Comparison of the sentinel node procedure between patients with multifocal and unifocal breast cancer in the EORTC 10981-22023 AMAROS Trial: Identification rate and nodal outcome

Introduction: Multifocal breast cancer is associated with a higher risk of nodal involvement compared to unifocal breast cancer and the drainage pattern from multifocal localisations may be different. For this reason, the value of the sentinel node biopsy ( SNB) procedure for this indication is debated. The aim of the current analysis was to evaluate the sentinel node identification rate and nodal involvement in patients with a multifocal tumour in the EORTC 10981-22023 AMAROS trial. Patients and Methods: From the first 4000 registered patients, 342 were identified with a multifocal tumour on histological examination and compared to a randomly selected control group of 684 patients with a unifocal tumour. The outcome of the SNB was assessed. Results: The sentinel node was identified in 96% of the patients with a multifocal tumour and in 98% of those with unifocal disease. In the multifocal group, 51% had a metastasis in the sentinel node compared to 28% in the unifocal group; and further nodal involvement after a positive sentinel node was found in 40% (38/95) and 39% (39/101) respectively. Conclusion: In this prospective international multicentre study, the 96% detection rate indicates that the SNB procedure can be highly effective in patients with a multifocal tumour. Though the tumour-positive rate of the sentinel node was twice as high in the multifocal group compared to the unifocal group, further nodal involvement after a positive sentinel node was similar in both groups. This suggests that the SNB procedure is safe in patients with multifocal breast cancer. (C) 2013 Elsevier Ltd. All rights reserved.