Digestive cancer incidence and mortality among young adults worldwide in 2020: A population-based study

BACKGROUND: Digestive cancer has traditionally been thought of as a disease that mainly occurs in elderly individuals, and it has been ignored in young adults by both patients and physicians. AIM: To describe the worldwide profile of digestive cancer incidence, mortality and corresponding trends among 20–39-year-olds, with major patterns highlighted by age, sex, development level, and geographical region. METHODS: I performed a population-based study to quantify the burden of young adult digestive cancers worldwide. Global, regional, sex, and country-specific data estimates of the number of new cancer cases and cancer-associated deaths that occurred in 2020 were extracted from the GLOBOCAN Cancer Today database. To assess long-term trends in young adult digestive cancer, cancer incidence data and mortality data were obtained from the Cancer in Five Continents Plus database and the World Health Organization mortality database, respectively. The associations between the human development index (HDI) and digestive cancer burden in young adults were evaluated by linear regression analyses. RESULTS: In 2020, there were an estimated 19292789 new cancer cases, resulting in 9958133 deaths worldwide, which equated to an age-standardized incidence rate (ASIR) of 5.16 and age-standardized mortality rate (ASMR) of 3.04, accounting for 12.24% of all new cancer cases and 25.26% of all cancer deaths occurring in young adults. The burden was disproportionally greater among males, with male: female ratios of 1.34 for incidence and 1.58 for mortality. The ASIRs were 2.1, 1.4, and 1.0 per 100000 people per year, whereas the ASMRs were 0.83, 1.1, and 0.62 per 100000 people per year for colorectal, liver, and gastric cancer, respectively. When assessed by geographical region and HDI levels, the cancer profile varied substantially, and a strong positive correlation between the mortality-to-incidence ratio of digestive cancer and HDI ranking was found (R(2 )= 0.7388, P < 0.001). CONCLUSION: The most common digestive cancer types are colorectal, liver and gastric cancer. The global digestive cancer burden among young adults is greater among males and exhibits a positive association with socioeconomic status. The digestive cancer burden is heavy in young adults, reinforcing the need for primary and secondary prevention strategies.