Utility of assessing early tumor shrinkage as an efficacy predictor in patients with non–surgically indicated or recurrent esophageal cancer treated with nivolumab plus ipilimumab

Nivolumab plus ipilimumab combination therapy has been administered as a first-line treatment in Japan since 2022 for patients with unresectable progressive or recurrent esophageal cancer. The efficacy and safety of this immune checkpoint inhibitor (ICI) doublet therapy are now being evaluated, and it is necessary to identify populations that benefit from this treatment at an early phase after initiation. For patients not showing early benefit, changing as soon as possible to other therapeutic strategies could improve their survival outcomes. Therefore, we attempted to identify decision-making factors such as early tumor shrinkage (ETS) based on treatment experience with ICI doublet therapy.