To compare automated breast ultrasound (ABUS) and handheld breast ultrasound (HHUS) as adjuncts to digital mammography (DM) for preoperative assessment of local tumor extent in women with newly diagnosed early-stage breast cancer. In this prospective study conducted at three institutions, women with newly diagnosed early-stage breast cancer and no palpable axillary nodes scheduled for surgery underwent ABUS and HHUS adjunct to DM between Oct 2019 and Apr 2021. The primary outcome was the sensitivity of ABUS with DM (ABUS/DM) and HHUS with DM (HHUS/DM) for detecting additional ipsilateral or contralateral cancers beyond the index cancer. ABUS/DM was evaluated for noninferiority with a prespecified margin of 5

The clinical significance of residual mammographic microcalcifications after neoadjuvant systemic therapy in human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer remains unclear. Traditionally, persistent calcifications have prompted wide excisions or mastectomies under the assumption that they indicate residual disease. However, accumulating evidence suggests that calcifications may persist as treatmentrelated or biologically-attenuated changes, rather than as viable carcinomas, particularly in the era of dual HER2-directed therapy. Recent Korean studies demonstrate that patients with favorable radiologic response who achieve pathologic complete response maintain excellent local control after breast-conserving surgery, even when residual calcifications are present. A large multicenter cohort study reported a 5-year local recurrence-free survival rate of 97.4% and a validated prediction model showed strong discriminatory performance. This Brief Communication synthesizes emerging evidence on the biological basis and clinical implications of residual calcifications after neoadjuvant therapy, with emphasis on recent Korean data. Current evidence supports a response-adapted surgical approach in selected patients, emphasizing clip-guided excision of the invasive index lesion and consistent delivery of whole-breast irradiation rather than routine removal of the entire pretreatment calcification field in patients with HER2+ breast cancer. Prospective validation with a longterm follow-up is warranted to further refine patient selection and confirm the safety of this strategy in clinical practice.

OBJECTIVE:To evaluate the performance of supplemental automated breast ultrasound (ABUS) added to mammography-based breast cancer screening for women with nondense breasts. MATERIALS AND METHODS:A retrospective search of radiology databases at two tertiary institutions identified asymptomatic women with nondense breasts who underwent breast cancer screening using both digital mammography (DM) and supplemental ABUS between January 2020 and December 2023. We excluded women without sufficient follow-up data or those without an established final diagnosis, including histopathologic results. The performance measures of DM alone and ABUS combined with DM (ABUS plus DM) were compared. The primary outcome was the cancer detection rate (CDR), and the secondary outcomes were sensitivity and specificity. Subgroup analyses were performed for women with scattered fibroglandular density and almost entirely fatty breasts. RESULTS:A total of 2,904 pairs of screening examinations were performed in 1,683 women (59 ± 10 years), detecting 26 cancers. In comparison with DM alone, ABUS plus DM showed higher CDR (9.0 vs. 7.9 per 1,000 examinations, P < 0.001), higher sensitivity (100% [26/26] vs. 88.5% [23/26], P < 0.001), and lower specificity (95.0% [2,735/2,878] vs. 97.9% [2,817/2,878], P < 0.001). In women with scattered fibroglandular density, ABUS increased the CDR from 7.4 to 8.5 per 1,000 examinations and improved the sensitivity from 87.0% [20/23] to 100% [23/23] (P < 0.001). In women with almost entirely fatty breasts, ABUS plus DM showed the same CDR (16.4 per 1,000 examinations) and sensitivity (100% [3/3]) as DM alone. Three cancers (11.5% [3/26]), all of which were stage T1N0, were detected only by supplemental ABUS. CONCLUSION:Supplemental ABUS improved cancer detection and sensitivity in women with nondense breasts, with the benefits primarily observed in those with scattered fibroglandular density.

