Prognostic Value of Circulating Exosomal DNA in Esophageal Squamous Cell Carcinoma: A Prospective Cohort Study.

Abstract

BACKGROUND: Reliable biomarkers for prognostication and recurrence surveillance in esophageal squamous cell carcinoma (ESCC) remain limited. The authors therefore investigated the potential clinical utility of exosomal DNA, which has emerged as a promising component of liquid biopsy. METHODS: This study screened 54 patients with ESCC. After exclusions, 210 blood samples from 21 patients underwent mutation-specific droplet digital polymerase chain reaction assays of plasma exosomal DNA (exoDNA) and circulating tumor DNA (ctDNA) before and after treatment. Kaplan-Meier and receiver operating characteristic analyses were performed to examine associations with overall survival (OS), disease-specific survival (DSS), relapse-free survival (RFS), and recurrence. RESULTS: Pretreatment exoDNA positivity was significantly associated with shorter DSS (p = 0.035) and shorter RFS (p = 0.048). Post-treatment exoDNA positivity was significantly associated with shorter OS (p = 0.0008), DSS (p = 0.0001), and RFS (p = 0.0001). Post-treatment ctDNA positivity was associated with shorter DSS (p = 0.038). CONCLUSIONS: In ESCC, exoDNA demonstrated prognostic and predictive value, supporting its potential role as a complementary biomarker for postoperative surveillance.