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.

e12038Background: 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: 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;...