Purpose Axillary ultrasound (AUS) is a standard procedure in the preoperative clinical identification
of axillary metastatic lymph node (LN) involvement and thereby guides local and systemic
therapy decisions in early breast cancer (EBC) patients. However, the interpretation
of AUS findings remains highly subjective, as a systematic definition for positive
LN in AUS has not been established yet. The aim of this study was to assess AUS performance
in the detection and exclusion of LN metastases by evaluating standardized sonographic
criteria.
Material and methods In a retrospective monocenter study n = 622 EBC patients were included who underwent
both AUS plus any type of axillary surgery, i.e. sentinel lymph node dissection and/or
(completing) axillary lymph node dissection. For all patients, AUS image documentation
of the most suspicious LN was saved during the initial diagnostic process and then
re-evaluated using pre-defined criteria for LN positivity. Main outcome measures were
sensitivity, specificity, accuracy, Youden-index (YI) and diagnostic odds ratio (DOR)
of the examined criteria.
Results Sensitivity and specificity of AUS were 53.3 % [46.4; 60.1] and 93.6 % [90.8; 95.8]
whereas accuracy of 79.7 % [76.4; 82.8], YI of 0.469 [0.398; 0.540] and a DOR of 16.75
[10.37; 27.05] were observed.
Conclusion AUS performance in clinical practice is currently not sufficient for accurately identifying
or excluding axillary metastatic disease. Although systematic criteria previously
recommended in literature were easily applicable and interrater-reliable, their application
did not substantially improve accuracy.
