Breast cryoablation for the palliative treatment of indolent subtype of multicentric triple-negative breast cancer.

Breast cryoablation for palliative and curative treatment of breast cancer has been performed for decades. Although there is a recent resurgence of interest in breast cryoablation with curative intent for unifocal, hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, this report highlights the essential role that cryoablation can play in the palliative treatment of multicentric oestrogen and progesterone receptor-negative and human epidermal growth factor receptor 2-negative (triple-negative) breast cancer, meeting the select pretreatment objectives such as breast or nipple pain relief and prevention of tumour erosion through the skin or nipple in patients who have failed or cannot tolerate the standard of care treatment.

Longitudinal dynamic contrast-enhanced MRI radiomic models for early prediction of response to neoadjuvant systemic therapy in triple-negative breast cancer.

Early prediction of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) patients could help oncologists select individualized treatment and avoid toxic effects associated with ineffective therapy in patients unlikely to achieve pathologic complete response (pCR). The objective of this study is to evaluate the performance of radiomic features of the peritumoral and tumoral regions from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) acquired at different time points of NAST for early treatment response prediction in TNBC. This study included 163 Stage I-III patients with TNBC undergoing NAST as part of a prospective clinical trial (NCT02276443). Peritumoral and tumoral regions of interest were segmented on DCE images at baseline (BL) and after two (C2) and four (C4) cycles of NAST. Ten first-order (FO) radiomic features and 300 gray-level-co-occurrence matrix (GLCM) features were calculated. Area under the receiver operating characteristic curve (AUC) and Wilcoxon rank sum test were used to determine the most predictive features. Multivariate logistic regression models were used for performance assessment. Pearson correlation was used to assess intrareader and interreader variability. Seventy-eight patients (48%) had pCR (52 training, 26 testing), and 85 (52%) had non-pCR (57 training, 28 testing). Forty-six radiomic features had AUC at least 0.70, and 13 multivariate models had AUC at least 0.75 for training and testing sets. The Pearson correlation showed significant correlation between readers. In conclusion, Radiomic features from DCE-MRI are useful for differentiating pCR and non-pCR. Similarly, predictive radiomic models based on these features can improve early noninvasive treatment response prediction in TNBC patients undergoing NAST.

Deep Learning for Fully Automatic Tumor Segmentation on Serially Acquired Dynamic Contrast-Enhanced MRI Images of Triple-Negative Breast Cancer.

Accurate tumor segmentation is required for quantitative image analyses, which are increasingly used for evaluation of tumors. We developed a fully automated and high-performance segmentation model of triple-negative breast cancer using a self-configurable deep learning framework and a large set of dynamic contrast-enhanced MRI images acquired serially over the patients' treatment course. Among all models, the top-performing one that was trained with the images across different time points of a treatment course yielded a Dice similarity coefficient of 93% and a sensitivity of 96% on baseline images. The top-performing model also produced accurate tumor size measurements, which is valuable for practical clinical applications.

Breast Cancer Cryoablation Fundamentals Past and Present: Technique Optimization and Imaging Pearls.

Surgical treatment for breast cancer has evolved from radical mastectomy to modified radical mastectomy to breast-conserving surgery. As the de-escalation of surgical treatment for breast cancer continues, nonsurgical treatment for early-stage breast cancer with favorable ancillary features (low grade, positivity for hormone receptors) is being explored. Of the nonsurgical treatment options, cryoablation has demonstrated the greatest appeal, proven to be effective, safe, well tolerated, and feasible in an outpatient setting with local anesthetic alone. Results of past and interim results of current trials of cryoablation of stage I low-grade breast cancer with curative intent are promising, with an overall clinical success rate of 98% and recurrence rates consistent with those expected following lumpectomy. Cryoablation is also an alternative palliative treatment for patients who cannot tolerate or who have disease that is refractory to or recurs after standard-of-care breast cancer treatment and may have immunological therapeutic effects, warranting future research. Understanding the indications and optimal technique for breast cancer cryoablation and understanding typical imaging findings after cryoablation are essential to ensure the success of the procedure in carefully selected patients.

Assessment of Response to Neoadjuvant Systemic Treatment in Triple-Negative Breast Cancer Using Functional Tumor Volumes from Longitudinal Dynamic Contrast-Enhanced MRI.

