Clinical Utility of Circulating Tumor Cells for Predicting Major Histopathological Response after Neoadjuvant Chemoradiotherapy in Patients with Esophageal Cancer.

Abstract

Background: A “surgery as needed” approach may be offered to patients with esophageal cancer (EC) who achieve major histopathological response (MaHR) after neoadjuvant chemoradiotherapy (nCRT). However, the utility of clinical response assessment (CRE) for predicting histopathological response to nCRT remains limited. Circulating tumor cells (CTCs) hold promise as biomarkers of response to nCRT. Methods: We analyzed the clinical utility of post-nCRT CTCs, alone or in combination with CRE, in the prediction of MaHR. We defined MaHR as either the lack or a limited presence (≤10%) of vital residual tumor cells in the resected esophageal specimen in the absence of nodal involvement. Results: Of the 48 study patients, 27 (56%) achieved MaHR. Patients with MaHR had a significantly lower CTCs count compared with those without (3.61 ± 4.53 versus 6.83 ± 5.22 per mL of blood, respectively; P = 0.027). Using a cutoff for positivity of 5 CTCs per mL of blood, the combination of CTCs and CRE allowed achieving a negative predictive value for MaHR of 93% (95% confidence interval [CI] = 70–99%) along with a false negative rate of 5% (95% CI = 1–33%). Conclusion: CTCs count assessed in combination with CRE can potentially help identify patients with EC who achieved MaHR after nCRT.