Trends in gastric cancer incidence, mortality, and survival by histologic subtype in the United States (2000–2022) and a contemporary Chinese cohort

BACKGROUND: Gastric cancer is a major global health burden, but histologic subtype-specific epidemiologic and survival trends remain unclear. We aimed to characterize these trends in the United States and compare stage and survival in a Chinese cohort. METHODS: We analyzed data from the United States Surveillance, Epidemiology, and End Results (SEER) 17 registries (2000-2022) to estimate age-adjusted incidence, incidence-based mortality, and mortality-to-incidence ratio (MIR) for five histologic subtypes: gastric adenocarcinoma (GAC), gastric neuroendocrine tumor (G-NET), gastric neuroendocrine carcinoma/mixed neuroendocrine-non-neuroendocrine neoplasm (G-NEC/MiNEN), gastric carcinoma with squamous component (GCSC), and undifferentiated gastric carcinoma (UGC). Joinpoint regression was used to estimate average annual percent change (AAPC). Stage, 5-year overall survival (OS), and relative survival (RS) were assessed in SEER (2000-2017), and stage and 5-year OS in a Chinese cohort (2010-2020). RESULTS: From 2000 to 2022, the case composition of gastric cancer shifted by histologic subtype: GAC remained predominant but declined proportionally. Incidence decreased for GAC (AAPC, -1.74%) and GCSC (-1.37%) but increased for G-NET (4.37%) and G-NEC/MiNEN (3.67%). Mortality increased for G-NET and G-NEC/MiNEN, while MIR increased for GAC and G-NET. Stage distributions differed across subtypes. In SEER, 5-year OS was highest for G-NET (83.3%) and lowest for GCSC (12.3%). In the Chinese cohort, 5-year OS was higher for GAC (48.4%) but lower for G-NEC/MiNEN (22.4%) than in SEER, paralleling fewer stage IV GAC and fewer stage I G-NEC/MiNEN. CONCLUSIONS: Gastric cancer subtypes show distinct epidemiologic and prognostic patterns. IMPACT: These findings support histology-based prevention, early detection, and treatment strategies.