Management and Outcomes in Patients with Breast Cancer with 1-of-1 and 2-of-2 Positive Sentinel Nodes

The ACOSOG-Z0011 and AMAROS trials showed that axillary lymph node dissection (ALND) provided no benefit for patients with 1-2 positive sentinel lymph nodes (+SLNs). There remains apprehension to omit ALND for patients in whom only 1-2 SLNs are retrieved and all are positive. This study evaluates current practices and pathological findings when ALND is pursued.

We identified female patients with cT1-3N0 breast cancer who underwent sentinel lymphadenectomy from 2018 to 2021 in the National Cancer Database (NCDB). Patients with ≤ 2 SLNs were included and categorized on the basis of the number positive/removed: 0/1, 1/1, 1/2, and 2/2. We assessed the rates and factors associated with ALND.

A total of 102,802 patients were included: 0/1: 79,106 (77%), 1/1: 10,549 (10%), 1/2: 10,068 (10%), and 2/2: 3079 (3%). ALND was most frequently performed for patients with 2/2 +SLNs (41%), followed by 26% with 1/1 +SLNs, 19% with 1/2 +SLNs, and 6% with 0/1 +SLNs. On multivariable analysis, 2/2 +SLN status was the strongest independent predictor of ALND. For triple-negative and human epidermal growth factor receptor (HER)2+ patients, ALND did not affect adjuvant chemotherapy or radiation rates. Among pN+ hormone receptor (HR)+/HER2- patients > 50, ALND was linked to higher chemotherapy rates in all SLN groups, despite no difference in 21-gene recurrence scores. With a median follow-up of 35.4 months, ALND did not improve overall survival.

ALND is being performed at higher-than-expected rates in patients with ≤ 2 +SLNs and may contribute to adjuvant overtreatment, particularly in HR+/HER2- patients. Multidisciplinary case discussions and ongoing provider education are essential to reduce unnecessary axillary interventions.