Axillary ultrasound in staging breast cancer: diagnostic accuracy and effect on subsequent axillary surgery - the Plymouth experience

Introduction

Routine axillary ultrasound and sampling of abnormal nodes began in Plymouth in 2005 for the staging of primary breast cancer.

Methods

We collected imaging and pathological data on 385 women with invasive breast cancer from before and after the introduction of axillary ultrasound.

Results

Without axillary ultrasound, 136 of 208 (65%) women underwent axillary node sampling (ANS) based on mammographic and clinical findings. The remaining 72 (35%) women had axillary clearance surgery (ANC). Following ANS, 29 (21%) were histologically positive, 27 having subsequent ANC. Of those who had initial ANC, 37 of 72 (51%) were positive.

In our study 177 axillary ultrasounds were performed, and 112 were normal. Of these, 32 (29%) had ANC, 14 (44%) being histologically positive. Following abnormal axillary ultrasound, 51 of 65 (78%) underwent ANC with 45 (88%) being positive.

There was no significant difference in primary tumour size or mean patient age between the groups before and after the introduction of ultrasound.

Statistical analysis shows significant reduction (P < 0.02) in the proportion of ANC in the ultrasound group and, importantly, a reduction in histologically negative ANCs (P < 0.01).

In our study, axillary ultrasound had a sensitivity of 54%, a specificity of 83%, a positive predictive value of 71% and a negative predictive value of 71%.

Conclusion

Introduction of axillary ultrasound was associated with less frequent ANC. Importantly, there has been significant reduction in histologically negative clearances. Our study supports the use of axillary ultrasound in guiding axillary surgical management.