Surgeon Bias in the Management of Positive Sentinel Lymph Nodes

Abstract

Background: The standard of care for clinically node-negative (cN0) patients following positive sentinel lymph node biopsy (SLNB) was completion axillary lymph node dissection (CALND). Publication of ACOSOG Z0011 in 2010 changed this standard for patients undergoing lumpectomy. Clinicians have since expanded this practice to mastectomy patients, and ongoing prospective studies are seeking to validate this practice. Here, we evaluate patient and tumor characteristics that led surgeons to forego a second surgery for CALND in cN0 mastectomy patients with positive SLNB.

Patients and methods: A single institution, retrospective review of cN0 patients with invasive primary breast cancer and positive SLNB from 2010 to 2016 was performed. Patients with T4 disease, positive preoperative axillary biopsy, prior neoadjuvant therapy or axillary surgery were excluded. Patients with positive SLNB undergoing CALND were compared with patients for whom CALND was omitted. Statistical analysis was performed using Kruskal-Wallis tests for continuous variables and χ² tests or Fischer exact tests for categorical variables.

Results: Of 259 patients with positive SLNB, 180 (69.4%) patients underwent mastectomy. CALND was performed at the time of mastectomy in 54 (30%) patients, at time of second operation in 22 (12.2%) patients, and not performed in 104 (57%) patients. Delayed CALND was significantly associated with younger age, larger tumors, increased number of positive sentinel nodes, invasive lobular carcinoma, extranodal extension, and lymphovascular invasion.

Conclusions: The management of cN0 patients with positive SLNB that do not meet ACOSOG Z0011 criteria is evolving and is influenced by tumor and patient characteristics in an attempt to balance the morbidity of CALND with the low rate of local regional recurrence.

Keywords: ACOSOG Z0011; Axillary lymph node dissection; Axillary metastasis; Mastectomy; Sentinel lymph node biopsy.