Two Center Retrospective Comparison of Inpatient and Outpatient Treatment of Ici + Fp Therapy for Esophageal Cancer

Background 5-FU + cisplatin in combination with immune check point inhibitor (FP + ICI) is considered as one of the standard treatments for unresectable or recurrent esophageal cancer. The treatment is mostly carried out in inpatient setting due to the toxicity, and there are no reports on the safety and efficacy in outpatient setting. The purpose of this study is to evaluate the safety, feasibility, and effecacy of FP + ICI in outpatient setting. Methods Between January 2018 and September 2023, 54 unresectable/recurrent esophageal cancer patients treated with FP + ICI more than 3 months were included in this study. Clinical outcomes, adverse events, body composition and nutritional indicators were investigated retrospectively in 34 patients treated with inpatient setting (Group I) and 20 with outpatient setting (Group O). Results Comparing Group I and O, there are no significant differences in baseline characteristics; age, sex, recurrent/unresectable, ECOG-PS. Adverse events (≥Grade 3) were neutropenia: 16 vs. 6; anorexia: 5 vs. 2; acute kidney injury: 2 vs. 1; others: 8 vs. 9, and irAEs (≥Grade 2) were type 1 diabetes: 1 vs. 0; hypothyroidism: 2 vs. 1; skin rash: 2 vs. 1, respectively. Comparing the changes during the first 3 months, weight loss was 2.7 kg vs. 0.5 kg (p = 0.013), and psoas muscle index (PMI) reduction was 9.1% vs. 0.6% (p = 0.025), neutrophil lymphocyte ratio (NLR) improved by 15% vs. 35% (p = 0.036). Conclusion Outpatient FP + ICI is safely and feasible without reducing the therapeutic effects. This result suggests the possibility of preventing the loss of nutritional indexes during esophageal cancer treatment.