P1.101. Treatment Selection and Real-World Outcomes of First-Line ICI-Based Therapy for Unresectable or Recurrent Esophageal Cancer in a Regional Hospital

Abstract

Abstract Topic Esophageal Cancer: Management of Metastatic Cancer Background Based on pivotal clinical trials, immune checkpoint inhibitors (ICIs) have demonstrated efficacy in patients with unresectable advanced or recurrent esophageal cancer and are now incorporated as standard treatment in the Japanese clinical practice guidelines. Although expanded therapeutic options are expected to improve survival outcomes, real-world data remain limited. Our institution is a regional hospital where a large proportion of patients are elderly, and esophageal cancer treatment is mainly managed by surgeons. This study aimed to evaluate real-world treatment selection and outcomes of ICI-based therapies at our institution. Methods We retrospectively analyzed 28 consecutive patients with unresectable advanced or recurrent esophageal cancer who received first-line ICI combined with chemotherapy (ICI+C) or dual ICI therapy (IO+IO) between July 2022 and December 2025 at a regional core hospital. Patient demographics, disease status (unresectable vs. recurrent), prior treatment history, renal function, treatment cycles, immune-related adverse events (irAEs), response rates, subsequent therapy, and overall survival were evaluated. Treatment responses were assessed in patients with measurable lesions according to standard radiological criteria. Overall survival was calculated from treatment initiation to death or last follow-up. Clinical characteristics and outcomes were compared descriptively between the two treatment groups. Results Nine patients received ICI+C (median age 80 years), and nineteen received IO+IO (median age 71 years). ICI+C was more frequently selected for unresectable disease and elderly patients. All ICI+C patients received dose-reduced 5-fluorouracil plus cisplatin. The median number of cycles was 11 in the ICI+C group and 2 in the IO+IO group. irAEs occurred in 33% and 68% of patients, respectively. Among evaluable patients, best responses (CR/PR/SD/PD) were 1/3/1/1 in the ICI+C group and 2/6/1/3 in the IO+IO group. Second-line therapy was administered in 4 and 6 patients, respectively. Median overall survival was 994 days in the ICI+C group and 391 days in the IO+IO group. Conclusion At our regional institution, ICI+C was more frequently selected for elderly patients with unresectable disease and achieved favorable tumor control and prolonged survival. In contrast, IO+IO was more often administered in recurrent cases and was associated with a higher incidence of progressive disease and irAEs, resulting in fewer treatment cycles. Notably, durable responses with a tail plateau pattern were observed in both groups, suggesting a meaningful survival benefit associated with the addition of ICIs in real-world clinical practice.