False negative rate of sentinel lymph node biopsy in multicentric and multifocal breast cancers may be higher in cases with large additive tumor burden.

We aimed to evaluate the feasibility of sentinel lymph node biopsy (SLNB) in multicentric/ multifocal breast cancer. In this prospective study, 23 women with multicentric/multifocal breast cancer underwent SLNB at our institution from April 2002 to February 2006. Presence of preoperative axillary metastases was confirmed by FNA. Patients underwent sub-areolar radiopharmaceutical injection +/- isosulfan blue to perform SLNB, then completion ALND. The false-negative (FN) rate of SLNB was determined based upon final pathology. Twenty women with multicentric and three with multifocal invasive carcinoma were enrolled. The SLN identification rate was 100%. The overall FN rate of SLNB was 15% (95% CI 0.0466, 0.4281). Both cases with FN SLNB had multicentric disease, pathologic stage III breast cancer and a larger tumor burden compared with the study population. SLNB using sub-areolar injection is feasible for patients with multicentric/multifocal breast cancer yet may be associated with a higher FN rate in patients with large additive tumor burden.