A comparison of the diagnostic accuracy of magnetic resonance imaging to axillary ultrasound in the detection of axillary nodal metastases in newly diagnosed breast cancer

The Role of MRI in Breast Cancer and Breast Conservation Therapy

Contrast-enhanced breast MRI has an established role in aiding in the detection, evaluation, and management of breast cancer. This article discusses MRI sequences, the clinical utility of MRI, and how MRI has been evaluated for use in breast radiotherapy treatment planning. We highlight the contribution of MRI in the decision-making regarding selecting appropriate candidates for breast conservation therapy and review the emerging role of MRI-guided breast radiotherapy.

Can Axillary Ultrasound Identify Node Positive Patients Who can Avoid an Axillary Dissection After Neoadjuvant Chemotherapy?

INTRODUCTION

Axillary lymph node dissection (ALND) is recommended for patients with invasive breast cancer with axillary metastasis treated with neoadjuvant chemotherapy (NAC) who do not have a nodal pathologic complete response (n-pCR). We hypothesized that patients with a single, ultrasound-suspicious, nonpalpable lymph node (LN) at diagnosis, who do not achieve an n-pCR, will have ypN1 disease on surgical pathology.

METHODS

This retrospective study identified breast cancer patients in our institution from 2012 to 2020 with axillary metastasis treated with NAC who did not achieve an n-pCR and had an ALND. Patient's tumor characteristics, axillary ultrasound, and lymph node disease burden at the time of surgery were reviewed.

RESULTS

Fifty five patients met the criteria and 36% had one suspicious LN on ultrasound, 25% had 2, and 38% had >3. After chemotherapy, 64% had ypN1 disease, 29% had ypN2 disease, and 7% had ypN3 disease. Of the 20 patients with one abnormal LN on initial ultrasound, 17 (85%, 95% CI 61-96%) had ypN1 disease. Eleven patients with one abnormal LN on initial ultrasound also had no suspicious LNs on prechemotherapy physical exam; among these patients, 100% had ypN1 disease.

CONCLUSIONS

For breast cancer patients who do not achieve an n-pCR after NAC, pretreatment normal clinical axillary exam and prechemotherapy ultrasound showing only one abnormal LN is associated with ypN1 disease. It may be reasonable to consider omitting completion ALND in this subset of patients while awaiting the results of the Alliance A011202 trial.

Extra-axillary nodal metastases in breast cancer: comparison of ultrasound, MRI, PET/CT, and CT

PURPOSE

To evaluate how ultrasound (US), MRI, PET/CT, and CT predict extra-axillary nodal metastases.

SUBJECTS AND METHODS

This IRB approved, retrospective study consisted of 124 suspicious supraclavicular and 88 internal mammary (IM) nodal cases with US and at least one additional cross-sectional examination (MRI, PET/CT or CT) from a total of 1472 invasive cancers with staging nodal US between January 2016-January 2019. Imaging findings were compared with the true node status, determined by fine needle aspirate (FNA) biopsy or evidence of response to chemotherapy on follow up imaging.

RESULTS

In the supraclavicular region, US had accuracy 98.2%, consisting of 97 true positives (TP), 27 false positives (FP), and 1348 true negative (TN). 93.5% of suspicious supraclavicular nodes had FNA for a PPV 78.2%. PET/CT had accuracy 88.6% (26 TP, 5 TN and 4 false negatives (FN)). CT exams had accuracy 61.7% (42 TP, 16 TN, 7 FP, and 29 FN). In the IM region, US had accuracy 93.2% (82 TP, 1 FP, 5 FN, and 1384 TN) but only 43.2% of suspicious IM nodes had FNA for a PPV 98.8%. MRI had accuracy 100.0% (all 47 TP). PET/CT exams had accuracy 96.8% (30 TP and 1FN). CT exams had accuracy 62.7% (36 TP, 1 TN, and 22 FN).

CONCLUSION

US/FNA has accuracy 98.2% and 93.2% in the supraclavicular and IM regions, however only 43.2% of suspicious IM nodes are directly sampled. In these cases, MRI or PET/CT can be used to problem solve and guide treatment decisions.

Distance Between the Tumour and Nipple as a Predictor of Axillary Lymph Node Involvement in Breast Cancer

Purpose

The possibility of axillary node metastasis via the lymphatics might be related to a cancer’s location within the breast. Previous studies of this topic had small sample sizes, inaccuracies because of subjective differences, and the inability to depict the entire three-dimensional structure of the breast. Here, we aimed to improve upon these existing drawbacks by retrospectively analysing whether tumour location (quadrants) and tumour–nipple distance can predict axillary node positivity.

Patients and Methods

We identified 961 patients with invasive breast cancer between January 2000 and April 2016. The tumour–nipple distance was objectively measured intraoperatively and clinicopathological information was extracted from hospital database. The distance was measured radially from the nipple to the epicentre rather than the edge of tumour to obviate confounders resulting from tumour size variations.

Results

A total of 847 breast cancers (839 patients) met the eligibility criteria and were included in the statistical analysis. The tumour–nipple distance was smaller in node-positive patients (n = 307; 2.76 ± 2.07 cm) than in node-negative patients (n = 297; 3.41 ± 2.18 cm) (p < 0.001). Tumour–nipple distance was an independent predictor of axillary involvement on logistic regression analysis. However, no statistically significant relationship was detected between node positivity and breast quadrant tumour location.

Conclusion

Tumour–nipple distance can be used to predict axillary lymph node metastasis and assist in surgical decision-making and therapy planning. However, exploratory studies are required to increase our understanding of the mechanism.

