GLOBAL BURDEN OF YOUNG-ONSET GASTRIC CANCER: A SYSTEMATIC TREND ANALYSIS OF THE GLOBAL BURDEN OF DISEASE STUDY 2019

Objectives: While gastric cancer is declining overall, the global trend of young-onset (<40 years) gastric cancer remains uncertain. In this study we assessed the temporal trends of young-onset gastric cancer compared to late-onset gastric cancer (≥40 years).
Methods: We extracted cross-sectional data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. The burden of disease from 1990 to 2019 was assessed through incidence and mortality rates classified by global, national, and regional levels, and stratified by socio-demographic indexes (SDI), age, and sex groups. Joinpoint regression analysis was used to identify specific years with significant changes using a Monte Carlo Permutation method. The correlation between annual average percentage change (AAPC) in incidence and mortality with each country's average SDI was tested by Pearson’s Test.
Results: The global incidence rate of young-onset gastric cancer decreased from 2.20 per 100,000 in 1990 to 1.65 in 2019 with AAPC of -0.95 (95% confidence interval [CI]: -1.25 to -0.65; P<0.001). Late-onset cancer incidence also decreased from 59.53 per 100,000 in 1990 to 41.26 in 2019 (AAPC: -1.23; 95%CI: -1.39 to -1.06, P<0.001). Despite an overall decreasing trend, the incidence rate significantly increased from 2015 to 2019 for young-onset cancer (annual percentage change [APC]: 1.39; 95% CI: 0.06 to 2.74; P=0.041), whereas no upward trend was observed in late-onset cancer. Mortality rates of young- and late-onset cancer both exhibited a significant decline from 1990 to 2019 (AAPC: -1.82; 95% CI: -2.15 to -1.56; P<0.001 and AAPC: -1.69, 95%CI: -1.79 to -1.59; P<0.001; Figure 1). The male-to-female rate ratio for incidence and mortality in both age groups have been increasing significantly since 1990. While countries with high SDI have had a significant decline in the incidence of late-onset gastric cancer (slope of AAPC change: -0.20, P=0.004), the decline in young-onset cancer was not significant (slope of AAPC change: -0.11, P=0.130; Figure 2).
Conclusions: While the global incidence and mortality rates of both young- and late-onset gastric cancer have decreased since 1990., the incidence of young-onset cancer has demonstrated a significant upward trend since 2015. There were higher rates of decline in male and high SDI countries compared to females and low SDI countries, highlighting important disparities. These findings could help to inform future strategies in preventing gastric cancer, particularly in younger individuals.