PURPOSE:The prognostic relevance of the detection mode for regional lymph node recurrence (LNR) remains unclear. We aimed to identify the risk factors associated with isolated regional LNR and to evaluate the impact of the mode of detection on distant metastasis-free survival (DMFS) and overall survival (OS). METHODS:This retrospective cohort study included women who underwent surgery for stage I-III invasive breast cancer between January 2011 and December 2019, with follow-up until December 2024. Isolated regional LNR was categorized according to the detection method (imaging vs. symptoms). Risk factors were identified using the Fine-Gray sub-distribution hazard model, and DMFS and OS were compared using Kaplan-Meier analysis and log-rank tests. RESULTS:Among 13,406 women (median age, 49 years; range, 20-87 years), 126 (0.9%) developed isolated regional LNR during a median follow-up of 6.3 years. Of these, 118 (93.7%) were detected through imaging and 8 (6.3%) through symptoms. Independent risk factors for isolated regional LNR included higher T stages (T2: hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.11-2.64; T3: HR, 3.08; 95% CI, 1.68-5.65), higher N stages (N2: HR, 2.97; 95% CI, 1.54-5.75; N3: HR, 3.12; 95% CI, 1.36-7.13), triple-negative subtype (HR, 1.71; 95% CI, 1.09-2.67), and omission of adjuvant radiotherapy (HR, 4.35; 95% CI, 2.86-6.67). Radiological patterns varied by detection, with ultrasound usually detecting level I nodes (51.6%) and computed tomography detecting internal mammary nodes (58.1%). Symptom-detected recurrence frequently occurred in the supraclavicular region (50.0%). Symptom-detected LNRs were associated with significantly worse DMFS (p < 0.05) than imaging-detected LNRs; however, OS did not differ between the groups. CONCLUSION:The detection mode was associated with DMFS, but not OS, suggesting that long-term outcomes are driven more by disease biology than by how recurrence is detected.

Background/Objectives: Breast adenoid cystic carcinoma (ACC) is a rare tumor with limited data on imaging features and treatment response. This study investigated the clinical and radiological characteristics of ACC of the breast. Methods: Patients with ACC who underwent surgery at our institution between February 2010 and December 2023 were included. Clinical characteristics, biopsy and surgical pathology findings, and follow-up outcomes were reviewed. Preoperative mammography, ultrasound (US), and MRI findings were analyzed. Results: Twenty-eight women (mean age, 57 ± 8 years) were identified. Half presented with palpable masses, and the remainder were detected on screening. Percutaneous biopsy was performed in 27 patients, correctly diagnosing ACC in 18 (66.7%), whereas 9 (33.3%) were misdiagnosed as having invasive ductal carcinoma. The mean tumor size was 2.9 cm (range, 0.9-8 cm), with axillary metastasis in two women (7.1%). Most tumors were triple-negative (78.6%), while six showed low estrogen-receptor positivity (<10%). Ki-67 was <20% in 64.3%, with no high values (≥75%). Three patients received neoadjuvant chemotherapy, with two non-responders. No recurrences occurred during a median follow-up of 51 months. Imaging revealed masses on mammography (85.2%), US (92.9%), and MRI (92.3%), with calcifications in two cases. Most lesions were highly suspicious (BI-RADS 4C or 5) and showed increased vascularity in 92.3% on Doppler US. Conclusions: Breast ACC typically presents as a hypervascular, highly suspicious mass. Despite frequent triple-negative profiles, it shows low proliferation, poor response to chemotherapy, and favorable prognosis.

