated net clinical benefit. Our nomogram was validated using female patients grouped according to a diagnosis of node-positive (cN1) or node-negative (cN0) by ultrasound-guided needle biopsy of suspected lymph nodes before NAC.

RESULTS

Logistic regression analyses indicated that estrogen receptor (ER), Ki67, degree of tumor regression, clinical tumor T stage after NAC, and ALN Breast Imagining-Reporting and Data System (BI-RADS) category after NAC, were associated with ALN status. The resulting nomogram had an area under the curve (AUC) of 0.802 [95% confidence interval (CI), 0.7485-0.8554], and the calibration plot showed strong uniformity between predicted and actual ALN status. DCA indicated a positive net benefit of nomogram predictions in our cohort. After internal validation, the cN1 and cN0 groups had an AUC of 0.7926 (95% CI, 0.7187-0.8665) and 0.8165 (95% CI, 0.7381-0.8949), respectively. The calibration plot indicated better performance in the cN0 group.

CONCLUSIONS

After NAC, some patients may benefit from SLNB. Our nomogram predicts ALN status after NAC and has great potential to assist in clinical decision-making.

Efficacy of neoadjuvant endocrine therapy compared with neoadjuvant chemotherapy in pre-menopausal patients with oestrogen receptor-positive and HER2-negative, lymph node-positive breast cancer

Introduction

Neoadjuvant endocrine therapy (NET) has demonstrated efficacy in post-menopausal patients with hormone-responsive breast cancer. This trial was designed to compare the efficacy of neoadjuvant chemotherapy (NCT) with NET in pre-menopausal breast cancer.

Patients and methods

In this prospective, randomised, phase III study, oestrogen receptor (ER)-positive, HER2-negative, and lymph node-positive pre-menopausal breast cancer patients were recruited from 7 hospitals in South Korea. Enrolled patients were randomly assigned (1:1) to receive 24 weeks of either NCT or NET with goserelin and tamoxifen. The primary purpose was to evaluate the non-inferiority of NET compared to NCT using clinical response, assessed by MRI. Besides, pathological complete response rate (pCR), changes in Ki-67 expression, breast conservation surgery (BCS) rate, and quality of life were included as secondary endpoints.

Results

A total of 187 patients were assigned to receive NCT (n = 95) or NET (n = 92), and 87 patients in each group completed treatments. More NCT patients had complete response or partial response than NET patients using MRI (NCT 83.7% vs. NET 52.9%, 95% CI 17.6–44.0, p < 0.001) and callipers (NCT 83.9% vs. NET 71.3%, 95% CI 0.4–24.9, p = 0.046). Three NCT patients (3.4%) and one NET patient (1.2%) showed pCR (p < 0.005). No difference existed in the conversion rate of BCS (13.8% for NCT vs. 11.5% for NET, p = 0.531) and Ki-67 change (p = 0.114) between the two groups. Nineteen NCT patients had treatment-related grade 3 or worse events compared with none in the NET group.

Conclusions

Better clinical responses were observed in pre-menopausal patients after 24 weeks of NCT compared to those observed after NET.

Trial registration

Clinicaltrials.gov, NCT01622361. Registration June 19, 2012.

Axillary Nodal Evaluation in Breast Cancer: State of the Art

Axillary lymph node (LN) metastasis is the most important predictor of overall recurrence and survival in patients with breast cancer, and accurate assessment of axillary LN involvement is an essential component in staging breast cancer. Axillary management in patients with breast cancer has become much less invasive and individualized with the introduction of sentinel LN biopsy (SLNB). Emerging evidence indicates that axillary LN dissection may be avoided in selected patients with node-positive as well as node-negative cancer. Thus, assessment of nodal disease burden to guide multidisciplinary treatment decision making is now considered to be a critical role of axillary imaging and can be achieved with axillary US, MRI, and US-guided biopsy. For the node-positive patients treated with neoadjuvant chemotherapy, restaging of the axilla with US and MRI and targeted axillary dissection in addition to SLNB is highly recommended to minimize the false-negative rate of SLNB. Efforts continue to develop prediction models that incorporate imaging features to predict nodal disease burden and to select proper candidates for SLNB. As methods of axillary nodal evaluation evolve, breast radiologists and surgeons must work closely to maximize the potential role of imaging and to provide the most optimized treatment for patients.

