306 - Oncotype Dx® - The Sírio-Libanês Hospital Cancer Center Experience

Abstract

ABSTRACT Background The Oncotype Dx® recurrence score (RS) assay quantifies the risk of distant recurrence (rDR) and its use has increased despite the lack of prospective studies. Methods This is a cross-sectional study of consecutive patients (PTS) from our Institution with histologically confirmed invasive breast cancer (IBC) who underwent surgery with curative intent and in whom Oncotype Dx (ODx) was performed. The main objectives were to compare (1) the predicted rDR by RS and Adjuvant! (2) Risk allocation by RS and St Gallen Criteria and (3) the agreement between histological grading (HG) and RS. Results From October/2006 to April/2012, 105 PTS with ER positive IBC were evaluated. Median age: 55y. Sixty-eight (64.8%) were EC IA; axillary lymph node involvement was seen in 25 PTS (14 micro and 11 macrometastasis). The rDR by RS was low in 64 PTS (60.9%), intermediate in 34 (32.4%) and high in 7 (6.7%). According to Saint Gallen, 12 (12%), 68 (68%) and 20 PTS (20%) were classified as low, intermediate and high risk, respectively, among 100 classifiable PTS. There was no statistically significant agreement between risk allocation by RS and Saint Gallen criteria (Kappa coefficient = -0.043; p = 0.401). Ki-67 data was available for 89 PTS: Conclusions We found no statistically significant agreement between Oncotype Dx®, the Saint Gallen criteria, Adjuvant!Online, or Ki-67. However, a potential association between HG and RS was noted. The rDR may be overestimated by clinicopathological-based classifications Disclosure All authors have declared no conflicts of interest.