OBJECTIVE:To investigate whether breast tissue composition on preoperative automated breast ultrasound (ABUS) is associated with the accuracy of cancer multiplicity evaluation and postoperative recurrence-free survival (RFS) in patients with early-stage breast cancer. MATERIALS AND METHODS:This retrospective analysis included women with early-stage breast cancer (clinical Tis, T1-2/N0) who underwent ABUS and digital mammography (DM) between October 2019 and April 2021. Tissue composition on ABUS was assessed using the Breast Imaging Reporting and Data System background echotexture (BE) (homogeneous-fat, homogeneous-fibroglandular, or heterogeneous). In a subgroup of patients with mammographically dense breasts, the glandular tissue component (GTC) on ABUS were further stratified into high (moderate or marked) or low (minimal or mild). Multivariable logistic and Cox regression analyses were used to identify factors associated with accurate cancer multiplicity categorization (unifocal, multifocal/multicentric, or bilateral) using ABUS + DM, and with RFS, respectively. RESULTS:Among 409 women (mean age ± standard deviation, 50.2 ± 8.7 years), ABUS combined with DM yielded accurate cancer multiplicity categorization in 368 patients (90.0%). Neither BE nor GTC on ABUS affected the accuracy of categorization when ABUS was combined with DM. Over a median postoperative follow-up of 3.5 years, 11 recurrences occurred. Heterogeneous BE on ABUS (hazard ratio [HR] 11.24 [95% confidence interval [CI]: 2.82-44.92]; P = 0.001), BRCA mutation (HR 15.94 [2.47-102.97]; P = 0.004), and pathologic index cancer size (HR per 1-cm increase 1.91 [1.13-3.23]; P = 0.02) was independently associated with RFS. In patients with dense breasts, heterogeneous BE (HR 14.17 [95% CI: 2.69-74.60]; P = 0.002) and high GTC (HR 10.32 [2.35-45.28]; P = 0.002) on ABUS, BRCA mutation (HR 24.34 [2.75-215.06]; P = 0.004), and pathologic cancer size (HR per 1-cm increase 2.62 [1.50-4.59]; P = 0.001) was independently associated with RFS. CONCLUSION:In patients with early-stage breast cancer, heterogeneous BE and high GTC on preoperative ABUS, along with larger cancer size and BRCA mutation, was associated with worse RFS. However, BE and GTC did not affect cancer multiplicity evaluation when ABUS was used in combination with DM.

OBJECTIVE:To compare the outcomes of imaging methods (mammography alone, ultrasound [US] alone, mammography combined with US, and magnetic resonance imaging [MRI]-based examination) for surveillance during the first 5 years after breast cancer surgery. MATERIALS AND METHODS:This retrospective cohort study analyzed the medical records of patients who underwent breast cancer surgery at a single institution between January 2011 and December 2015. Imaging surveillance was performed at 6-month or 1-year intervals during the first 5 years. RESULTS:A total of 6371 women (median age, 49 years; age range, 20-90 years) underwent 28199 mammograms, 42759 US, and 2619 MRI examinations. Of 172 second breast cancer diagnoses, 19 (11.0%) were interval cancers. Mammography combined with US demonstrated higher cancer detection rate (CDR) compared to mammography alone (odds ratios [OR] = 3.31, 95% confidence interval [CI]: 1.52-8.96, P = 0.009) and US alone (OR = 2.80, 95% CI: 1.71-4.65, P < 0.001), whereas there was no statistical significance when compared with MRI-based examinations (OR = 0.89, 95% CI: 0.49-1.74, P > 0.999). A statistically significant interaction was observed between the mammographic breast density (MBD) and CDR of the imaging methods (P for interaction = 0.003). CONCLUSION:The CDR of surveillance mammography combined with US was comparable with that of MRI-based examinations in an intensive surveillance setting. Considering the significant interaction between MBD and the CDR, a tailored approach for surveillance based on breast density is warranted.