Axillary ultrasound for prediction of response to neoadjuvant therapy in the context of surgical strategies to axillary dissection in primary breast cancer: a systematic review of the current literature

PURPOSE

Data on the optimal treatment strategy for patients undergoing neoadjuvant therapy (NAT) who initially presented with metastatic nodes and convert to node-negative disease (cN+ → ycN0) are limited. Since NAT leads to axillary downstaging in 20-60% of patients, the question arises whether these patients might be offered less-invasive procedures than axillary dissection, such as sentinel node biopsy or targeted removal of lymph nodes marked before therapy.

METHODS

We performed a systematic review of clinical studies on the use of axillary ultrasound for prediction of response to NAT and ultrasound-guided marking of metastatic nodes for targeted axillary dissection.

RESULTS

The sensitivity of ultrasound for prediction of residual node metastasis was higher than that of clinical examination and MRI/PET in most studies; specificity ranged in large trials from 37 to 92%. The diagnostic performance of ultrasound after NAT seems to be associated with tumor subtype: the positive predictive value was highest in luminal, the negative in triple-negative tumors. Several trials evaluated the usefulness of ultrasound for targeted axillary dissection. Before NAT, nodes were most commonly marked using ultrasound-guided clip placement, followed by ultrasound-guided placement of a radioactive seed. After chemotherapy, the clip was detected on ultrasound in 72-83% of patients; a comparison of sonographic visibility of different clips is lacking. Detection rate after radioactive seed placement was ca. 97%.

CONCLUSION

In conclusion, ultrasound improves prediction of axillary response to treatment in comparison to physical examination and serves as a reliable guiding tool for marking of target lymph nodes before the start of treatment. High quality and standardization of the examination is crucial for selection of patients for less-invasive surgery.

Predicting Axillary Response to Neoadjuvant Chemotherapy: Breast MRI and US in Patients with Node-Positive Breast Cancer

Background In patients who are expected to achieve axillary pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC), omission of axillary lymph node (LN) dissection could prevent morbidity and complications. Purpose To develop a clinical model to predict residual axillary LN metastasis in patients with clinically node-positive breast cancer after NAC by using MRI and US. Materials and Methods In this retrospective study, women with clinically node-positive breast cancer who were treated with NAC following surgery between January 2015 and September 2017 were included. The patients were randomly assigned to a test and validation set (7:3 ratio). Univariable and multivariable logistic regression analyses were performed to evaluate the independent predictors of residual axillary LN metastasis in the test set. A prediction risk score was developed based on the odds ratios from the multivariable analysis and validated in both sets. Results A total of 408 women were included (mean age ± standard deviation, 47.9 years ± 9.6). The axillary pCR rate was 56.6% (231 of 408). Independent predictors of residual axillary LN metastasis were clinical stage N2 or N3, presence of axillary lymphadenopathy at US after NAC, tumor size reduction less than 50% at MRI, Ki-67 negativity, hormone receptor positivity, and human epidermal growth factor receptor 2 negativity (all, P < .05). In a model using these predictors, the area under the receiver operating characteristic curve in the test and validation sets was 0.84 (95% confidence interval: 0.79, 0.88) and 0.78 (95% confidence interval: 0.70, 0.87), respectively. When the patients had a simplified risk score of 1, the false-negative rates ranged between 5%-10%. Conclusion A prediction model incorporating nodal status stage, US finding, MRI response, and molecular receptor status shows good diagnostic performance for residual axillary lymph node metastasis after neoadjuvant chemotherapy in patients with clinically node-positive breast cancer. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Whitman in this issue.

Does Tumor Size Predict Response to Neoadjuvant Chemotherapy in the Modern Era of Biologically Driven Treatment? A Nationwide Study of US Breast Cancer Patients

BACKGROUND

Tumor size has historically been used to stage breast cancer and guide treatment recommendations. The importance of tumor biology in long-term outcomes is increasingly being acknowledged. No large studies have examined the relative roles of tumor size and receptor status on response to neoadjuvant chemotherapy (NAC) in breast cancer.

PATIENTS AND METHODS

The National Cancer Database was queried for women who underwent NAC and surgery for unilateral clinical stage I to III (cT1-3) invasive breast cancer from 2010 to 2013. Multivariable logistic regression models were used to assess the relation between receptor status, tumor size, and pathologic complete response (pCR) while controlling for other biologic, sociodemographic, diagnosis, and treatment factors.

