E12: Are Clinically Node-Negative Patients with a Positive Preoperative Axillary Lymph Node Biopsy Appropriate Candidates for Sentinel Lymph Node Biopsy?

ePoster Abstract Author(s)

Regina Matar-Ujvary, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Submitter(s)

Regina Matar-Ujvary, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Author(s)

VS

Varadan Sevilimedu, DrPH

Biostatistics Service, Department of Epidemiology and Biostatistics
Memorial Sloan Kettering Cancer Center, United States
Monica Morrow, MD

Breast Service, Department of Surgery
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Introduction: Whether cN0 patients with axillary nodal metastases identified by imaging are appropriate for sentinel lymph node biopsy (SLNB) or should proceed directly to axillary lymph node dissection (ALND) or neoadjuvant chemotherapy (NAC) is controversial. The American Society of Breast Surgeons guidelines recommend SLNB for patients with cT1-2N0 tumors regardless of preoperative imaging and biopsy results to avoid axillary overtreatment. To refine patient selection, we sought to identify factors associated with ≥ 3 positive SLNs after a positive preoperative lymph node (LN) biopsy.

Methods: Patients with cT1-2N0 breast cancer and a positive LN biopsy treated between 2014 and 2022 were identified from a prospective database. Patients receiving NAC were excluded. Clinicopathologic characteristics were compared between women with 1-2 positive SLNs and ≥ 3 positive SLNs.

Results: Between January 2014 and December 2022, 93 eligible patients were identified; 69 (74%) had 1-2 positive SLNs and 24 (26%) had ≥ 3 positive SLNs. Median patient age was 62 years (interquartile range [IQR] 53, 72), and median tumor size was 2.1 cm (IQR 1.4, 2.9). The median number of SLNs removed was 4 (IQR 3, 5). Seventeen women (18%) received a mastectomy and 26 (28%) underwent ALND following SLNB. Women with ≥ 3 SLNs were more likely to have > 1 abnormal LN on preoperative imaging (50% vs 28%; p = 0.04). There was no difference in BMI, tumor size, histology, grade, multifocality, presence of lymphovascular invasion, and receptor status between groups (Table). On multivariable analysis, having > 1 abnormal LN on preoperative imaging was significantly associated with ≥ 3 positive SLNs (hazard ratio [HR] 4.03, 95% confidence interval [CI] 1.36-12.8; p = 0.01).

Conclusions: Over 70% of women with cT1-2 breast cancer with non-palpable, biopsy-positive LNs had < 3 nodal metastases and do not require ALND. Frozen section of SLNs in those with multiple abnormal nodes on preoperative imaging can minimize the number of patients requiring a return to the operating room for completion ALND. While a positive node biopsy may be useful to triage HER2+ and triple-negative patients to NAC, it does not represent an indication for ALND.

Learning Objectives:

Identify the rate of ≥ 3 positive SLNs in women with cT1-2N0 breast cancer with positive preoperative lymph node biopsy.
Identify factors associated with an increased risk of needing an axillary lymph node dissection in women with cT1-2N0 breast cancers and a positive preoperative lymph node biopsy.
Stratify women with cT1-2N0 breast cancers and a positive preoperative lymph node biopsy who may benefit from intraoperative frozen section to minimize the need for return to the operative room.