Preoperative conventional axillary ultrasound (AUS) and sonoelastography (SE) for predicting axillary lymph node metastasis in breast cancer patients.

Abstract

e12074 Background: Patients with operable breast cancer (BC) and clinically negative lymph nodes (CNLN) usually undergo sentinel lymph node biopsy (SNLB) or axillary lymph nodes dissection (ALND). AUS followed by fine-needle aspiration (FNA) or core-needle biopsy (CNB) could decrease number of unnecessary SNLBs and allow to assign patient to ALND directly. On the other hand, new AUS techniques such as SWE could enhance AUS specificity and allow to avoid SNLB in some patients. Aim: To assess sensitivity, specificity and negative predictive value of the AUS+SWE followed by FNA or CNB in patients with operable BC. Methods: Since Sep 2012 to Jan 2018 150 pts with operable BC and were enrolled. We include 30 pts in training cohort with clinically positive lymph nodes to verify AUS+SWE sensitivity and specificity. In validation cohort only those pts who were candidates for SNLB and who presented with tumor staging up to T3, and clinically negative axillae were included (n=120). All patients underwent preoperative AUS in B-mode, SWE, followed by FNA or CNB in case of suspicious nodes were detected. All pts underwent axilla surgery (SNLB = 46, ALND =74) and final pathology outcomes were available for all pts. Results: In training cohort of 30 patients with clinically positive lymph nodes the overall AUS+SWE sensitivity was set at 89.2%. The positive predictive value was calculated to be 96.1%. In the assessment of invasive breast tumors stages T1- T3 with clinically negative lymph nodes the sensitivity was 74.2%, specificity 95.5% positive predictive value was 85.2% and negative predictive value 91.4% If FNA or CNB follow the AUS+SWE in patients with CNLN the sensitivity was 86.7%, specificity 85.7% positive predictive value was 92.8% and negative predictive value was 75% (FNA or CNB was performed in 40 patients of 120 in validation set). Area under the ROC-curve was calculated as 0.860 [95% CI 0.766 to 0.954] for the US+SWE and 0.705 [95% CI 0.581 to 0.828] for the US+SWE followed by FNA or CNB. Conclusions: Axillary US+SWE should be included in the preoperative staging of all patients with invasive breast cancer. The addition US+SWE (not obviously followed by FNA or CNB) could lead to avoiding of unnecessary SNLB or ALND in patients with clinically and pathologically negative lymph nodes with negative predictive value of 91.4%. On the other hand in patients with US+SWE positive lymph nodes SNLB could also be skipped and the time interval to definitive therapy became shorter. Clinical trial information: BCA_US_SWE_001.