New Study Assesses Risk of Gastric Cancer in Adults Under 40

Incidence of gastric cancer has increased in people aged ≤40 years since 1980 in some countries, according to a new study published in JAMA Network Open.

“Gastric cancer is one of the most common cancers, with a high mortality-to-incidence ratio. It is uncertain whether developed nations may encounter an increasing burden of gastric cancer in young adults, as occurs for other cancers,” wrote the study authors.

Gastric Cancer in Younger Adults

The goal of this study was to compare the incidence and mortality of gastric cancer globally between patients aged older and younger than 40 years. The investigators used global and national cancer registries to evaluate gastric cancer incidence between 1980 and 2018 in 48 countries. Data sources included >15 calendar years of incidence and mortality information. The primary outcome was average annual percent change (AAPC) for incidence and mortality, evaluated via joinpoint regression analysis.

In 2018, 1,033,701 new cases of gastric cancer were recorded, and 782,685 gastric cancer-related mortalities occurred. The overall incidence since 1980 decreased in 29 countries, and mortality decreased in 41 countries.

Eastern Asia had the highest cumulative risk of gastric cancer incidence (2.64 percent) and mortality (1.84 percent). Southern Africa had the lowest risk of incidence (0.42 percent). Micronesia had the lowest risk of mortality (0.21 percent). There was a trend toward higher risk in countries with a higher Human Development Index.

Age-Standardized Risk of Gastric Cancer

Age-standardized incidence of gastric cancer was between 2.6-59.1 cases per 100,000 persons in 1980 and decreased to 2.5-25.8 cases per 100,000 persons in 2018. Age-standardized mortality decreased from 1.3-25.8 deaths to 1.5-18.5 deaths per 100,000 persons. The authors noted increasing mortality in Thailand (female AAPC, 5.3; male AAPC, 3.92; both P<0.001)

There was an overall decrease in gastric cancer incidence in most regions among adults aged >40 years. However, the authors noted an increase in incidence in populations aged <40 years in several countries. Incidence in younger adults increased for men in Sweden (male AAPC, 13.92; 95% confidence interval [CI], 7.16-21.11; P = 0.001), women in Ecuador (female AAPC, 6.05; 95% CI, 1.40-10.92; P = 0.02), and men and women in the United Kingdom (male AAPC, 4.27; 95% CI, 0.15-8.55; P = 0.04; female AAPC, 3.60; 95% CI, 3.59-3.61; P<0.001).

The authors concluded, “In this population-based cohort study, an increasing incidence of gastric cancer was observed in younger individuals in some countries, highlighting the need for more preventive strategies in younger populations. Future research should explore the reasons for these epidemiologic trends.”