Background/Objectives: We analyzed clinical and radiological characteristics and prognostic factors specific to young patients with breast cancer (YBC) aged <30 years. Methods: This retrospective study included 132 women aged <30 years who underwent breast surgery between 2008 and 2013. The clinical and radiological findings of the patients were examined and compared according to recurrence or death status at follow-up. Disease-free survival (DFS) and overall survival (OS) rates were also assessed. Results: Most patients (mean age, 27.1 years) presented with palpable lesions (85.6%). Hormone receptor-positive/human epidermal growth factor receptor-negative cancer was the most common molecular subtype (59.8%), followed by triple-negative breast cancer (28.0%), with high Ki-67 expression (62.1%). Mammography and ultrasound detected abnormalities in 90.1% and 97.3% of patients, respectively, whereas magnetic resonance imaging detected abnormalities in all patients. During the follow-up period (8–10 years), 28.5% of the patients experienced recurrence and 11.5% died. The calculated DFS and OS at 5 years were 80.8% and 69.8% and 91.3% and 87.8% at 10 years, respectively. Statistically significant factors associated with DFS/OS included the BRCA1 gene mutation, with preoperative neoadjuvant chemotherapy, no hormone therapy, larger tumor size, negative hormone receptor status, high Ki-67 expression, and some radiological findings, including asymmetry with calcifications on mammography, no sonographic echogenic rind of mass, and mild vascularity on Doppler study. Conclusions: Our study highlights the aggressive nature of breast cancer in YBC aged <30 years, with relatively high rates of recurrence and mortality. Significant factors affecting prognosis may guide personalized treatment approaches and predict the prognosis.

Background The optimal surgical management of human epidermal growth factor receptor 2 (HER2)-positive breast cancer with calcifications remains controversial, particularly when pathologic complete response (pCR) is suspected. Purpose To identify factors associated with pCR after neoadjuvant chemotherapy in patients with HER2-positive breast cancer and assess whether calcifications affect the performance of radiologic complete response (rCR) at MRI for predicting pCR. Materials and Methods This retrospective study included patients with HER2-positive breast cancer who received neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab and underwent surgery between January 2021 and October 2023. The association of clinicopathologic factors and imaging features at mammography and MRI with pCR was analyzed using logistic regression. The diagnostic performance of rCR at MRI for predicting pCR was compared between patients with and without calcifications using the χ2 test. Results Among the 732 patients included (mean age, 51.9 years ± 10.3 [SD]), 64.8% (474 of 732) had calcifications, 47.0% (344 of 732) had rCR at MRI, and 41.1% (301 of 732) had pCR. The factors associated with pCR included the estrogen receptor-low subtype (odds ratio [OR], 3.07 [95% CI: 1.31, 7.21]; P = .006), the hormone receptor-negative subtype (OR, 3.28 [95% CI: 2.16, 4.98]; P < .001), absence of calcifications (OR, 1.65 [95% CI: 1.15, 2.37]; P = .006), and rCR at MRI (OR, 7.33 [95% CI: 5.18, 10.38]; P < .001). The pCR rate and positive predictive value (PPV) of rCR at MRI were lower in patients with calcifications than in patients without calcifications (pCR, 37.1% vs 48.4%, P = .003; PPV, 60.0% vs 73.1%, P = .01). When the pCR definition was broadened from ypT0 to ypT0/Tis, there was no evidence of a difference in pCR rate between patients with and without calcifications (62.0% vs 58.5%; P = .35). Conclusion In patients with HER2-positive breast cancer, the absence of calcifications was associated with a higher pCR rate and a higher PPV for rCR at MRI for predicting pCR. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Grimm in this issue.

Purpose: The study investigated whether incorporating magnetic resonance imaging (MRI) alongside ultrasonography (US) in the preoperative evaluation is associated with differing survival outcomes between male and female breast cancer patients in a matched analysis. Additionally, clinicopathological prognostic factors were analyzed.Methods: Between January 2005 and December 2020, 93 male and 28,191 female patients who underwent breast surgery were screened. Exact matching analysis was conducted for age, pathologic T and N stages, and molecular subtypes. The clinicopathological characteristics and preoperative imaging methods of the matched cohorts were reviewed. Disease-free survival (DFS) and overall survival (OS) were assessed using Kaplan-Meier analysis, and Cox proportional hazards regression analysis was used to identify prognostic factors.Results: A total of 328 breast cancer patients (61 men and 267 women) were included in the matched analysis. Male patients had worse DFS (10-year DFS, 70.6% vs. 89.2%; P=0.001) and OS (10-year OS, 64.4% vs. 96.3%; P<0.001) than female patients. The pathologic index cancer size (hazard ratio [HR], 2.013; 95% confidence interval [CI], 1.063 to 3.810; P=0.032) was associated with worse DFS, whereas there were no significant factors associated with OS. Adding MRI to US for preoperative evaluation was not associated with DFS (HR, 1.117; 95% CI, 0.223 to 5.583; P=0.893) or OS (HR, 1.529; 95% CI, 0.300 to 7.781; P=0.609) in male patients.Conclusion: Adding breast MRI to US in the preoperative evaluation was not associated with survival outcomes in male breast cancer patients, and the pathologic index cancer size was associated with worse DFS.

