Correlation of circulating or disseminated tumor cells with the Oncotype DX Recurrence Score

New biomarkers are emerging to predict recurrence risk in women with early-stage breast cancer. High Oncotype DX Recurrence Score® (RS) is associated with worse disease-free and overall survival. Similarly, circulating tumor cells (CTCs, blood) and disseminated tumor cells (DTCs, bone marrow) have prognostic value in breast cancer. We investigated the association between high RS and CTCs or DTCs.

Using a prospective database, we evaluated patients with hormone receptor-positive/HER2-negative, node-negative invasive breast cancer from 1/2005 to 1/2017. RS was classified using TAILORx study cutoff points: low (< 11), intermediate (11-25), and high (> 25). CTCs were assessed using CellSearch® and DTCs using cytospin specimens of bone marrow aspirates. Positive result was defined as one or more CTCs or DTCs identified. Chi-square analyses were utilized to evaluate the relationship between RS and CTCs or DTCs.

233 patients were identified from a prospective database, of which 96 had RS results. Of these patients, 88 had CTC results and 58 had DTC results. CTCs were detected in 17/88 (19%) patients, while DTCs were detected in 20/58 (34%). Patients with high RS were not more likely to have CTCs (18%) compared to patients with low/intermediate RS (20%; p = 0.919). Similarly, high RS was not associated with DTC detection, with DTCs present in 40% of patients with high RS versus 33% with low/intermediate RS (p = 0.687). In the subgroup of patients ≤ 50 years, no associations were found between high RS and CTCs (p = 0.383) or DTCs (p = 0.234).

High Oncotype DX RS did not correlate with CTCs in blood or DTCs in bone marrow in our study.