RESULTS

We included 38,864 women in this study, most presented with cT2 disease (55%). Patients predominantly had estrogen receptor (ER)/progesterone receptor (PR)-positive (ER/PR⁺) HER2^- (45%) or ER/PR^- HER2^- (28%) disease. Nineteen percent (7432 patients) had a pCR. cT3 (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.59-0.70) but not cT2 cancers (OR, 0.95; 95% CI, 0.89-1.02) were associated with lower pCR rates compared with cT1 disease. HER2⁺ (ER/PR⁺ HER2⁺: OR, 2.94; 95% CI, 2.72-3.18; ER/PR^- HER2⁺: OR, 6.45; 95% CI, 5.92-7.02) and ER/PR^- HER2^- cancers (OR, 3.94; 95% CI, 3.68-4.22) were more likely to experience pCR than those with ER/PR⁺ HER2^- cancers. Receptor status was more strongly associated with pCR than tumor size.

CONCLUSION

Tumor size is independently associated with pCR after NAC after controlling for receptor status, although the effect of receptor status is stronger. These data reinforce the importance of receptor status as well as tumor size, each of which might act as surrogates for tumor biology, in setting expectations for outcomes in patients who undergo NAC.

Multiparametric MR imaging to assess response following neoadjuvant systemic treatment in various breast cancer subtypes: Comparison between different definitions of pathologic complete response

OBJECTIVES

To validate the performance of multiparametric magnetic resonance (MR) imaging to assess pathologic response to neoadjuvant systemic therapy (NST) in various breast cancer subtypes considering two definitions of pCR: absence of any residual invasive cancer or DCIS (ypT0) and absence of invasive tumour cells (ypT0/is).

METHODS

Institutional review board-approved retrospective study, with waiver of the need to obtain informed consent. From January 2015 to June 2017, 81 women with 82 breast cancers undergoing NST were included. Eighteen lesions (22%) were immunohistochemically HER2-positive, 12 (15%) triple negative (TN), 42 (51%) luminal B-like and 10 (12%) luminal B-like/HER2-positive. Breast MR imaging was performed before and after NST. A comparative analysis considering pCR as ypT0 and ypT0/is was carried out. Performance of univariate and multivariate models to potentially predict pathologic response were evaluated.

RESULTS

ypT0 was attained in 23% (19/82) of cases and ypT0/is in 33% (27/82) of cases. In both scenarios, HER2-positive subtype achieved the best response, 53% and 48%, respectively. A significant relationship was found between late enhancement and pathologic response (p < 0.001) regardless of pCR definition. In the ypT0 scenario, mean ADC ratio in the pCR subgroup was significantly higher than that in the non-pCR subgroup (p = 0.021) but no significant relationship was noted in ypT0/is. A multivariate model including MR late enhancement, ADC ratio and tumor subtype identified pathologic response with 86% and 84% accuracy when ypT0 and ypT0/is were considered, respectively.

CONCLUSION

MR imaging late enhancement and ADC ratio along with breast cancer IHC subtype identify pathologic response following NST with high accuracy, achieving the highest NPV in TN and HER2-positive tumors and the highest PPV in luminal B-like subtypes, regardless of the definition of pCR as ypT0 or ypT0/is. In light of these findings and given that residual DCIS does not have an impact on survival rates, ypT0/is seems to be the preferable definition of pCR.

Axillary Pathologic Complete Response to Neoadjuvant Chemotherapy in Clinically Node-Positive Breast Cancer Patients: A Predictive Model Integrating the Imaging Characteristics of Ultrasound Restaging with Known Clinicopathologic Characteristics

The goal of this study was to evaluate various clinicopathologic and imaging characteristics as independent predictors of axillary pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) and to determine the added value of a model that integrates imaging characteristics of ultrasound (US) restaging with known clinicopathologic characteristics. A total of 227 clinically node-positive breast cancer patients underwent axillary US after NAC (termed US restaging) before surgery. We constructed a clinicopathologic model with independent predictors of clinicopathologic characteristics in multivariate analyses. A combined model was created by integrating imaging characteristics with clinicopathologic characteristics. The predictive values of the models were compared using the area under the receiver operating characteristic curve. Of the 227 patients, 106 (46.7%) achieved axillary pCR. Multivariate analysis revealed that higher histologic grades (odds ratio [OR] = 4.21 and 10.11 for moderate and high grade, respectively), negative hormonal receptor status (OR = 2.88), smaller (≤1.5 cm) residual tumor size (OR = 2.83), absence of fatty hilum loss (OR = 14.06) and absence of eccentric cortical thickening of the axillary lymph node (OR = 4.42) were independently associated with the axillary pCR (all p values < 0.05). Integrating the imaging characteristics of the US restaging significantly increased the predictive capability of the model that applied only the clinicopathologic characteristics (c-index, 0.783 vs. 0.657; p < 0.001). Imaging characteristics of the US restaging were independently associated with axillary pCR after NAC and they significantly improved the predictive capability of the model that used only the clinicopathologic characteristics.