Early assessment of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) is critical for patient care in order to avoid the unnecessary toxicity of an ineffective treatment. We assessed functional tumor volumes (FTVs) from dynamic contrast-enhanced (DCE) MRI after 2 cycles (C2) and 4 cycles (C4) of NAST as predictors of response in TNBC. A group of 100 patients with stage I-III TNBC who underwent DCE MRI at baseline, C2, and C4 were included in this study. Tumors were segmented on DCE images of 1 min and 2.5 min post-injection. FTVs were measured using the optimized percentage enhancement (PE) and signal enhancement ratio (SER) thresholds. The Mann-Whitney test was used to compare the performance of the FTVs at C2 and C4. Of the 100 patients, 49 (49%) had a pathologic complete response (pCR) and 51 (51%) had a non-pCR. The maximum area under the receiving operating characteristic curve (AUC) for predicting the treatment response was 0.84 (p < 0.001) for FTV at C4 followed by FTV at C2 (AUC = 0.82, p < 0.001). The FTV measured at baseline was not able to discriminate pCR from non-pCR. FTVs measured on DCE MRI at C2, as well as at C4, of NAST can potentially predict pCR and non-pCR in TNBC patients.

Predictors of success in establishing orthotopic patient-derived xenograft models of triple negative breast cancer.

Patient-derived xenograft (PDX) models of breast cancer are an effective discovery platform and tool for preclinical pharmacologic testing and biomarker identification. We established orthotopic PDX models of triple negative breast cancer (TNBC) from the primary breast tumors of patients prior to and following neoadjuvant chemotherapy (NACT) while they were enrolled in the ARTEMIS trial (NCT02276443). Serial biopsies were obtained from patients prior to treatment (pre-NACT), from poorly responsive disease after four cycles of Adriamycin and cyclophosphamide (AC, mid-NACT), and in cases of AC-resistance, after a 3-month course of different experimental therapies and/or additional chemotherapy (post-NACT). Our study cohort includes a total of 269 fine needle aspirates (FNAs) from 217 women, generating a total of 62 PDX models (overall success-rate = 23%). Success of PDX engraftment was generally higher from those cancers that proved to be treatment-resistant, whether poorly responsive to AC as determined by ultrasound measurements mid-NACT (p = 0.063), RCB II/III status after NACT (p = 0.046), or metastatic relapse within 2 years of surgery (p = 0.008). TNBC molecular subtype determined from gene expression microarrays of pre-NACT tumors revealed no significant association with PDX engraftment rate (p = 0.877). Finally, we developed a statistical model predictive of PDX engraftment using percent Ki67 positive cells in the patient's diagnostic biopsy, positive lymph node status at diagnosis, and low volumetric reduction of the patient's tumor following AC treatment. This novel bank of 62 PDX models of TNBC provides a valuable resource for biomarker discovery and preclinical therapeutic trials aimed at improving neoadjuvant response rates for patients with TNBC.

Mid-treatment Ultrasound Descriptors as Qualitative Imaging Biomarkers of Pathologic Complete Response in Patients with Triple-Negative Breast Cancer.

This study aimed to investigate mid-treatment breast tumor ultrasound characteristics that may predict eventual pathologic complete response (pCR) in triple-negative breast cancer; specifically, we examined associations between pCR and two parameters: tumor response pattern and tumor appearance. Ultrasound was performed at mid-treatment, defined as the completion of four cycles of anthracycline-based chemotherapy and before receiving taxane-based chemotherapy. Consensus imaging review was performed while blinded to pathology results (i.e., pCR/non-pCR) from surgery. Tumor response pattern was described as "complete," "concentric," "fragmented," "stable" or "progression." Tumor appearance was designated as "mass," "architectural distortion," "flat tumor bed" or "clip only." Univariate and multivariate regression analyses of 144 participants showed significant associations between mid-treatment response pattern and pCR (p = 0.0348 and p = 0.0173, respectively), with complete and concentric response patterns more likely to achieve pCR than other patterns. Univariate and multivariate regression analyses further showed significant associations between mid-treatment tumor appearance and pCR (p < 0.0001 for both), with persistent appearance of mass less likely than other appearances to achieve pCR. To conclude, our study demonstrated strong associations between pCR and both tumor response pattern and tumor appearance, thereby suggesting that these parameters have potential as qualitative imaging biomarkers of pCR in triple-negative breast cancer.

