Sentinel Lymph Node Biopsy in Locally Advanced Breast Cancer After Neoadjuvant Chemotherapy-an Indian Perspective.

Sentinel lymph node biopsy (SLNB) alone in early breast cancer is an established standard of care. However, the same results have not been replicated in locally advanced breast cancer (LABC) after neoadjuvant chemotherapy (NACT). We aim to examine the feasibility of SLNB in LABC patients post NACT to determine identification rates (IR) and false negative rates (FNR). This was a single tertiary cancer center-based prospective study from February 2017 to November 2018. Forty-four patients with LABC (T3, T4 with N0 or N1) were studied and response after NACT was assessed. Only those patients who were N0 or who converted from N1 to N0 after NACT were included. Those patients who remained node positive after NACT directly proceeded with axillary dissection without SLNB and were excluded from the study. Demographic and clinical data is expressed in ratios and percentage and presented in table format. The median age at the time of study was 45.18 years. Most of the patients had T3 and above (97.7%) and N1 (86.3%) disease at the start of neoadjuvant therapy. The mean number of axillary lymph nodes dissected was 13.97. Dual method of sentinel lymph node mapping (methylene blue dye and radiolabeled colloid) was used in 26 (59.1%) patients. At least 1 SLN was identified in 86.4% patients with 100% identification in those patients in whom the dual method of SLN mapping was used. Median of 2 SLN was removed. Overall, false negative rate was 21.4%. FNR was high with the single method of SLN mapping (50% and 33.3% with methylene blue and radioactive colloid respectively) while it was considerably low when both were used simultaneously (11%). An average of 2 (range 0-4) SLN were identified and FNR were zero when 2 or more SLN were identified. Our study shows that SLNB in patients with LABC post NACT though viable cannot be recommended at present due to unacceptable high FNR. However, this should not dissuade us from exploring recurrence-free survival and overall survival associated with such IR and FNR albeit strictly under a clinical trial setting. © Indian Association of Surgical Oncology 2020.