Oncotype Dx score associated to pathological features to better prognosticate the risk of recurrence for breast cancer patients.

Abstract

e12562 Background: Oncotype Dx (ODX) prognosticates the risk of recurrence and predicts the benefit of adjuvant chemotherapy in estrogen-receptor-positive breast cancer (BC). However, it puts aside important clinical features. Our objective is to develop a model that uses routine clinical parameters associated with Oncotype Dx score to estimate the recurrence rate in our population. Methods: We retrospectively reviewed ODX and pathology reports from 371 early BC patients diagnosticated between 2014 and 2016 in a specialized cancer center, with a 5 year follow up. Variables were selected first with a univariate cox regression, then the statistically significant variables underwent a multivariate cox regression. The β coefficients from selected variables were used to create the prediction formula. Results: Among the tested variables, ki67, estrogen receptor (ER) and ODx score were significantly associated with Recurrence. The linear predictor is: (0.1331 x Ki67) + (0.4232 x ER)+(0.2112xODx score). The threshold score for this equation was set on 33 (median value) to discriminate low and high estimated risks for recurrence. The correct classification rate (CCR) for the training and validation sets was 76% and 68%, respectively. Conclusions: It is possible to optimize the Oncotype Dx to better determine a recurrence score with selected pathological features.