COVID-19 Vaccine-Related Axillary and Cervical Lymphadenopathy in Patients with Current or Prior Breast Cancer and Other Malignancies: Cross-Sectional Imaging Findings on MRI, CT, and PET-CT.

Breast radiologists are increasingly seeing patients with axillary adenopathy related to COVID-19 vaccination. Vaccination can cause levels I-III axillary as well as cervical lymphadenopathy. Appropriate management of vaccine-related adenopathy may vary depending on clinical context. In patients with current or past history of malignancy, vaccine-related adenopathy can be indistinguishable from nodal metastasis. This article presents imaging findings of oncology patients with adenopathy seen in the axilla or neck on cross-sectional imaging (breast MRI, CT, or PET-CT) after COVID-19 vaccination. Management approach and rationale is discussed, along with consideration on strategies to minimize false positives in vaccinated cancer patients. Time interval between vaccination and adenopathy seen on breast MRI, CT, or PET-CT is also reported.

Functional Tumor Volume by Fast Dynamic Contrast-Enhanced MRI for Predicting Neoadjuvant Systemic Therapy Response in Triple-Negative Breast Cancer.

BACKGROUND: Dynamic contrast-enhanced (DCE) MRI is useful for diagnosis and assessment of treatment response in breast cancer. Fast DCE MRI offers a higher sampling rate of contrast enhancement curves in comparison to conventional DCE MRI, potentially characterizing tumor perfusion kinetics more accurately for measurement of functional tumor volume (FTV) as a predictor of treatment response. PURPOSE: To investigate FTV by fast DCE MRI as a predictor of neoadjuvant systemic therapy (NAST) response in triple-negative breast cancer (TNBC). STUDY TYPE: Prospective. POPULATION/SUBJECTS: Sixty patients with biopsy-confirmed TNBC between December 2016 and September 2020. FIELD STRENGTH/SEQUENCE: A 3.0 T/3D fast spoiled gradient echo-based DCE MRI ASSESSMENT: Patients underwent MRI at baseline and after four cycles (C4) of NAST, followed by definitive surgery. DCE subtraction images were analyzed in consensus by two breast radiologists with 5 (A.H.A.) and 2 (H.S.M.) years of experience. Tumor volumes (TV) were measured on early and late subtractions. Tumors were segmented on 1 and 2.5-minute early phases subtractions and FTV was determined using optimized signal enhancement thresholds. Interpolated enhancement curves from segmented voxels were used to determine optimal early phase timing. STATISTICAL TESTS: Tumor volumes were compared between patients who had a pathologic complete response (pCR) and those who did not using the area under the receiver operating curve (AUC) and Mann-Whitney U test. RESULTS: About 26 of 60 patients (43%) had pCR. FTV at 1 minute after injection at C4 provided the best discrimination between pCR and non-pCR, with AUC (95% confidence interval [CI]) = 0.85 (0.74,0.95) (P < 0.05). The 1-minute timing was optimal for FTV measurements at C4 and for the change between C4 and baseline. TV from the early phase at C4 also yielded a good AUC (95%CI) of 0.82 (0.71,0.93) (P < 0.05). DATA CONCLUSION: FTV and TV measured at 1 minute after injection can predict response to NAST in TNBC. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: 4.

Prospective Registry Trial Assessing the Use of Magnetic Seeds to Locate Clipped Nodes After Neoadjuvant Chemotherapy for Breast Cancer Patients.

BACKGROUND: Targeted axillary dissection (TAD) involves locating and removing both clipped nodes and sentinel nodes for assessment of the axillary response to neoadjuvant chemotherapy (NAC) by clinically node-positive breast cancer patients. Initial reports described radioactive seeds used for localization, which makes the technique difficult to implement in some settings. This trial was performed to determine whether magnetic seeds can be used to locate clipped axillary lymph nodes for removal. METHODS: This prospective registry trial enrolled patients who had biopsy-proven node-positive disease with a clip placed in the node and treatment with NAC. A magnetic seed was placed under ultrasound guidance in the clipped node after NAC. All the patients underwent TAD. RESULTS: Magnetic seeds were placed in 50 patients by 17 breast radiologists. All the patients had successful seed placement at the first attempt (mean time for localization was 6.1 min; range 1-30 min). The final position of the magnetic seed was within the node (n = 44, 88%), in the cortex (n = 3, 6%), less than 3 mm from the node (n = 2, 4%), or by the clip when the node could not be adequately visualized (n = 1, 2%). The magnetic seed was retrieved at surgery from all the patients. In 49 (98%) of the 50 cases, the clip and magnetic seed were retrieved from the same node. Surgeons rated the transcutaneous and intraoperative localization as easy for 43 (86%) of the 50 cases. No device-related adverse events occurred. CONCLUSIONS: Localization and selective removal of clipped nodes can be accomplished safely and effectively using magnetic seeds.

