A Multicenter Prospective Study Evaluating Concurrent Chemoradiotherapy Following Induction Immunochemotherapy for Esophageal Cancer Based on Dynamic ctDNA Monitoring

Esophageal squamous cell carcinoma (ESCC) continues to exhibit high incidence and mortality rates in China, with the majority of patients diagnosed at middle to advanced stages. Concurrent chemoradiotherapy (CCRT) is the standard treatment for unresectable locally advanced ESCC. The 5-year survival rate for advanced esophageal cancer remains below 20%. Immunotherapy has demonstrated definitive efficacy and a favorable toxicity profile in advanced ESCC, and preliminary results of its combination with radiotherapy have been reported. Induction immunochemotherapy followed by concurrent chemoradiotherapy represents a feasible combined treatment strategy. However, optimal biomarkers to identify patients who would benefit from this approach are still lacking. Circulating tumor DNA (ctDNA) status can accurately guide treatment implementation and predict tumor progression. Studies have shown that ctDNA changes precede imaging evidence of recurrence or metastasis, and ctDNA detection can sensitively predict tumor progression and prognosis. Therefore, it is necessary to dynamically monitor ctDNA changes throughout the course of induction immunochemotherapy followed by radical concurrent chemoradiotherapy in esophageal cancer and explore its correlation with prognosis.