A component of lobular carcinoma in clinically lymph node–negative patients predicts for an increased likelihood of upstaging to pathologic stage III breast cancer

Physical examination and diagnostic imaging are often less precise in determining the extent of disease in invasive lobular carcinoma (ILC) relative to nonlobular histologies. Anecdotally, surgical axillary evaluation frequently reveals positive lymph nodes in clinically N0 patients with ILC; however, few studies quantify the likelihood of finding unsuspected disease at the time of surgery. In this study, we evaluate whether the presence of lobular histology increases the incidence of surgical upstaging to pathologic stage IIIA or greater in patients with a clinically node-negative axilla and positive sentinel lymph node (SLN) biopsy