Correlations Between Oncotype DX Recurrence Score and Classic Risk Factors in Early Breast Cancer: Results of A Prospective Multicenter Study in Turkey.

Objective: Breast cancer is the most common malignancy among Turkish women and the rate of early stage disease is increasing. The Oncotype DX 21-gene assay is predictive of distant recurrence in ER-positive, HER2-negative early breast cancer. We aimed to evaluate the correlations between Recurrence Score (RS) and routine risk factors.

Materials and methods: Ten academic centers across Turkey participated in this prospective trial. Consecutive patients with breast cancer who had pT1-3, pN0-N1mic, ER-positive, and HER2-negative tumors were identified at tumor conferences. Both pre- and post-RS treatment decisions and physician perceptions were recorded on questionnaire forms. Correlations between RS and classic risk factors were evaluated using univariate and multivariate analyses.

Results: Ten centers enrolled a total of 165 patients. The median tumor size was 2 cm. Of the 165 patients, 57% had low RS, 35% had intermediate RS, and 8% had high RS, respectively. Multivariate analysis indicated that progesterone receptor (PR) and Ki67 scores were significantly related to RS.

Conclusion: Oncotype DX Recurrence Score does not seem to have a significant correlation with the majority of classic risk factors, but it may have a correlation with PR score and Ki67 score.