111P Sentinel lymph node biopsy in post-neoadjuvant chemotherapy breast cancer patients using combination of fluorescein and blue dye versus blue dye alone: An interim analysis of a randomized controlled trial (SONAR-FB)

Abstract

Sentinel lymph node biopsy (SLNB) is a standard procedure to determine the axillary lymph node(ALN) status in node-negative breast cancer(BC). Due to cost constraints and limited availability, the radiocolloid is being used in very few centers in developing countries. Fluorescein is inexpensive, sensitive fluorescent dye. SLNB in post neoadjuvant chemotherapy (NACT), has shown a higher false-negative rate (FNR) and lower identification rate(IR) comparing early BC. We studied the SLN IR and FNR of a dual tracer method, fluorescein plus methylene blue(FB) over methylene blue alone(B) in post NACT patients. It is a prospective, single-center, parallel-arm randomized controlled trial. All clinical node-negative, non-metastatic BC patients after NACT were included. They underwent axillary ultrasonography (AUS) to assess the morphologic appearance of the ALN to categorize it into normal or suspicious nodes. All patients were randomized before surgery. In one group, SLNB was done by FB and the other group by B alone after confirmation of non-allergy to the respective dye/dyes. All patients underwent ALN dissection. The primary objectives were SLN IR and FNR and the secondary objective was AUS's accuracy in the assessment of ALN pathological status. Out of 230 BC patients, 133 patients received NACT. Only 42 patients had clinically negative nodes after NACT. SLNB by FB and B was done in 21 patients and 20 patients, respectively. SLN could be identified in 20 out of 21 patients by the dual tracer(95%). Out of 20 patients, fluorescent nodes were identified in 19 (90.4%%) while blue nodes could be identified in 16 (76.1%). In the B group, Blue nodes were identified in 16/20 patients(80.0%).FNR with dual tracer was 11.1%(1/09 ) and FNR with blue dye was 16.6%( 1/06 ). AUS had 92% accuracy. A dual tracer. FB has a better IR and lowers FNR than B alone in post NACT breast cancer patients. It can be used as a low-cost and effective alternative to other dual tracers in low and middle-income countries.Moreover, excellent visualization of a lymphatic pathway by fluorescein can guide tracing the SLN.