Relationship of pathological features and a 21 gene expression assay in younger versus older women with node-negative endocrine receptor-positive breast cancer

Determining the need for adjuvant chemotherapy in estrogen receptor (ER)+ disease can be influenced by pathological characteristics and gene expression assays [i.e., Oncotype Dx recurrence scores (RSs)]. The primary objective of this study is to investigate the relationship between the RSs and pathological markers in younger ( 50) versus older (≥ 50) women with early-stage node-negative ER+ breast cancer.This was a single academic-center retrospective cohort study. Subjects who underwent Oncotype gene expression testing were retrospectively and sequentially identified. 436 Subjects were identified of which 344 were eligible for analysis (133 younger subjects 50 years of age, and 211 older subjects ≥ 50 years). Pathological data assessed included the progesterone receptor (PR), histological grade (grade), Ki-67, and P53. A multivariable regression analysis was performed using age, PR, and grade as predictor variables for RS. Adjusted RBased on the multivariable regression analysis, the adjusted RThe relationship between pathological features and RS is consistent irrespective of age; therefore, models predicting RS may be applicable irrespective of age.