Sentinel Node Biopsy in Post-neoadjuvant Chemotherapy Breast Cancer Patients Using Pre-chemotherapy Breast Tattooing.

The role of sentinel lymph node biopsy (SLNB) in locally advanced breast cancer (LABC) post-neoadjuvant chemotherapy (NACT) is debatable. We conducted a novel pilot study in which pre-NACT tattooing of breast lumps in LABC patients resulted in black tattoos being deposited in the axillary node. We hypothesized that this black node was the sentinel node. The identification rate (IR) of the black node in our pilot study was 100%, and the false-negative rate (FNR) was 0%. This study aims to evaluate our hypothesis that the black node is the sentinel node in post-NACT LABC patients after pre-NACT breast tattooing. This is a cross-sectional study of prospectively collected data of women with LABC undergoing surgery after NACT. Patients underwent tattooing of breast primarily using black tattoo ink prior to NACT. Women who progressed on NACT were excluded. All patients underwent axillary dissection. Intraoperatively identified black nodes were sent separately for pathological evaluation. The accuracy of the black nodes was assessed using IR and FNR. Of the 214 patients, a complete clinical response was present in 36%. Black node IR was 88.8% and FNR was 17.4%. In pre-NACT cN0 and cN1 patients, IR was 100% and 96.6%, and FNR was 0% and 4.63%, respectively. SLNB using pre-NACT tattooing in LABC patients has a high IR and FNR. In the subset with low pre-NACT axillary burden (cN0 or cN1), SLNB by pre-NACT breast tattooing has a high IR and low FNR.