To investigate whether digital mammography (DM) with artificial intelligence-based computer-aided diagnosis (AI-CAD) predicts pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in human epidermal growth factor receptor 2 (HER2)-positive and triple-negative (TN) breast cancers and compare performance with dynamic contrast–enhanced (DCE)-MRI. In this single-center study, patients who underwent NAC and surgery for HER2-positive or TN cancers between September 2020 and August 2021 were retrospectively selected to develop prediction models for pCR after NAC. From a prospective ASLAN (Avoid axillary Sentinel Lymph node biopsy After Neoadjuvant chemotherapy) trial, HER2-positive and TN cancer patients who underwent NAC and surgery between December 2021 and July 2022 were prospectively selected for model validation. Clinical-pathologic data and DM and MRI scans were obtained before and after NAC. Logistic regression analyses identified factors associated with pCR for model development and four models (clinical-pathologic, MRI, DM-AI-CAD, and combined) were evaluated. A total of 259 women (mean age, 53 years ± 10.5 [SD]) constituted the development cohort and 119 (50.8 years ± 11.1) the validation cohort. Age, clinical N stage, estrogen receptor, progesterone receptor, and Ki-67 were incorporated into the clinical-pathologic model. In the validation cohort, the DM-AI-CAD model, applying AI-CAD score ≤ 16 on post-NAC DM as the radiologic CR criterion, showed a higher area under the receiver operating characteristic curve (AUC) compared to the clinical-pathologic model (0.72 vs. 0.62; p = 0.01) for pCR. However, the MRI model showed the highest AUC (0.83), then the combined model (0.78). The model utilizing post-NAC DM with AI-CAD score ≤ 16 predicted pCR more accurately than the clinical-pathologic model in HER2-positive and TN cancers but was inferior to the MRI model. Question The performance of digital mammography (DM) with AI-based computer-aided diagnosis (AI-CAD) for predicting pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) is unclear. Findings The DM-AI-CAD model incorporating AI-CAD score ≤ 16 on post-NAC DM predicted pCR more accurately than the clinical-pathologic model but not the MRI model. Clinical relevance The DM-AI-CAD model has potential to predict pCR after NAC in breast cancer patients for whom MRI is unavailable or contraindicated.

PURPOSE:Evaluating the role of preoperative axillary ultrasound (US) in early-stage, clinically node-negative breast cancer, focusing on its ability to predict nodal metastasis and long-term recurrence. METHODS:This retrospective study included patients with T1-T2 clinically node-negative breast cancer who underwent preoperative axillary US and surgery between January and December 2009. Based on US findings, patients were classified as US-positive (presence of suspicious nodes, such as cortical thickening or absent fatty hilum) or US-negative. Clinicopathological features and recurrence outcomes were analyzed using the χ² test, Cox proportional hazards regression, and Kaplan-Meier survival analysis. RESULTS:Among 878 women (mean age, 49 ± 9 years), 234 were US-positive and 644 were US-negative; 283 patients were pathologic node-positive (pN ≥ 1) and 595 were node-negative (pN0). Preoperative axillary US demonstrated a sensitivity of 42.4% (95% confidence interval [CI], 36.8-48.2); specificity, 80.8% (95% CI, 77.5-83.8); positive predictive value, 51.3% (95% CI, 44.9-57.6); and negative predictive value, 74.7% (95% CI, 71.2-77.9). The US-positive group had a higher rate of axillary lymph node dissection (62.8% vs. 32.8%), greater mean number of metastatic nodes (2.6 vs. 0.5), and higher proportion of macrometastasis (94.2% vs. 71.8%) compared with the US-negative group (all p < 0.001). The 10-year recurrence-free survival was lowest in the pN-positive/US-positive group (90.3%; 95% CI, 82.7-94.7), intermediate in the pN-positive/US-negative group (92.4%; 95% CI, 86.7-95.7), and highest in the pN-negative group (97.4%; 95% CI, 95.4-98.5) (log-rank p < 0.001). CONCLUSION:Preoperative axillary US might help assess lymph node metastasis in clinically node-negative patients. Moreover, US positivity was associated with an increased risk of long-term recurrence.

