This study is a multi-center, non-interventional study. Patients' background, treatment pattern, treatment outcome, efficacy will be collected in metastatic esophageal squamous cell carcinoma (ESCC) patients who were treated with ICIs as 1st line treatment at approximately 26 institutions. The patients should have received at least 1 cycle of anti-PD-1 immunotherapy with or without radiotherapy. Based on these data, overall survival (OS), progression free survival (PFS) from start of 1st line treatment and the role and efficacy of radiotherapy for these patients will be assessed.
This study is a multi-center, non-interventional study. Clinicopathologic, treatment , outcome and efficacy data will be collected from medical records in metastatic esophageal squamous cell carcinoma (ESCC) patients.