Surgeon Bias in the Management of Positive Sentinel Lymph Nodes

Background The standard of care for clinically node negative (cN0) patients following positive sentinel lymph node biopsy (SLN) was completion axillary 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 SLN. Method A single institution, retrospective review of cN0 patients with invasive primary breast cancer and positive SLN from 2010-2016 was performed. Patients with T4 disease, positive preoperative axillary biopsy, prior neoadjuvant therapy or axillary surgery were excluded. Patients with positive SLN undergoing CALND were compared to patients for whom CALND was omitted. Statistical analysis was performed using Kruskal-Wallis tests for continuous variables and Chi-squared tests or Fischer’s exact tests for categorical variables. Results Of 259 patients with positive SLN, 180 patients (69.4%) underwent mastectomy. CALND was performed at the time of mastectomy in 54 patients (30%), at time of second operation in 22 patients (12.2%), 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. Conclusion The management of cN0 patients with positive SLN 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.