Abstract P1-01-32: Usefulness of Clinical Exploration, Ultrasound and MRI for the Assessment of Axillary Lymph Nodes Status Previous to the Performance of Sentinel Node Depends on Tumor Molecular Subtype

Abstract

Abstract Introduction: A high detection of positive lymph nodes previous to the surgical procedure lowers the probability of a false negative sentinel node. The sensibility and specificity of different imaging methods could depend on the molecular features of each tumor Objective: The aim of this study was to study sensibility and specificity of clinical exploration, ultrasound and MRI to assess the status of axilar lymph nodes in different molecular subtypes. Material and Methods: we retrospectively reviewed T1 and T2 breast cancers not candidate for neoadjuvant chemotherapy, treated in our breast cancer unit from September 2008 to May 2010. Data on clinical exploration (CE), axillary ultrasound (AU) and MRI were reviewed for each patient. The pathology exam of the surgical specimen (sentinel node or lymph node dissection) was reviewed for each patient and sensibility and specificity were calculated for each exploration method. Sensibility and specificity were also calculated separately considering five different molecular subtypes: Tubular A, Tubular B, Triple negative tumors, cerbB2 positive tumors and lobular tumors. Results: 290 patients with T1 and T2 breast cancer were included in the study. Sensibility for CE was 26.76% and specificity 91%. Sensibility for AU was 38.46% and specificity 86.81%. Sensibility for MRI was 44.06% and specificity 86.02%. For Tubular A tumors, the highest sensibility was for MRI (40%) and the best specificity for CE (91.35%). For Tubular B tumors, the highest sensibility was for CE (33.33%) and the highest specificity for AU (100%). For Triple negative tumors, the highest sensibility was for MRI (100%) and the highest specificity for CE (89.47%). For cerbB2 tumors, the highest sensibility was for MRI (75%) and the highest specificity was for CE (100%). For Lobular tumors, the highest sensibility and specificity were for AU (50% and 93.33%, respectively). Conclusion: MRI is the exploration with a higher sensibility to assess the preoperative status of axillary lymph nodes considering all the tumors together and in Tubular A, Triple negative and cerbB2 positive tumors. MRI sensibility is specially high in Triple negative and cerbB2 positive tumors. When choosing different imaging methods to assess axilar status, molecular subtype should be considered. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-32.