Axillary lymph node status following non-identification of the sentinel lymph node in breast cancer

International guidelines provide no consensus on the surgical management of patients with sentinel lymph node (SLN) non-identification. This study aimed to identify factors associated with SLN non-identification and to determine axillary nodal status following axillary lymph node dissection (ALND) in contemporary clinical practice.

A retrospective cohort study included all patients with unilateral breast cancer who underwent sentinel lymph node biopsy (SLNB) at a tertiary university hospital between 2010 and 2022. All patients underwent preoperative ultrasound examination. SLNB was performed using both a radioisotope and blue dye, with preoperative lymphoscintigraphy. ALND was performed in cases of SLN non-identification.

SLN non-identification occurred in 86 out of 4233 (2.0%) patients. Higher BMI (p < 0.001) and day-before-surgery radiotracer injection (p < 0.001) were associated with SLN non-identification, whereas none of the tumor-related characteristics showed an association. Among patients with SLN non-identification, 68.6% were pN0 on histopathological examination, compared with 71.4% in patients with identified SLN (p = 0.57). Although a minor difference in nodal stage distribution was observed between pN + patients, the patients with high nodal burden were identifiable based on abnormal findings on preoperative ultrasound or palpably suspicious lymph nodes intraoperatively.

SLN non-identification was observed in 2.0% of patients and was not associated with presence of nodal metastases or tumor-related characteristics. Axillary management strategies to avoid ALND-associated morbidity should be considered, particularly in patients with normal preoperative ultrasound findings and no suspicious lymph nodes on intraoperative palpation.