475 - POST-NEOADJUVANT CHEMOTHERAPY RECURRENCE IN PATIENTS WITH NODE-POSITIVE BREAST CANCER: INFLUENCE OF DIFFERENT AXILLARY APPROACHES

Abstract

Introduction: Breast cancer treatment has drastically changed in recent decades due to a better understanding of the biology of this disease as well as an increase in diagnostic and therapeutic approaches. Axillary dissection (AD) persists as the
standard treatment for axillary nodes after neoadjuvant chemotherapy (NAC); however, sentinel lymph node biopsy (SLNB)
has become a promising alternative since it could spare the patient from lymphadenectomy-associated morbidity in axillary tumor regression following NAC. Objective: This study aimed to compare the recurrence rates between AD and SLNB
in initially node-positive patients treated with NAC. Methods: A retrospective review was conducted for medical records
of node-positive breast cancer patients treated with NAC at our institution between 2010 and 2016. Clinicopathological
and surgical variables including the types of axillary approach were collected. The SLNB was performed in those who
converted to node negative after NAC using technetium colloid, blue dye, or both. AD was performed in positive SLNB,
missing SLNB, or persistent clinically node-positive. The association of these variables with axillary or systemic recurrences was investigated using the χ2
test. Results: The study included 131 patients, being most patients (71%) diagnosed
with stage III disease. NAC produced a pathologic complete response in 22.1% of the patients. Axillary recurrence was
observed in 4 (3.1%) patients (including 1 patient who underwent SLNB and 3 who underwent AD), while systemic recurrence was occurred in 37 (28.2%) patients. Regarding the axillary approach, 26% of the patients underwent SLNB, 58% AD,
and 21% both techniques. A technetium-radiolabeled colloid and blue dye were both used as SLNB markers in 77.9% of
the patients. The sentinel lymph node identification rate was 91.5% and the mean number of lymph nodes removed was 3
in SLNB. None of the investigated factors were significantly associated with axillary recurrence. Patients who underwent
AD had higher systemic recurrence rates than those who only underwent SLNB. Conclusion: SLNB is a promising intervention for node-positive patients who convert to clinically node-negative status following NAC, since their recurrence
rate was not higher than that on patients who underwent AD.