BCT score predicts chemotherapy benefit in Asian patients with hormone receptor-positive, HER2-negative, lymph node-negative breast cancer.

Mi Jeong Kwon,Jeong Eon Lee,Gyungyub Gong,Jong Won Lee,Sei Hyun Ahn,Peter D Beitsch,Sae Byul Lee,Byung-Ho Nam,Seok Jin Nam,Jinil Han,Young Kee Shin,William B Coleman

doi:10.1371/journal.pone.0207155

Abstract

The Breast Cancer Test (BCT) score has been validated for its ability to predict the risk of distant metastasis in hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer. This study aimed to examine the value of the BCT score for predicting the benefit of adjuvant chemotherapy for Korean women with hormone receptor-positive, HER2-negative, lymph node-negative breast cancer. The study included 346 patients treated with either hormone therapy alone (n = 203) or hormone therapy plus chemotherapy (n = 143), and compared patient survival between the two treatment groups. The effect of BCT score on patient survival by treatment group was assessed using Cox proportional hazards models. Based on the results, the BCT score was prognostic for distant metastasis-free survival and breast cancer-specific survival in the hormone therapy alone group. There was no significant difference between the treatment groups in terms of 10-year distant metastasis-free survival in the overall patient population. However, when patients were classified as low risk (n = 266) and high risk (n = 80) according to the BCT score, addition of adjuvant chemotherapy to hormone therapy for patients classified as BCT high-risk group led to a significant improvement in 10-year distant metastasis-free survival, from 65.4% to 91.9% (hazard ratio, 0.18; 95% confidence interval, 0.05–0.64; P = 0.003); in contrast, there was no benefit for the BCT low-risk group. The stratification of patients according to the BCT score also identified clinically high-risk patients who may not benefit from chemotherapy. Results were similar for breast cancer-specific survival. In conclusion, the BCT score was not only of prognostic value but was also a predictor of chemotherapy benefit for Korean patients with hormone receptor-positive, HER2-negative, lymph node-negative breast cancer.

Highlights

Adjuvant chemotherapy is used to reduce the recurrence risk of hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer; most patients with this condition are successfully treated with adjuvant hormone therapy alone without recurrence [1]
In a previous study [12], we developed and validated a novel prognostic model called the Breast Cancer Test (BCT) score to predict the risk of 10-year distant metastasis in patients with hormone receptor-positive, HER2-negative early breast cancer treated with hormone therapy alone
346 patients with hormone receptor-positive, HER2-negative, lymph node-negative breast cancer who were treated with either hormone therapy alone or hormone therapy plus chemotherapy at Asan Medical Center were included in the analysis

Summary

Introduction

Adjuvant chemotherapy is used to reduce the recurrence risk of hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer; most patients with this condition are successfully treated with adjuvant hormone therapy alone without recurrence [1]. The decision to include adjuvant chemotherapy alongside hormone therapy is based on traditional clinicopathological parameters such as tumor size and nodal status [1] or clinical factor-based tools such as Adjuvant! Several multigene molecular signatures, including the Oncotype DX 21-gene recurrence score, MammaPrint 70-gene signature, PAM50-based Prosigna risk of recurrence, and EndoPredict, have been developed to better predict recurrence or distant metastasis in patients with hormone receptor-positive early breast cancer [5, 6]. In a previous study [12], we developed and validated a novel prognostic model called the Breast Cancer Test (BCT) score to predict the risk of 10-year distant metastasis in patients with hormone receptor-positive, HER2-negative early breast cancer treated with hormone therapy alone. We assessed whether the BCT score can predict the benefit from adjuvant chemotherapy for patients with hormone receptor-positive, HER2-negative, lymph node-negative breast cancer

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