PURPOSE:This study aims to investigate the clinical characteristics, outcomes, and predictors of brain metastases in human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer patients who achieved pathological complete response (pCR) following neoadjuvant chemotherapy (NAC). This research seeks to inform surveillance strategies and optimize management for high-risk subgroups. MATERIALS AND METHODS:A retrospective analysis of 1,757 patients (2008-2022) classified them into pCR (n=914) and non-pCR (n=843) groups post-NAC. Collected data included demographics, clinical features, and metastasis parameters. Survival outcomes and brain metastasis predictors were assessed using Kaplan-Meier curves, Cox models, and logistic regression. RESULTS:Among pCR patients, brain metastases accounted for 54.2% of distant metastases, significantly affecting overall survival (p < 0.001). Median distant metastasis-free survival was shorter for brain metastases (13.4 months) compared to extracranial metastases (31.1 months) in the pCR group (p=0.005). Positive supraclavicular node (SCN) fine needle aspiration (FNA) and clinical N3 (cN3) category were the strongest predictors of brain metastases (SCN FNA: odds ratio [OR], 12.9; p < 0.001; cN3: OR, 12.1; p < 0.001). Multivariable Cox regression analysis revealed that positive SCN FNA and cN3 category were strong predictors of reduced distant metastasis-free survival (SCN FNA: hazard ratio, 2.5; 95% confidence interval [CI], 1.3 to 3.6; p < 0.001; cN3: hazard ratio, 11.3; 95% CI, 4.9 to 33.0; p < 0.001). CONCLUSION:This study highlights the challenges of brain metastases in HER2-positive pCR patients, emphasizing the need for tailored therapeutic strategies and enhanced surveillance. High lymph node burden prior to NAC is a significant factor in risk assessment. Therefore, it may be advisable to recommend post-surgery surveillance for high-risk patients.

Objectives: This study aimed to compare ultrasound (US) findings between automated and handheld breast ultrasound (ABUS and HHUS, respectively) in small breast cancers, based on the breast imaging reporting and data system (BI-RADS) category. Methods: We included 51 women (mean age: 52 years; range: 39–66 years) with breast cancer (invasive or DCIS), all of whom underwent both ABUS and HHUS. Patients with tumors measuring ≤1 cm on either modality were enrolled. Two breast radiologists retrospectively evaluated multiple imaging features, including shape, orientation, margin, echo pattern, and posterior characteristics and assigned BI-RADS categories. Lesion sizes were compared between US and pathological findings. Statistical analyses were performed using Bowker’s test of symmetry, a paired t-test, and a cumulative link mixed model. Results: ABUS assigned lower BI-RADS categories than HHUS while still maintaining malignancy suspicion in categories 4A or higher (54.8% consistent with HHUS; 37.3% downcategorized in ABUS, p = 0.005). While ABUS demonstrated less aggressive margins in some cases (61.3% consistent with HHUS; 25.8% showing fewer suspicious margins in ABUS), this difference was not statistically significant (p = 0.221). Similarly, ABUS exhibited slightly greater height–width ratios compared to HHUS (median, interquartile range: 0.98, 0.7–1.12 vs. 0.86, 0.74–1.10, p = 0.166). No significant differences were observed in other US findings or tumor sizes between the two modalities (all p > 0.05). Conclusions: Small breast cancers exhibited suspicious US features on both ABUS and HHUS, yet they were assigned lower BI-RADS assessment categories on ABUS compared to HHUS. Therefore, when conducting breast cancer screening with ABUS, it is important to remain attentive to even subtle suspicious findings, and active consideration for biopsy may be warranted.

