Efficacy and safety of sequential immunotherapy following concurrent radiotherapy with S-1 in older patients with esophageal squamous cell carcinoma: an inverse probability weighting analysis

Sequential ICI therapy after CCRT significantly improved PFS and reduced mortality risk in older ESCC patients, though close monitoring is warranted for pneumonitis and skin-related toxicities. The reduced incidence of neutropenia suggests a hematologic safety advantage of the sequential strategy. Patients aged ≥75 years, with an Eastern Cooperative Oncology Group (ECOG) score of 2, or with N3 disease constitute high-risk subgroups and warrant individualized treatment approaches.