First prospective multicenter Italian study on the impact of the 21-Gene Recurrence Score (RS) in adjuvant clinical decisions for ER+/HER2- early breast cancer (BC) patients.

Abstract

e12038 Background: The Breast-DX Italy prospective study evaluated the impact of the 21-gene RS on adjuvant treatment decisions for early BC patients. Methods: The study was conducted in 9 centers of the Veneto Region (2 hub and 7 spoke). All consecutive patients with ER+/HER2-, T1 to T3, N0 to N1 early BC who met protocol-defined clinicopathological criteria for “intermediate risk” were included. Pre-RS and post-RS physicians’ treatment recommendations and treatment actually received were collected. Results: From November 2014 to August 2016, n=124 N0 and n=126 N1 patients were enrolled (65% at hub and 35% at spoke centers). The majority had PgR+ (86%), G2 (71%) and pT1c (63%) BC. Median age was 55 yrs, median Ki67 was 20% (range 2-70%). The distribution of RS was: <18 (61%), 18-30 (32%) and >30 (7%). Main factors associated with higher RS were G3 and higher ki67. The addition of chemotherapy (CT) to hormonal therapy (HT) was initially recommended for 48% of the patients (38% of N0 and 57% of N1 patients; 54% and 37% of patients enrolled at hub and spoke centers, respectively). The post-RS recommendation changed from the pre-RS recommendation for 40 patients, mostly from CT+HT to HT (n=30; n=25 with low and n=5 with intermediate RS). Change was more frequent for N1 patients (Table). Of the 72 N1 patients initially recommended to CT+HT, 28% had a post-RS indication to HT alone. The crude number of patients with pre-RS recommendation to CT significantly exceeded the number of patients who finally received it (absolute difference =31; p<0.001). The majority of CT treatments were spared at hub vs spoke centers (n=24 and n=7, respectively). Conclusions: Pre-RS indication to HT alone was frequent, in particular for N0 patients and at spoke centers. The use of the 21-gene RS further contributed in sparing CT administration, more so for N1 patients and at hub centers. The impact of the RS when used at discretion of the clinicians is currently under investigation in the prospective ROXANE study. [Table: see text]