Correlation between the Clinical Treatment Score Post 5 years (CTS5) and the Oncotype DX 21-gene recurrence score (ODX-RS); can we accurately predict patients who require extended adjuvant hormonal manipulation.

Background: . While hormone receptor-positive (HR+), HER 2-negative (HER2-), node-negative breast cancer is associated with an excellent overall prognosis, it possesses a unique penchant for late recurrence. Estimating breast cancer recurrence has traditionally relied on clinicopathologic markers, such as those underpinning the Clinical Treatment Score Post 5 years (CTS5) but there is an increasing dependence on multigene molecular signatures such as the Oncotype DX 21-gene recurrence score (ODX-RS). The purpose of this current study was to examine the relationship between the novel CTS5 and the ODX-RS with an observational cohort study. Methods: . The CTS5 and ODX-RS were calculated for 1,358 patients who were diagnosed with HR+, HER2-VE, node-negative, invasive breast cancer. The cohort was split according to menopausal status as defined by age. 381 pre-menopausal (<52 years) and 977 post-menopausal (≥ 52 years) patients were included in the analysis. Correlation statistics were used to investigate the relationship between the CTS5 and the ODX-RS. Results: . Considering the CTS5 and ODX-RS as categorical and continuous variables respectively, there was a significant relationship between the CST5 and the ODX-RS categories (Pearson's chi-squared ( x 2 ) p <0.001), and a high ODX-RS was weakly associated with a high CTS5 RS (Pearson product moment correlation pre-menopausal r=0.274, p<0.05; post-menopausal r=0.222, p<0.05). Conclusion: The current study demonstrates a weak but statistically significant correlation between the CTS5 and the ODX-RS that is independent of age. This finding mirrors previous research which indicates that the ODX-RS is poorly correlated with traditional clinicopathologic features used to predict recurrence risk.