Sentinel lymph node biopsy (SLNB) is an accurate, safe method for determining the axillary lymph node status. However, insufficient evidence exists to support the recommendation of SLNB in patients who have had neoadjuvant chemotherapy (NAC) to downsize tumours and allow for breast conservation surgery. The present study aimed to use molecular approaches to evaluate the feasibility and accuracy of SLNB in patients treated with NAC prior to SLN mapping and surgery. A total of 50 consecutive patients with operable invasive breast carcinomas who had received prior NAC were assessed using the one-step nucleic acid amplification (OSNA) method. The rate of SLN identification was 100%. The OSNA assay showed that 29 patients (58%) were negative for SLN and 21 patients (42%) were positive. In 19 of these 21 patients (90.48%), the SLN was the only positive lymph node. No axillary lymph nodes metastases were observed in patients with isolated tumour cells or with micrometastases. The OSNA assay is a highly sensitive, specific and reproducible diagnostic technique that can be used to analyse SLNs following NAC. The total tumoral load may assist with predicting additional non-SLN metastases.
Keywords: breast; cancer; molecular; neoadjuvant chemotherapy; one-step nucleic acid amplification; sentinel node.