Temporal evolution of gastric adenocarcinoma in the United States, 2000–2023: Incidence, presentation, registry-recorded treatment, and survival

Background We assessed contemporaneous changes in gastric adenocarcinoma incidence, presentation, registry-recorded treatment, and survival. Methods Two complementary analyses used Surveillance, Epidemiology, and End Results (SEER) 17 data. Incidence during 2000–2023 was analyzed using Joinpoint regression. A clinical cohort diagnosed during 2004–2023 at prespecified stomach subsites (C16.1–C16.6, C16.8, and C16.9) was compared across four periods. Surgery trends were decomposed into stage-composition and within-stage components. Outcomes included overall survival (OS), cause-specific survival (CSS), and 36-month restricted mean survival time (RMST); adjusted Cox models separately summarized associations over 0–60 months. Results The clinical cohort comprised 66,391 tumor records from 66,025 patients. Incidence declined during 2000–2019 (annual percent change, −1.32%; 95% CI, −1.61% to −1.08%) and increased during 2019–2023 (4.96%; 95% CI, 2.51–9.91%). Comparing 2004–2008 with 2019–2023, distant-stage disease increased from 36.1% to 43.0%, whereas surgery among records with known surgery status decreased from 51.9% to 36.3%. Stage-composition change represented 25.7% of the surgery decline. Recorded chemotherapy increased from 35.7% to 54.4%. Median potential follow-up was 206.0 versus 27.4 months; latest-period fixed-time estimates were reported at 12 and 36 months. Three-year OS increased from 25.2% to 29.1% and CSS from 31.4% to 35.6%. Unadjusted 36-month RMST differences were 1.80 months (95% CI, 1.47–2.15) for OS and 1.86 months (95% CI, 1.53–2.22) for CSS. Conclusions Distant-stage presentation became more frequent while recorded surgery declined and short-term survival improved modestly. Within-stage changes represented most of the surgery decline. Additional registry years are needed to assess persistence of the post-2019 incidence increase.