Impact of a 21-Gene Recurrence Score Test on the Choice of Adjuvant Chemotherapy for Hormone Receptor-positive Early-stage Breast Cancer: A Prospective Study.

Zeng Y1, Li Q1, Qin T2, Li S1, Jin L1, Wu J1, Chen K1, Deng H1, Rao N1, Liu Q1, Su F1, Jia W3, Yao H3,2.

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Abstract

BACKGROUND:

Studies have recommended a 21-gene recurrence score (RS) to optimize adjuvant treatment for patients with early-stage breast cancer (EBC) with hormone receptor-positive (HR+) and human epidermal growth factor receptor-2 negative (HER2-) tumors. This study aimed to prospectively evaluate the impact of this RS in Chinese patients with breast cancer.

PATIENTS AND METHODS:

We prospectively collected 227 patients with EBC with estrogen receptor-positive (ER+) and HER2- tumors. We used one-way analysis of variance to compare the distribution of different risk groups based on a 21-gene RS assay. A Kruskal-Wallis test and either a chi-square or Fisher's exact test were used as appropriate to compare continuous and categorical variables, respectively.

RESULTS:

Of the 227 eligible women enrolled, 61.2%, 30%, and 8.8% of patients were in the low (≤17), intermediate (18-30) and high (≥31) RS groups, respectively. Of the patients with a low RS, 74.8% were overestimated into the intermediate-risk group by St. Gallen risk. The overall impact of the 21-gene RS was reduced use of chemotherapy (78/227, 34.4%). In addition, Ki67 expression was positively associated with the 21-gene RS (R=0.68).