Prediction of the high-risk oncotype Dx recurrence score from clinicopathologic factors: A report from a cancer reference center in Brazil

Background: Oncotype DX Recurrence Score (ODXRS) is a 21-gene test that has been validated as an assay to effectively predict recurrence and chemotherapy benefit for hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) and lymph node negative (pN0) breast cancer. It has also been used in patients with 1-3 positive lymph nodes (pN1) in clinical practice. Methods: A single-institution retrospective study was conducted to include all patients who had an ODXRS test in our cancer center from 2005 to 2019. Clinical and pathology data were extracted from electronic charts. The predicted ODXRS was recorded and correlated with selected clinicopathological characteristics potentially related to a high-risk profile. A multivariate logistic regression model was performed to identify independent predictors of high-risk ODXRS (≥26) and ROC analysis was done to provide performance of the final model, found through exhaustive screening using Information Criteria (AIC). Associations with p Results: Two hundred and seventy-five patients with estrogen receptor positive, HER2 negative, pN0 or pN1 breast cancer were included. Median age was 55 years (range, 29 - 79). The ODXRS was low ( 25) in 58 (21.1%), 178 (64.7%) and 39 (14.2%) patients, respectively. On univariate and multivariate analyses, progesterone receptor negative status (p Conclusions: In our study, a prediction model based on progesterone receptor status, histological grade and KI-67 proliferation rate can be used to predict high-risk ODXRS. In resource-constrained healthcare systems, such model might help identify high-risk patients who would benefit from adjuvant chemotherapy without incurring the costs of the ODXRS test. Citation Format: Leandro JonataCarvalho Oliveira, Thais BacciliCury Megid, Marina Sahade, Andrea Kazumi Shimada, Daniele Xavier Assad, Joao Vicente Horvat, Antonildes Nascimento Assuncao, Artur Katz, Max Senna Mano. Prediction of the high-risk oncotype Dx recurrence score from clinicopathologic factors: A report from a cancer reference center in Brazil [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-47.