Textural Characteristics of Biopsy-proven Metastatic Axillary Nodes on Preoperative Breast MRI in Breast Cancer Patients: A Feasibility Study

OBJECTIVE

To determine the diagnostic accuracy of MRI textural analysis (TA) to differentiate malignant from benign axillary lymph nodes in patients with breast cancer.

METHODS

This was an institutional review board-approved retrospective study of axillary lymph nodes in women with breast cancer that underwent ultrasound-guided biopsy and contrast-enhanced (CE) breast MRI from January 2015 to December 2018. TA of axillary lymph nodes was performed on 3D dynamic CE T1-weighted fat-suppressed, 3D delayed CE T1-weighted fat-suppressed, and T2-weighted fat-suppressed MRI sequences. Quantitative parameters used to measure TA were compared with pathologic diagnoses. Areas under the curve (AUC) were calculated using receiver operating characteristic curve analysis to distinguish between malignant and benign lymph nodes.

RESULTS

Twenty-three biopsy-proven malignant lymph nodes and 24 benign lymph nodes were analyzed. The delayed CE T1-weighted fat-suppressed sequence had the greatest ability to differentiate malignant from benign outcome at all spatial scaling factors, with the highest AUC (0.84-0.93), sensitivity (0.78 [18/23] to 0.87 [20/23]), and specificity (0.76 [18/24] to 0.88 [21/24]). Kurtosis on the 3D delayed CE T1-weighted fat-suppressed sequence was the most prominent TA parameter differentiating malignant from benign lymph nodes (P < 0.0001).

CONCLUSION

This study suggests that MRI TA could be helpful in distinguishing malignant from benign axillary lymph nodes. Kurtosis has the greatest potential on 3D delayed CE T1-weighted fat-suppressed sequences to distinguish malignant and benign lymph nodes.

Value of Axillary Ultrasound after Negative Axillary MRI for Evaluating Nodal Status in High-Risk Breast Cancer

BACKGROUND

It is assumed that axillary ultrasound (AxUS) is the best method for axillary nodal evaluation in newly diagnosed breast cancer patients. However, few have evaluated the efficacy of preoperative axillary MRI. We compared the statistical accuracy of AxUS and MRI in detecting nodal metastases among breast cancer patients who were selected for neoadjuvant chemotherapy.

STUDY DESIGN

We retrospectively analyzed 219 breast cancer patients undergoing neoadjuvant chemotherapy from 2007 to 2015, all of whom had AxUS and breast MRI before chemotherapy. Two breast radiologists, blinded to clinical, pathologic, and AxUS findings, re-reviewed all breast MRIs, specifically focusing on axillary nodal characteristics. We correlated clinico-pathologic characteristics, AxUS, and MRI findings, and quantified predictive values of both imaging modalities.

RESULTS

Overall, 101 of 219 (47%) patients had T2 tumors. The most common abnormal nodal finding was size >10 mm. Axillary ultrasound and MRI agreed on nodal status in 192 of 219 patients (87.6%). When correlated with pre-chemotherapy needle biopsy in 129 patients, AxUS and axillary MRI performed similarly (sensitivity of 99.1% vs 97.4% and specificity 15.4% vs 15.4%, respectively). Only 4 of 129 (3.1%) patients had a negative MRI and positive AxUS; 3 of 4 of these patients (75%) had a positive biopsy and 2 of 3 had positive lymph nodes on final pathology, therefore suggesting MRI missed clinically significant disease in only 2 of 129 (1.5%) patients.

CONCLUSIONS

In a high-risk patient population, AxUS and MRI have similar statistical profiles in evaluating axillary nodal status. Routine use of AxUS after a normal axillary MRI is not warranted.

L’exploration axillaire : un standard du bilan préthérapeutique

L’exploration préthérapeutique axillaire est une étape majeure du bilan initial du cancer du sein. L’échographie associée à un prélèvement est actuellement recommandée en première intention. L’IRM et la TEP/TDM au 18FDG sont utiles dans l’évaluation ganglionnaire axillaire. Les sensibilités et spécificités des examens d’imagerie sont globalement identiques, et leur combinaison permet d’obtenir les meilleures performances. Actuellement, la technique du ganglion sentinelle est indispensable en cas de tumeurs mammaires T1-T2 N0 et en cas d’adénopathie suspecte échographiquement avec cytoponction ou microbiopsie négative.

Lymph drainage of the upper limb and mammary region to the axilla: anatomical study in stillborns

PURPOSE

We studied the lymphatic drainage of the upper limb and mammary region directing to the axilla to investigate whether independent pathways can be observed or whether anastomoses and shared drainage occur between them. This analysis aimed to assess the safety of axillary reverse mapping (ARM) in breast cancer treatment and to understand the development of lymphedema after sentinel lymph node biopsy (SLNB) alone.

METHODS

Seven unfixed stillborn fetuses were injected with a modified Gerota mass in the peri-areolar area, palm and dorsum of the hands, formalin fixed, and then submerged in 10% hydrogen peroxide solution. Microsurgical dissection was then performed on the subcutaneous cellular tissue of the upper limb, axillary region, and anterior thorax to expose the lymphatic vessels and lymph nodes.

RESULTS

The dye injected into the upper limb reached either the lateral axillary group, known to be exclusively responsible for upper limb drainage, or the anterior group, which is typically related to breast drainage. There was great proximity among the pathways and lymph nodes. Communicating lymphatic vessels among these groups of lymph nodes were also found in all studied cases.

DISCUSSION

Lymphedema remains a challenging morbidity in breast cancer treatment. ARM and SLNB aim to avoid unnecessary damage to the lymphatic drainage of the upper limb. However, our anatomical study suggests that ARM may have potential oncological risks because preserved lymph nodes may harbor malignant cells due their proximity, overlapping drainage pathways, and connecting lymph vessels among lymph nodes.