Margin assessment after neoadjuvant chemotherapy in invasive lobular cancer

Background: Optimal surgical management of patients with invasive lobular carcinoma (ILC) who undergo neoadjuvant chemotherapy (NAC) is unknown. We evaluated optimal margin distance and local recurrence (LR) rates for these patients. Methods: Ninety-three (30%) of 311 patients with ILC received NAC. We examined margin status, residual disease after re-excision, and clinical outcomes. Results: Margin positivity rates after the final operative procedure were similar between the NAC and surgery-first group (P > .05). The proportion of patients, stratified by margin status, who were taken back for re-excision was not different between the 2 groups, and, similarly, there were no differences in frequency of residual disease (all P > .05). At a median follow-up of 3.1 years, 1 patient in the NAC group and 2 in the surgery-first group developed LR (P = 1.0). Conclusions: Patients with ILC who have undergone NAC and have margins >1 mm have a low probability of residual disease and LR.