UvA-DARE ( Digital Academic Repository ) Sentinel Node Identification Rate and Nodal Involvement in the EORTC 10981-22023 AMAROS

Background. The randomized EORTC 10981-22023 AMAROS trial investigates whether breast cancer patients with a tumor-positive sentinel node biopsy (SNB) are best treated with an axillary lymph node dissection (ALND) or axillary radiotherapy (ART). The aim of the current substudy was to evaluate the identification rate and the nodal involvement. Methods. The first 2,000 patients participating in the AMAROS trial were evaluated. Associations between the identification rate and technical, patient-, and tumor-related factors were evaluated. The outcome of the SNB procedure and potential further nodal involvement was assessed. Results. In 65 patients, the sentinel node could not be identified. As a result, the sentinel node identification rate was 97% (1,888 of 1,953). Variables affecting the success rate were age, pathological tumor size, histology, year of accrual, and method of detection. The SNB results of 65% of the patients (n = 1,220) were negative and the patients underwent no further axillary treatment. The SNB results were positive in 34% of the patients (n = 647), including macrometastases (n = 409, 63%), micrometastases (n = 161, 25%), and isolated tumor cells (n = 77, 12%). Further nodal involvement in patients with macrometastases, micrometastases, and isolated tumor cells undergoing an ALND was 41, 18, and 18%, respectively. Conclusions. With a 97% detection rate in this prospective international multicenter study, the SNB procedure is highly effective, especially when the combined method is used. Further nodal involvement in patients with micrometastases and isolated tumor cells in the sentinel node was similar—both were 18%. The concept of sentinel node biopsy (SNB) is based on an orderly pattern of lymphatic drainage from the primary tumor to regional lymph node basins. The first lymph node to which a tumor drains, the sentinel node, is detected with the aid of blue dye and/or a radioactive tracer and subsequently removed. The pathological status of the sentinel node is used to decide whether an axillary lymph node dissection (ALND) should be performed. Patients with a tumor-negative sentinel node can be spared a completion ALND and the associated side effects. In 1994, Giuliano et al. first reported the SNB procedure in breast cancer. The This study has been presented at the 31st San Antonio Breast Cancer Symposium, December 2009. The Author(s) 2010. This article is published with open access at Springerlink.com First Received: 19 June 2009; Published Online: 19 March 2010 M. E. Straver, MD, PhD e-mail: m.straver@nki.nl Ann Surg Oncol (2010) 17:1854–1861 DOI 10.1245/s10434-010-0945-z