Abstract
Early-onset (15-49 years) gastrointestinal cancers are an emerging public health concern in China, yet national trend analyses remain limited. Drawing on data from the Global Burden of Disease 2021 study, we evaluated nationwide trends in the incidence and mortality of early-onset gastrointestinal cancers (esophagus, stomach, liver, colon and rectum, gallbladder and biliary tract, and pancreas) in China from 1990 to 2021 and projected future patterns through 2040 using Bayesian age-period-cohort models. Between 1990 and 2021, age-standardized rates for esophageal, stomach, and liver cancers declined markedly while those for colorectal and biliary tract cancers increased, and pancreatic cancer rates rose modestly. Mortality for upper-GI cancers fell substantially, whereas colorectal cancer deaths rose modestly, with the age-standardized mortality rate declining despite rising incidence. Projections suggest continued declines in upper-GI cancers, further increases in colorectal and biliary tract cancers, and a peak in the age-standardized incidence rate of pancreatic cancer around 2030. These divergent trends highlight an urgent need for targeted prevention and early-detection strategies focused on colorectal, biliary, and pancreatic cancers among patients aged 15-49 years in China.