J Breast Cancer.  2023 Apr;26(2):105-116. 10.4048/jbc.2023.26.e19.

Prediction of Oncotype DX Recurrence Score Using Clinicopathological Variables in Estrogen Receptor-Positive/ Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer

• Kim MC
• Kwon SY
• Choi JE
• Kang SH
• Bae YK

• KMID: 2541761
• DOI: http://doi.org/10.4048/jbc.2023.26.e19

Abstract

Purpose
Oncotype DX (ODX) is a well-validated multigene assay that is increasingly used in Korean clinical practice. This study aimed to develop a clinicopathological prediction (CPP) model for the ODX recurrence scores (RSs).
Methods
A total of 297 patients (study group, n = 175; external validation group, n = 122) with estrogen receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative, T1-3N0-1M0 breast cancer, and available ODX test results were included in the study. Risk categorization as determined by ODX RSs concurred with the TAILORx study (low-risk, RS ≤ 25; high-risk, RS > 25). Univariate and multivariate logistic regression analyses were used to assess the relationships between clinicopathological variables and risk stratified by the ODX RSs. A CPP model was constructed based on regression coefficients (β values) for clinicopathological variables significant by multivariate regression analysis.
Results
Progesterone receptor (PR) negativity, high Ki-67 index, and nuclear grade (NG) 3 independently predicted high-risk RS, and these variables were used to construct the CPP model. The C-index, which represented the discriminatory ability of our CPP model for predicting a high-risk RS, was 0.915 (95% confidence interval [CI], 0.859–0.971). When the CPP model was applied to the external validation group, the C-index was 0.926 (95% CI, 0.873–0.978).
Conclusion
Our CPP model based on PR, Ki-67 index, and NG could aid in the selection of patients with breast cancer requiring an ODX test.

Keyword

Breast Neoplasms; Drug Therapy; Ki-67 Antigen; Receptors; Progesterone; Recurrence