Ultrasound of the axilla: analysing nodal cortical thickness

Introduction

Prognosis in breast cancer is dependent upon axillary lymph node status. For breast-conserving surgery, lymph node status can be assessed via sentinel lymph node procedures (SLNP) [1]. This can be time consuming, however, and it would be useful to identify a subset of quantitative nodal features on ultrasound in order to predict metastatic involvement and avoid the SLNP. Peer review states that cortical thickness is one of the best predictive characteristics [1, 2]. We wanted to interrogate our own data with a specific focus on this feature.

Methods

A retrospective study of 454 patients audited between August 2007 and October 2009. One hundred and thirty-seven had proven breast cancer and underwent axillary node sampling.

Results

In 75 cases the cortical thickness was recorded. Comparing with sentinel node biopsy or postoperative pathology, the results are as shown in Figure 1.

Figure 1

Cortical thickness in nodal disease.

Conclusions

The study confirms that the nodal cortical thickness correlates well with the presence of disease. It is easy to measure and appears to be a reliable indicator. Further, the minimum cortical thickness for positivity (27 mm) will help us to grade our degree of suspicion in future.