Treatment decisions in estrogen receptor-positive early breast cancer patients with intermediate oncotype DX recurrence score results

This retrospective study evaluated the impact of intermediate Recurrence Score(®) results on adjuvant treatment decisions in estrogen receptor-positive (ER+) early invasive breast cancer, comparing treatment recommendations pre-testing with actual treatments received post-testing. Of the 111 patients included in the analysis, 78 (70.3%) had hormonal therapy (HT) and 33 (29.7%) had chemohormonal therapy (CHT) recommendations pre-testing. The Recurrence Score was significantly higher in those with a pre-testing CHT recommendation compared with those with a pre-testing HT recommendation (median of 24 vs. 22; P = 0.047; Mann–Whitney–Wilcoxon [MWW] test). Post-testing, treatment of 24 patients (21.6%) was different from their pre-testing recommendation. The difference between CHT recommendation rate pre-testing and the rate of CHT received post-testing was nonsignificant for the entire cohort and for patients’ subgroups (by age, tumor size, and grade) (P >0.17; McNemar’s test). Following classification of the cohort into two Recurrence Score subcategories (low-intermediate, [18-25]; high-intermediate, [26-30]), changes in treatment decisions (pre-testing recommendations vs. actual treatments received post testing) were reported for 16.5% of low-intermediate and 34.4% of high-intermediate patients. Post-testing, the rate of CHT decreased (by 58%) in the low-intermediate subcategory and increased (by 64%) in the high-intermediate subcategory (P <0.01, both subcategories). In logistic regression analyses, the Recurrence Score subcategory was the only significant predictor of changes in treatment decisions (pre-testing recommendations vs. actual treatments received post testing; P <0.01). The only significant difference between the two subsets of patients with such a change (HT to CHT, 11 patients; CHT to HT, 13 patients) was the Recurrence Score (median of 28 vs. 20, respectively; P = 0.0014; MWW test). These findings demonstrate that intermediate Recurrence Score results provide clinically relevant information and impact treatment decisions in ER + early breast cancer.