To Dissect or Not to Dissect: Can We Predict the Presence of Four or More Axillary Lymph Node Metastases in Postmenopausal Women with Clinically Node-Negative Breast Cancer?

Background: Axillary lymph node (ALN) involvement is important for prognosis and guidance of multidisciplinary treatment of breast cancer patients. This study sought to identify preoperative clinicopathologic factors predictive of four or more pathologically positive ALNs in patients with cN0 disease and to develop a predictive nomogram to inform therapy recommendations. Methods: Using an institutional prospective database, the study identified postmenopausal women with cN0 invasive breast cancer undergoing upfront sentinel lymph node biopsy (SLNB) with or without completion ALND (cALND) between 1993 and 2007. Logistic regression analyses identified factors predictive of four or more positive nodes in the cN0 population and patients with one, two, or more SLNs. Results: The study identified 2532 postmenopausal women, 615 (24.3%) of whom underwent cALND. In the univariate analysis, tumor size, lymphovascular (LVI), histology, estrogen receptor (ER)-positive status, and multifocality/multicentricity were predictive of four or more positive nodes (n = 63; p < 0.05), and all except ER status were significant in the multivariate analysis. Of the 2532 patients, 1263 (49.2%) had hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative disease, and 30 (2.4%) were found to have four or more positive nodes. Of the 130 patients with exactly one positive SLN who underwent cALND (n = 130, 5.4%), 7 had four or more positive nodes, with grade as the only predictive factor (p = 0.01). Of the 33 patients with two or more positive SLNs who underwent cALND, 9 (27.3%) had four or more positive nodes after cALND, but no factors were predictive in this subset. Conclusion: Postmenopausal women with early-stage cN0 HR-positive, HER2-negative breast cancer with a single positive SLN had a very low risk (5%) of having four or more positive nodes on final pathology. With such a low risk of N2 disease, limited staging with SLNB may be sufficient to guide therapy decisions for this subset of patients.