A prospective validation study of sentinel lymph node biopsy in multicentric breast cancer: SMMaC trial.

Abstract Background Multicentric breast cancer is often considered a contra-indication for sentinel lymph node (SLN) biopsy due to concerns with sensitivity and false negative rate. To assess SLN feasibility and accuracy in multicentric breast cancer, the multi-institutional SMMaC trial was conducted. Methods In this study 30 patients with multicentric breast cancer and a clinically negative axilla were prospectively included. Periareolar injection of radioisotope and blue dye was administered. In all patients SLN biopsy was validated by back-up completion axillary lymph node dissection. Results the SLN was successfully identified in 30 of 30 patients (identification rate 100%). The incidence of axillary metastases was 66.7% (20/30). The false negative rate was 0% (0/20) and the sensitivity was 100% (20/20). The negative predictive value was 100% (10/10). Conclusion SLN biopsy in multicentric breast cancer seems feasible and accurate and should therefore be considered in patients with multicentric breast cancer and clinically negative axilla.