Background Aim of the study is to evaluate the role of ultrasound guided fine needle aspiration cytology (FNAC) in the restaging of node positive breast cancer after preoperative systemic therapy (PST). Methods From January 2016 – October 2020 106 node positive stage IIA-IIIC breast cancer cases undergoing PST were included in the study. 18 (17 %) were carriers of pathogenic variant in BRCA1/2. After PST restaging of axilla was performed with ultrasound and FNAC of the marked and/or the most suspicious axillary node. In 72/106 cases axilla conserving surgery and in 34/106 cases axillary lymph node dissection (ALND) was performed. Results False Positive Rate (FPR) of FNAC after PST in whole cohort and BRCA1/2 positive subgroup is 8 and 0 % and False Negative Rate (FNR) – 43 and 18 % respectively. Overall Sensitivity − 55 %, specificity- 93 %, accuracy 70 %. Conclusion FNAC after PST has low FPR and is useful to predict residual axillary disease and to streamline surgical decision making regarding ALND both in BRCA1/2 positive and negative subgroups. FNR is high in overall cohort and FNAC alone are not able to predict ypCR and omission of further axillary surgery. However, FNAC performance in BRCA1/2 positive subgroup is more promising and further research with larger number of cases is necessary to confirm the results.

The aim of the study was to evaluate the role of ultrasound guided fine needle aspiration cytology (FNAC) in the restaging of node positive breast cancer after neoadjuvant chemotherapy (NAC). From January 2016 – October 2018, 90 node positive stage IIA-IIIC breast cancer cases undergoing NAC were included in the study. The largest, most superficial and the most caudal axillary node metastasis confirmed by fine needle aspiration cytology (FNAC) was marked with clip. After NAC, restaging of axilla was performed with ultrasound and FNAC of the marked and/or the most suspicious axillary node. Of the 90 cases, 58 with available ultrasound guided percutaneous needle biopsy data were further evaluated. Axilla conserving surgery was performed in 37 of 58 cases and axillary lymph node dissection (ALND) in 21 of 58 cases. False Positive Rate (FPR) of FNAC after NAC was 12%, False Negative Rate (FNR) — 58%, sensitivity — 54%, specificity — 82%, accuracy 62%. FNAC after NAC had low FPR and was found to be useful in predicting residual axillary disease and to streamline surgical decision making regarding ALND. However, FNR was unacceptably high and FNAC alone was not able to predict ypCR and omission of further axillary surgery.