Prognostic Significance of Circulating Tumor Cells in Patients with Esophageal Cancer Who Attained Pathological Complete Response after Neoadjuvant Therapy.

Background: Pathological complete response (pCR) refers to the absence of residual tumor cells after neoadjuvant chemoradiotherapy (nCRT) and is associated with favorable outcomes. However, 25%-33% of such patients still experience disease recurrence. This study aimed to evaluate the prognostic value of circulating tumor cells (CTCs) for risk stratification in patients with esophageal carcinoma (EC) who achieved pCR following nCRT. Methods: We measured post-nCRT CTC counts in the peripheral blood of patients with EC who attained pCR after undergoing nCRT. The impact of CTC counts on survival was then analyzed, accounting for the potential confounding effects of established clinical and pathological risk factors. Results: The study included 24 patients, of whom 18 (75%) had detectable CTCs. The mean CTC concentration was 5.1 per mL of blood. Univariable Cox regression analysis showed that CTC count was the only independent predictor of disease-free survival (hazard ratio, 1.113; 95% confidence interval, 1.008-1.229; p=0.034). Receiver operating characteristic curve analysis determined an optimal cutoff value of 4.5 CTCs per mL. The 3-year disease-free survival rate was significantly higher in the low-CTC group (92.9%) than in the high-CTC group (50.0%, p=0.032). Conclusion: In patients with EC who achieve pCR following nCRT, CTC quantification may help identify those at increased risk of poor survival outcomes.