[Impact of the 21-gene recurrence score assay in clinical treatment and prognosis analysis for patients with hormone receptor positive early-stage breast cancer].

Objective To explore the association between the 21-gene recurrence score (RS) and clinicopathologic characteristics as well as prognosis in patients with axillary lymph node negative, hormone receptor (HR) positive breast cancer. Methods The clinicopathologic data of 439 early breast cancer patients who underwent 21 gene RS testing was retrospectively analyzed. According to the 21 gene RS, the patients were divided into low risk (295 cases), intermediate risk (111 cases) and high-risk (33 cases) group. The relationship between the 21 gene RS and clinicopathological characteristics, treatment, recurrence and metastasis was analyzed. Univariate and multivariate statistical analyses were used to analyze the risk factors for relapse free survival (RFS). Results Tumor grade, estrogen receptor (ER), progesterone receptor (PR) and Ki-67 index were significantly different among the 3 risk cohorts (P<0.001 for all). After a median follow-up of 32 months, the recurrence rate in low risk group (3.7%) was significantly lower than that in the intermediate-high risk group (9.0%), the locoregional recurrence (LRR) rate of low, intermediate and high risk group was 2.4%, 6.3% and 9.1%; and the distant metastasis (DM) rate in low risk group was 1.4% and 2.1% in the intermediate-high risk group. Univariate analysis showed RS, ER status and endocrine therapy were prognostic factors for RFS (P<0.05 for all). Multivariate analysis showed that RS was an independent significant predictor for RFS (P=0.04). Conclusions The 21-gene RS is related to tumor grade, ER, PR and Ki-67 index. RS is an independent risk factor for RFS in patients with hormone receptor positive early-stage breast cancer. Key words: Breast neoplasms; Prognosis; 21-gene assay; Recurrence score