Abstract Background: Triple-negative breast cancer (TNBC) have had significantly worse survival outcome compared to other BC subtypes even though treatment strategies of TNBC have been advanced. The advent of immune checkpoint inhibitors (ICIs), especially pembrolizumab, a PD-1 inhibitor, has started to revolutionize TNBC treatment, showing encouraging effects in improving survival outcomes regardless of treatment settings. In neoadjuvant setting, pembrolizumab with cytotoxic chemotherapy achieved 13.6 % of pathologic complete response rate improvement and 36% of three-year event reduction. Therefore, pembrolizumab has highlighted new dimensions of TNBC's immunogenic characteristics. However, no immunogenic characteristics to predict the response of pembrolizumab have not been revealed. Methods: This study was designed as prospective, translational research for stage II or III TNBC patients scheduled for neoadjuvant chemotherapy with or without pembrolizumab followed by curative surgery. Tissue and blood samples were collected at baseline, 1 or 3 weeks after the first treatment initiation and curative surgery. We employed various single-cell and bulk RNA techniques for our multiomic analysis, including peripheral blood mononuclear cell (PBMC) single-cell RNA sequencing, T cell receptor sequencing (scTCR), high-resolution single-cell spatial transcriptomics (Xenium) targeting 380 genes, and bulk PBMC and tissue TCR analysis Results: From March 2023 to October 2023, 37 patients were enrolled in this study. Of 37 patients, we collected 36 blood and BC tissue samples at baseline, as well as 35 blood and 14 BC tissues at follow-up. These samples were analyzed and also compared with sex and age-matched healthy controls (n = 65). Of 37 patients, two patients were treated with only cytotoxic chemotherapy without pembrolizumab. We observed substantial increases in both systemic and localized immune responses, primarily marked by an upsurge in activated T cells and a decrease in regulatory T cells. A notable rise in TCR diversity post one week of treatment was followed by clonal expansion of activated T cells after three weeks in both blood and tissue. In addition, we observed a significant enrichment of pathways related to inflammatory response in classical monocytes following treatment. Conclusion: The findings from this study significantly enhance our understanding of the dynamics of circulating and local immune cells in TNBC, analyzed at a single-cell level with spatial information. These insights reveal how pembrolizumab alters the immune landscape and correlates these changes with treatment responses. Importantly, the data provide valuable indicators for predicting which TNBC patients are more likely to respond to neoadjuvant pembrolizumab therapy. Citation Format: Eun Seop Seo, Hae Hyun Jung, Kibyung Kim, Kyunghee Park, Eun Young Ko, Byung Joo Chae, Jeong Eon Lee, Eun Yoon Cho, Ji-Yeon Kim, Woong-Yang Park. Identification of circulating and spatial dynamics of immune cells response to to immune checkpoint inhibitors in triple-negative breast cancer at single-cell resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1176.

Identifying whether there is residual carcinoma in remaining suspicious calcifications after neoadjuvant chemotherapy (NAC) in breast cancer patients can provide crucial information for surgeons in determining the most appropriate surgical approach. Therefore, we investigated factors predicting calcifications without residual carcinoma (ypCalc_0) or with residual carcinoma (ypCalc_ca) and aimed to develop a prediction model for patients exhibiting residual suspicious calcifications on mammography but complete response on MRI after NAC. This retrospective study included breast cancer patients undergoing NAC, showing residual suspicious mammographic calcifications but complete response on MRI between January 2019 and December 2020 (development set) and between January 2021 and December 2022 (validation set). Multivariable logistic regression analysis identified significant factors associated with ypCalc_0. The prediction model, developed using a decision tree and factors from logistic regression analysis, was validated in the validation set. The development set included 134 women (mean age, 50.6 years; 91 with ypCalc_0 and 43 with ypCalc_ca) and validation set included 146 women (mean age, 51.0 years; 108 with ypCalc_0 and 38 with ypCalc_ca). Molecular subtype (P = .0002) and high Ki-67 (P = .02) emerged as significant independent factors associated with ypCalc_0 in the development set. The prediction model, incorporating hormone receptor (HR)−/human epidermal growth factor receptor 2 (HER2)+ with high Ki-67 as ypCalc_0 predictors, and HR+/HER2− cancers or HR+/HER2+ or triple-negative (TN) cancers with low Ki-67, as ypCalc_ca predictors, achieved an area under receiver operating characteristic curve of 0.844 (95

