Improvement of survival in advanced gastric cancer over 15 years: Real-world analysis by 5-year periods.

375 Background: The prognosis of advanced gastric cancer (AGC) has gradually improved with the development of systemic chemotherapy. Reports from high-volume centers and nationwide registries have demonstrated survival gains (Ogata, Ther Adv Med Oncol 2024; Hironaka, Gastric Cancer 2020; Digklia, WJG 2016). However, temporal trends in community-based hospitals remain insufficiently evaluated. Methods: We retrospectively reviewed patients with histologically or cytologically confirmed gastric or esophagogastric junction adenocarcinoma who initiated first-line chemotherapy at a community-based hospital between 2009 and 2024. Patients were stratified into three chronological cohorts: period A (2009–2014), B (2014–2019), and C (2019–2024). Overall survival (OS), defined as the time from initiation of first-line therapy to death, and time to treatment failure (TTF), defined as time to discontinuation of first-line therapy for any cause, were estimated by the Kaplan–Meier method and compared with the log-rank test. Multivariable Cox proportional hazards models were applied to evaluate independent prognostic factors, including treatment period and clinical variables (age, sex, PS, histology, peritoneal metastasis, etc). Results: Among 677 patients screened, 322 were eligible (A:131; B:86; C:105). Baseline characteristics were generally balanced, though median age was slightly higher in period C. Median OS improved sequentially from 9.2 months (95% CI, 7.9–12.2) in A, 10.7 months (95% CI, 8.7–13.8) in B, to 13.6 months (95% CI, 11.1–16.8) in C (p=0.016). Median TTF was 4.5, 4.4, and 5.0 months, respectively, with no significant difference. Subgroup analyses showed limited OS improvement without significance in patients with peritoneal metastasis, whereas a significant benefit was observed in those without. Patients with PS1–2 achieved a significant OS gain (p=0.007), while PS0 showed only a modest trend. Multivariable analysis confirmed later treatment period as an independent favorable factor, with a significant benefit in C vs. A (HR 0.69, p=0.024). The use of immune checkpoint inhibitors and molecular targeted agents increased markedly in period C. Conclusions: Survival outcomes of AGC improved over time even in a community-based hospital, consistent with reports from high-volume centers. The most pronounced benefit was observed in patients with PS1–2, underscoring that therapeutic advances, including novel agents and supportive care, have translated into real-world clinical practice. The lack of improvement in patients with peritoneal metastasis highlights an unmet need for this subgroup.