Oncotype DX RS correlation with clinicopathologic risk factors and chemotherapy. Retrospective study in early stage ER positive breast cancer

Background: Oncotype DX risk score, a clinically validated test that estimates the recurrence and predicts the likelihood of benefit from adjuvant chemotherapy in early ER\PR positive, node-negative breast cancer, it is calculated based on characteristics of 21 genes that define the ER status, Her2 neu status, tumor proliferation, and tumor invasion. NCCN guidelines recommend adjuvant endocrine therapy for low RS (<18) and systemic adjuvant chemotherapy for high RS (>30), but no clear consensus about chemotherapy role in intermediate RS [18-30]. The aim of the study: Look for Oncotype Dx correlation, with clinicopathologic risk factors (age, tumor histology, tumor size, tumor grade, ER/PR status, tumor proliferation index) and chemotherapy. We did also evaluate how John Hopkins university recurrence score online tool can be utilized in filtering patient for Oncotype DX testing. Methods: Retrospective records review of approximately 54 patients who had Oncotype DX test during 2012-2017 in National Cancer Center–Qatar. Result: Of 54 patients studied 64.8% had low RS, 27.8% had intermediate RS, and 7.4% had high RS. Univariate analysis showed significant correlation with tumor grade (p<0.003), PR% status (cut-off 1%; p<0.016) and Ki67% (cut-off 20%; p<0.001). There was no significant correlation with patient age, tumor histology or tumor size. In multivariate analysis, only Ki67% predicted the Oncotype DX RS (p<0.028). JHU recurrence score had a moderate association with Oncotype DX RS at strength of agreement 0.524 (Cohen Kappa) Adjuvant chemotherapy treatment correlated significantly with the Oncotype DX RS in both univariate analysis (p < 0.002) and multivariate analysis (p < 0.003) Conclusion: Oncotype RS correlates significantly with the tumor grade, Ki67%, PR status, and chemotherapy treatment. JHU recurrence score has reasonable utility in filtering patient for Oncotype DX testing.