Impact of Oncotype DX testing on adjuvant treatment decisions in patients with early breast cancer: a single-center study in the United Arab Emirates.

Aim: To evaluate the distribution of the Oncotype DX Recurrence Score (a validated prognostic/predictive tool in early-stage estrogen-receptor positive [ER+] breast cancer) and its impact on adjuvant treatment decisions in the United Arab Emirates.

Methods: A retrospective analysis of a single-center cohort.

Results: The analysis included 47 node-negative ER+ breast cancer patients with low-to-intermediate risk according to the St. Gallen criteria. The mean (SD) Recurrence Score result was 17.7 (8.0); 25 (53.2%), 19 (40.4%) and 3 (6.4%) patients had low, intermediate and high Recurrence Score results, respectively. Recurrence Score risk categories were concordant with risk groups according to the St. Gallen criteria in 23 patients (48.9%). Before testing, 24 patients (51.1%) were recommended endocrine therapy alone and 23 patients (48.9%) were recommended chemoendocrine therapy. After testing, 13 patients (27.7%; 95% confidence interval 16.3-42.4%) had a treatment change (from pretesting recommendation to posttesting actual treatment), and chemotherapy use decreased overall (from 48.9 to 25.5%; P = 0.0023, McNemar's test), and particularly in the low Recurrence Score category (from 56.0 to 8.0%; P = 0.0005, McNemar's test). After testing, the proportions of patients with chemoendocrine therapy recommendations differed significantly across the Recurrence Score categories (8.0, 36.8 and 100% in the low, intermediate and high Recurrence Score categories, respectively; P = 0.0012, Fisher's exact test). With an average follow-up of 31.2 months (range: 17-51), no locoregional/systemic relapses were observed.

Conclusion: This first decision impact study in a Middle Eastern country showed the significant effect of Oncotype DX testing on clinical practice, further demonstrating the consistent impact of such testing worldwide.