Does ultrasound evaluation of the axilla increase the rate of axillary lymph node dissection in early stage clinically node negative breast cancer patients?

Background: Management and axillary staging of breast cancer has become less invasive and more conservative, over the decades. Considering Z011, axillary lymph node dissection (ALND) can be avoided in T1-2 N0-1 breast cancers with one or two positive sentinel lymph nodes (SLNs), if they are candidates for breast conserving surgery and radiotherapy. The aim of this study was to recognize if pre-operative axillary US evaluation in early-stage breast cancer could lead to more ALND in post Z011 era.

Method: 463 breast cancer patients were evaluated. 368 early-stage breast cancer patients (T1-2 N0) were included. We did not perform axillary US in early stage clinically node negative patients; however, 97 patients had axillary US prior to our visit. If axillary US could detect more than two suspicious LNs, US guided biopsy was performed. The remaining clinically node negative patients underwent upfront SLNB. ALND was performed if more than two SLNs were metastatic, or US-guided ALN biopsy proved metastatic involvement.

Results: 97 patients had axillary US evaluation before the surgery. 67 patients (69.2%) did not have any suspicious US detected axillary LNs, 17 patients (17.5%) had one, 7 patients (7.2%) had two, and 6 patients (6.2%) had more than two suspicious LNs according to their axillary US evaluation. Those with more than two suspicious LNs underwent ALN US-guided biopsy. Metastatic involvement of the LNs was proved in all of them and they underwent upfront ALND. ALND revealed more than 2 metastatic LNs in 2/6 patients (33.3%). 91 patients who were evaluated by axillary US, had less than two US detected suspicious LNs and underwent SLNB. Amongst 24 patients with one or two US detected suspicious LNs, 1/24 patient had more than two positive SLNs and underwent ALND. In this group 15.6% underwent ALND and 5.2% of them were unnecessary according to the recent guidelines. Axillary US had a false positive rate of 36.6%. The sensitivity of axillary US in distinguishing patients with more than two suspicious LNs in clinically node negative patients was 25%. In the second group (without pre-operative axillary US evaluation), SLNB was performed. 204/272 patients (75%) did not have LN metastasis. 54/272 patients (19.9%) had one or two metastatic SLNs and according to Z011, ALND was omitted. 5.1% had more than two metastatic SLNs and underwent ALND.

Conclusion: US evaluation of the axilla in early stage, clinically node negative breast cancer patients, is not sensitive enough to recognize more than two metastatic ALNs. It leads to more unnecessary ALND. Despite the small number of patients in this study, these results question the rationale of axillary US guided biopsy in low burden (less than two) suspicious LNs. looking for an imaging modality with a higher sensitivity in detecting the Burdon of axillary metastatic involvement is mandatory.