A novel approach for 21-genes testing associated with prognosis in Chinese patients with ER-positive/HER2-negative breast cancer: A real-world study.

Abstract

e12528 Background: We previously reported a Chinese version of 21-genes Recurrence Score (RS) provides reduction chemotherapy prescription in patients with ER-Positive/HER2-Negative node negative breast cancer, while Oncotype Dx was hardly to be reached. However, the impact on clinical outcome was not mentioned. Herein, we explored whether this 21-genes recurrence score (RS) impacted on prognosis in patients with this molecular subtype of breast cancer. Methods: From Jan 2013 to Aug 2018, 378 patients with ER-Positive/HER2-Negative early stage breast cancer were enrolled. All patients received a Chinese version of 21-genes RS test, which is a new method using RNA extracted from formalin-fixed paraffin-embedded tissue performed by SurExam Campany, Guangzhou, China. . The RS score for each patient was calculated based on expression level of 21-genes used in a prosperctively defined algorithm and calculate a recurrence score range from 0 to 100 and divided three risk groups according to TAILORs study.Distant metastases-free survival (DMFS) were correlated with the 21-genes RS by Kaplan-Meier (log-rank method), and Cox regression. Multivariable logistic regression was performed to determine factors correlated with RS testing and receipt of a high-risk RS. Results: Median patient age was 46 years (18 to 77 years). The Chinese version of 21-gene RS was generated for 378 patients: 61 (16.1%) low risk ( < 11), 241 (63.8%) intermediate risk (11 to 25), and 76 (20.1%) high risk (≥ 26). At a median follow-up of 40 months, the 4-year-rate of estimated DMFS was 100%, 98.7% and 92.9% in low risk, intermediate risk and high risk groups. Meanwhile, there was no difference in RFS among three risk groups. For all patients, 21-gene RS was associated with DMFS ( P = .021). In multivariable Cox regression models, 21-gene RS was independently prognostic factor of DMFS (hazard ratio, 5.375; 95% CI, 1.00 to 28.84; P = .05). Tumor size (>2cm vs ≤2cm, OR = 2.31, P = .005), high grade ( OR = 2.15, P = .013), ki67 index ( > 14% vs ≤14%, OR = 4.24, P = .002), progesterone receptor expression ( < 20% vs ≥20%, OR = 5.07, P < .001) were predictor of high risk of RS. Conclusions: The Chinese version of 21-genes RS is independently prognostic factor for DMFS patients with ER–positive/HER2-negative node negative breast cancer. Future study was needed to explore the impact of 21 gene RS on long-term prognosis.