A phase III randomized controlled trial comparing local field with additional prophylactic irradiation in chemoradiotherapy for clinical-T1bN0M0 esophageal cancer: ARMADILLO trial (JCOG1904).

Chemoradiotherapy has been considered as one of the standard treatment options for clinical T1bN0M0 esophageal squamous cell carcinoma with organ preservation. However, 20% of patients develop locoregional recurrence after chemoradiotherapy, which requires salvage treatment including salvage surgery and endoscopic resection. Salvage surgery can cause complications and treatment-related death. Interestingly, chemoradiotherapy with elective nodal irradiation has been reported to reduce the locoregional recurrence of advanced esophageal squamous cell carcinoma. Hence, we are conducting a clinical trial to confirm whether modified chemoradiotherapy with elective nodal irradiation was superiority to that without elective nodal irradiation for the patients with cT1bN0M0 esophageal squamous cell carcinoma. The primary endpoint is major progression-free survival, defined as the time from randomization to the date of death or disease progression, excluding successful curative resection through salvage endoscopic resection. We plan to enroll 280 patients from 54 institutions over 4 years. This trial has been registered in the Japan Registry of Clinical Trials (jRCTs031200067).