Background:Despite the common use of ultrasound (US)-guided fine-needle aspiration (FNA) for axillary node (AN) in breast cancer patients, only a limited number of studies are available regarding the diagnostic performance of AN-FNA according to the suspicion level based on US findings. This study compares the outcomes of US-guided AN-FNA in breast cancer patients, differentiating between those undergoing staging and surveillance.Methods:A cross-sectional retrospective study with retrospective analysis was conducted on 767 consecutive AN-FNA procedures performed in 2017 at Samsung Medical Center in Seoul, with 654 for staging and 113 for surveillance in breast cancer patients. The radiologists performed axillary US and the specific finding was prospectively classified into the AN-reporting and data system (AN-RADS) category 3-5 before FNA. The malignancy rate of each category was evaluated. The chi-square test, with or without Bonferroni correction, or Fisher's exact test was used to compare the malignancy rates between the staging and surveillance groups for each category.Results:Among the 767 AN-FNAs, 424 (55.3%) were malignant. The malignancy rate was significantly higher in the staging group (59.5%) than in the surveillance group (31.0%, P<0.0001). The distribution of AN-RADS categories differed between the groups (P=0.015), with 4A being the most common. The malignancy rates in categories 3, 4A, 4B, 4C, and 5 were as follows: 5.6%, 36.0%, 77.4%, 87.7%, and 98.4% in the staging group, and 0.0%, 9.7%, 53.3%, 88.9%, and 100% in the surveillance group. The malignancy rate was significantly different between the two groups only in category 4A (P=0.0001).Conclusions:AN-FNA according to AN-RADS category appears to be an appropriate method for determination of axillary nodal status. Overall malignancy rate of AN-FNA in breast cancer patients was higher in the staging group than in the surveillance group. According to the suspicion level, the difference between two groups was significant only in category 4A.

RATIONALE AND OBJECTIVES:This study aimed to identify the factors associated with malignant biopsy results for new lesions within one year after breast cancer surgery. MATERIALS AND METHODS:This retrospective study included 192 lesions from 186 patients who underwent biopsy for newly developed breast lesions within one year of breast cancer surgery. All patients underwent breast ultrasound (US) at 6 months and breast US with mammography one year after surgery. We analyzed the biopsy results, patient age, characteristics of previous cancers (histologic type, stage, molecular subtype, histologic and nuclear grade, Ki-67 index, extensive intraductal component, lymphovascular invasion (LVI)), history of neoadjuvant chemotherapy (NAC), adjuvant therapy, and characteristics of biopsied lesions (location, mode of detection, imaging features, and Breast Imaging Reporting and Data System category). Multivariate logistic regression was performed to predict malignant results after a biopsy of the new lesion in the early postoperative period. RESULTS:The mean patient age was 49.0 (range, 28-82) years. During follow-up, 137 lesions developed in the ipsilateral remnant breast or mastectomy bed, and 55 lesions developed in the contralateral breast. In total, 37 (19.3%) of the biopsied lesions were malignant, and the following conditions were associated with malignant results in the newly detected lesions: irregularly shaped hypoechoic mass with increased vascularity, presence of previous LVI, history of NAC, and no history of adjuvant radiotherapy or hormone therapy in the indicated patients. CONCLUSION:Active biopsy may be warranted for new lesions with suspicious imaging findings in the breast or operation bed of patients with LVI, a history of NAC, and no history of adjuvant radiotherapy or hormone therapy, even within one year of breast cancer surgery.