Tumor necrosis by pretreatment breast MRI: association with neoadjuvant systemic therapy (NAST) response in triple-negative breast cancer (TNBC).

PURPOSE: To determine if tumor necrosis by pretreatment breast MRI and its quantitative imaging characteristics are associated with response to NAST in TNBC. METHODS: This retrospective study included 85 TNBC patients (mean age 51.8 ± 13 years) with MRI before NAST and definitive surgery during 2010-2018. Each MRI included T2-weighted, diffusion-weighted (DWI), and dynamic contrast-enhanced (DCE) imaging. For each index carcinoma, total tumor volume including necrosis (TTV), excluding necrosis (TV), and the necrosis-only volume (NV) were segmented on early-phase DCE subtractions and DWI images. NV and %NV were calculated. Percent enhancement on early and late phases of DCE and apparent diffusion coefficient were extracted from TTV, TV, and NV. Association between necrosis with pathological complete response (pCR) was assessed using odds ratio (OR). Multivariable analysis was used to evaluate the prognostic value of necrosis with T stage and nodal status at staging. Mann-Whitney U tests and area under the curve (AUC) were used to assess performance of imaging metrics for discriminating pCR vs non-pCR. RESULTS: Of 39 patients (46%) with necrosis, 17 had pCR and 22 did not. Necrosis was not associated with pCR (OR, 0.995; 95% confidence interval [CI] 0.4-2.3) and was not an independent prognostic factor when combined with T stage and nodal status at staging (P = 0.46). None of the imaging metrics differed significantly between pCR and non-pCR in patients with necrosis (AUC < 0.6 and P > 0.40). CONCLUSION: No significant association was found between necrosis by pretreatment MRI or the quantitative imaging characteristics of tumor necrosis and response to NAST in TNBC.

Breast Imaging After Dark.

Patients may present to the emergency department with breast complaints due to traumatic or nontraumatic changes in the breast. Benign and malignant breast pathologies may mimic each other both in clinical presentation and imaging appearance. A complex cystic and solid mass seen on ultrasound in a patient with a palpable mass can represent breast cancer, abscess, or hematoma. A unilateral swollen breast may result from inflammatory breast cancer, mastitis, or other benign etiologies; correlation with clinical history, physical exam, and close follow-up are required to ensure complete resolution of symptoms. Uncommon breast entities such as granulomatous mastitis and breast implant-associated anaplastic large-cell lymphoma may cause changes in the appearance of the breast that prompt a patient to seek initial evaluation in the emergency department. Imaging evaluation of the breast in the emergency department is limited, and it is important that patients with a breast complaint be referred to a dedicated breast center for complete evaluation at an appropriate time interval after their discharge from the emergency department.

Male Mammary Paget Disease: A Tale of 2 Contrasting Cases.

Mammary Paget disease (MPD) comprises 1.45% all male breast cancers, compared with only 0.68% of all female breast cancers. Patients usually present in the fifth and sixth decades of life with ulceration, eczematous changes, discharge, bleeding, itching, and induration of the nipple and areola. Typically, there is a delay in definitive diagnosis and treatment from the onset of symptoms because most patients are initially treated for a rash. At the time of diagnosis, about half of the patients may have palpable breast mass, positive lymph nodes, or both. In this article, we present 2 cases of male MPD representing the extremes of clinical, radiologic, and histopathologic spectrum of the disease. One patient presented with a rash of the nipple of several months duration without an underlying lesion, whereas the other presented with sensitivity and pain of the nipple for 1 year and an underlying mass. Biopsies were diagnostic of MPD in both cases, and definitive surgery revealed an underlying ductal carcinoma in situ in the first case and an invasive ductal carcinoma in the second, highlighting the importance of early biopsy to initiate appropriate management.

