Impact Of Sentinel Lymph Node Biopsy In Breast Cancer Patients Treated With Neoadjuvant Chemotherapy

EPS 196 Aim/Introduction: To analyze how many of the patients undergoing neoadjuvant chemotherapy (NCT) may benefit from SLNB, as well as the impact on patient management, especially in those with early axillary involvement. Materials and Methods: We included patients with breast carcinoma candidates to NCT discussed at the Tumor Committee of our hospital (April/2017-August/2019). All of them were subjected to clinical assessment, ultrasound and, if appropriate, histological analysis, axillary pre and post- NCT. Sentinel lymph node detection was performed after periareolar injection of [99mTc]Tc-nanocoloid (74 MBq) the day before surgery. In some cases, blue dye was injected and/or a pre-NPC metal clip was placed in the affected node. Results: Sixty-two patients were included. NCT achieved a complete breast response in 12 patients, partial in 46 and non-response in 4. Initially, 31 patients were classified as N0 and 31 as N+ (28 N1 and 3 N2), achieving a complete axillary response in 58% of N+ (18). SLNB was performed in 49 patients (79%; 100% in N0 and 58% in N+ from baseline). The gamma detection rate of the sentinel lymph node was 91.8% (93.5% in N0 and 88.9% in N+). 28 lymphadenectomies were undergone (45.2%; 22.5% in N0 and 67.7% in N+), 11 due to positive SLNB (5 N0 and 6 N1), 13 owing to lack of axillary response and 4 caused by the non-localization of the sentinel lymph node. SLNB was performed in 58% of N+ patients, of which 44.4% were negative, avoiding lymphadenectomy. Metal clip and/or blue dye techniques were used in 31 cases (50%). Conclusion: SLNB is viable in a high percentage of patients with previous NCT, with a high detection rate, even in patients with early affected axilla, avoiding lymphadenectomy to patients who achieve a complete response of the axillary lymph node