Prediction of high nodal burden with ultrasound and magnetic resonance imaging in clinically node-negative breast cancer patients

Abstract

Background: Although the role of axillary imaging has been redirected for predicting high nodal burden rather than predicting nodal metastases since ACOSOG Z1011 trial, it remains unclear whether and how axillary lymph node (ALN) characteristics predicts high nodal burden. Our study was aimed to evaluate the predictive value of imaging characteristics of ALNs at ultrasound and magnetic resonance imaging (MRI) for prediction of high nodal burden (≥3 metastatic ALNs) in clinically node-negative breast cancer patients.

Methods: Clinicopathological and imaging characteristics were evaluated in patients with ultrasound (n = 312) and MRI (n = 256). Imaging characteristics include number of suspicious ALNs and cortical morphologic changes (grade 1, cortical thickness < 2 mm; grade 2, 2-5 mm; grade 3, ≥5 mm or fatty hilum loss). Odds ratios (ORs) were calculated using multivariate analysis.

Results: For ultrasound, higher (≥2) T stage (OR = 5.65, P = .005), higher number of suspicious ALNs (2 suspicious ALNs, OR = 6.52, P = .019; ≥ 3 suspicious ALNs, OR = 21.08, P = .005), and grade 3 of cortical morphologic changes (OR = 9.85, P = .023) independently associated with high nodal burden. For MRI, higher (≥2) T stage (OR = 5.17, P = .011) and higher number of suspicious ALNs (2 suspicious ALNs, OR = 69.00, P = .001; ≥ 3 suspicious ALNs, OR = 93.55, P < .001) were independently associated with high nodal burden. Among patients with 2 suspicious ALNs, those with grade 3 cortical morphologic change at ultrasound had a higher rate of high nodal burden than those with grade 2 (60.0% [3/5] vs. 25.0% [2/8]).

Conclusions: A higher number of suspicious ALNs is an independent predictor for high nodal burden. Further stratification can be achieved by incorporating assessment of ultrasound-based cortical morphologic changes.

Keywords: Axilla; Axillary nodes; Breast cancer; Lymph nodes; Magnetic resonance imaging; Ultrasound.

Fig. 1

Flow chart showing the relationship among ultrasound-based number of suspicious ALNs, cortical morphologic changes, and high nodal burden

Fig. 2

A 59-year-old woman diagnosed with invasive ductal carcinoma. a A confirmed, 1.2-cm malignant mass was observed in the upper inner quadrant of the left breast. b Two suspicious axillary lymph nodes (ALNs) were observed in the ipsilateral axilla. The most suspicious ALN (arrow) exhibits grade 3 cortical morphologic change with fatty hilum loss. This patient was confirmed to have high nodal burden, with 5 metastatic ALNs out of 18 ALNs

Fig. 3

A 37-year-old woman diagnosed with invasive ductal carcinoma. a A confirmed, 2.3-cm malignant mass was observed in the upper inner quadrant of the left breast. b Two suspicious axillary lymph nodes (ALNs) were observed in the ipsilateral axilla. The most suspicious ALN (arrow) exhibits grade 3 cortical morphologic change with fatty hilum loss. This patient was confirmed to have high nodal burden, with 10 metastatic ALNs out of 10 ALNs