Axillary ultrasound during neoadjuvant systemic therapy in triple-negative breast cancer patients.

PURPOSE: To investigate the value of performing mid-treatment axillary ultrasound (AUS) in triple-negative breast cancer (TNBC) patients who are undergoing neoadjuvant systemic therapy (NAST) by determining the optimal cutoff number of abnormal nodes associated with residual nodal disease on surgical pathology. MATERIALS AND METHODS: This sub-study, an interim analysis of an ongoing single-institution clinical trial enrolling patients with stage I-III TNBC, included 106 patients. Number of abnormal nodes at mid-treatment was assessed and recorded by experienced breast radiologists, who empirically categorized lymph nodes using a binary approach of sonographically-normal versus abnormal. Pathologic lymph node positivity was defined as presence of macrometastasis or micrometastasis in ≥1 axillary node from sentinel lymph node biopsy and/or axillary lymph node dissection. RESULTS: Of 106 patients, 26 (25 %) had residual nodal disease and 80 (75 %) had no nodal disease at surgery. Median number of abnormal nodes at mid-treatment was 5 (standard deviation [SD], 5) for patients with residual nodal disease and 0 (SD, 2) for patients with no nodal disease at surgery (p < 0.0001). TNBC patients with >4 abnormal nodes at mid-treatment had a significantly higher chance of being node-positive at surgery (AUC = 0.908, p < 0.0001; PPV = 90 %). CONCLUSION: Our data suggest that a cutoff of >4 abnormal nodes on mid-treatment AUS is associated with residual disease post-NAST. If our findings are substantiated by subsequent analyses, then mid-treatment AUS could be used to identify patients unlikely to achieve nodal pathologic complete response and who should be offered alternative therapy.

Imaging features of triple-negative breast cancers according to androgen receptor status.

OBJECTIVE: Different molecular subtypes of triple-negative breast cancer (TNBC) have previously been identified through analysis of gene expression profiles. The luminal androgen receptor (LAR) subtype has been shown to have a lower rate of pathologic complete response to neoadjuvant chemotherapy than other TNBC subtypes. The purpose of this study was to determine if the imaging features of TNBCs differ by AR (androgen receptor) status, which is a surrogate immunohistochemical (IHC) marker for the chemoresistant LAR subtype of TNBC. MATERIALS AND METHODS: This sub-study was part of a clinical trial in patients with stage I-III TNBC who were prospectively monitored for response while receiving neoadjuvant systemic therapy (NAST) at a single comprehensive cancer center. This interim imaging analysis included 144 patients with known AR status measured by IHC. AR-positive (AR+) tumors were defined as those in which at least 10% of tumor cells had positive nuclear AR staining. Two experienced, fellowship-trained breast radiologists who were blinded to the IHC results retrospectively reviewed and reached consensus on all imaging studies for the index lesion (i.e., mammogram, ultrasound, and breast magnetic resonance imaging). The index lesion for each patient was reviewed and described according to the fifth edition of the Breast Imaging Reporting and Data System lexicon. Logistic regression modeling was used to identify imaging features predictive of AR status. p ≤ 0.05 was considered statistically significant. RESULTS: Univariate logistic regression models for AR status showed that AR+ TNBC was significantly associated with heterogeneously dense breast composition on mammography (p = 0.02), mass with calcifications (p = 0.05), irregular mass shape on mammography (p = 0.03), and irregular mass shape on sonography (p = 0.003). Multivariate logistic regression models for AR status showed that AR+ TNBC was significantly associated with heterogeneously dense breast composition on mammography (p = 0.01), high mass density on mammography (p = 0.003), and irregular mass shape on sonography (p = 0.0004). CONCLUSION: The imaging features of TNBCs differ by AR status. Multimodality breast imaging may help identify the LAR subtype of TNBC, which has been shown to be a subtype that is relatively resistant to neoadjuvant chemotherapy.

Finding Inspiration for the Next Generation of Breast Radiologists.

Challenges currently facing breast radiologists, including controversial screening mammography guidelines, radiologist burnout, and the perceived threat posed by artificial intelligence could deter potential candidates from pursuing a career in radiology. However, breast radiologists play a fulfilling role by decreasing the effect of breast cancer through both early detection and direct interaction with patients and interdisciplinary clinical colleagues. While perception is that artificial intelligence will threaten the need for radiologists, it is more likely that it will improve image interpretation and efficiency in workflow, thereby further improving patient care. Trainees can be engaged in breast imaging through interactive teaching methods and by role modeling clinical and image interpretation skills.

Effect of Mammography on Marker Clip Migration After Stereotactic-Guided Core Needle Breast Biopsy.

OBJECTIVE: To determine whether the type of projection used-same as or orthogonal to the projection used during a stereotactic-guided core needle biopsy procedure-to obtain the first view on a 2-view postbiopsy mammogram affects biopsy marker clip migration. PATIENTS AND METHODS: We prospectively recruited women scheduled to undergo stereotactic-guided core needle breast biopsy with marker clip deployment and categorized the women randomly into one of the following 2 groups: first view on the postbiopsy mammogram obtained in the same projection as that used during the biopsy procedure (group 1), or first view on the postbiopsy mammogram obtained orthogonally to the projection used during the biopsy procedure (group 2). Masks of the prebiopsy and postbiopsy mammograms were used to determine whether and how far the biopsy marker clip moved from the biopsy cavity. RESULTS: Sixty-two biopsies were performed in 60 patients (mean age = 56 years; range: 30-78 years); 30 women (32 lesions) were randomized to group 1 and 30 women (30 lesions) were randomized to group 2. Marker clip migration occurred in 10 cases in group 1 (20%, <1cm; 30%, 1-3cm; and 60%, >3cm) and 8 cases in group 2 (0%, <1cm; 75%, 1-3cm; and 25%, >3cm). The mean displacement distance was 0.84cm in group 1 and 0.67cm in group 2 (P = 0.83). The mean displacement distance difference was -0.17cm with a 95% bootstrap confidence interval from -0.87 to 0.57cm. CONCLUSION: The type of projection used to obtain the first view on the postbiopsy mammogram, relative to that used during the stereotactic biopsy procedure, did not affect biopsy marker clip migration.

Histopathologic correlation of residual mammographic microcalcifications after neoadjuvant chemotherapy for locally advanced breast cancer.

OBJECTIVE: This study was designed to determine the histopathologic correlation at surgery of residual mammographic calcifications in patients after neoadjuvant chemotherapy (NAC) for locally advanced breast cancer (LABC). METHODS: This single-institution, retrospective study was approved by the Institutional Review Board and was Health Insurance Portability and Accountability act compliant. Women with LABC who underwent NAC between January 1, 2004 and December 31, 2008 and had mammography performed before and after NAC available for review were included in this study. The extent of microcalcifications associated with cancer before and after the completion of NAC was correlated with histopathology and biomarker status. RESULTS: Of 494 patients who met the inclusion criteria, 106 demonstrated microcalcifications on pre-, post-chemotherapy, or both sets of mammograms and were included in this study. Of 106 women, 31 (29 %) had invasive ductal carcinoma (IDC) and 60 (57 %) had both IDC and ductal carcinoma in situ (DCIS). Microcalcifications decreased or remained stable in 76 (72 %) patients after completion of NAC. Correlation of microcalcifications with histopathology after NAC showed that 43 (40.6 %) patients had tumors associated with benign pathology. Of 32 patients with pathologic complete response, calcifications were associated with DCIS in 9 (9 %) and benign findings in 21 (22 %). The proportion of residual malignant calcifications was higher in ER+ versus ER- patients after NAC. CONCLUSIONS: The extent of calcifications on mammography following NAC does not correlate with the extent of residual disease in up to 22 % of women; this information may impact surgical planning in subsets of women with breast cancer.

Role of sonography for the locoregional staging of breast cancer.

OBJECTIVE: This article describes the use of sonography for the locoregional staging of breast cancer. Sonography may identify mammographically occult disease within the breast. Sonography of the regional nodal basins, including the axilla, infraclavicular, supraclavicular, and internal mammary regions, can identify nodal metastases, which may upstage disease and have implications for prognosis. CONCLUSION: The anatomy of the regional nodal basins and the TNM staging system for breast cancer are reviewed, and the implications of ultrasound-detected disease on clinical management and treatment decisions are discussed.