Why Are Stomach Cancer Rates Rising in Younger People? 

Stomach cancer, also known as gastric cancer, occurs when cells grow abnormally in the stomach. Due to slow growth and lack of symptoms, upper abdominal cancers affecting the stomach, pancreas, aesophagus, liver and bile duct are often undetected in the early stages.

Stomach Cancer Statistics in Australia

According to statistics from Cancer Australia and the Australian Institute of Health and Welfare, new stomach cancer diagnoses are estimated to reach over 2,300 in 2021. The risk of diagnosis by age 85 is 1 in 119 or 0.84 %. Stomach and other abdominal cancers have higher death rates and poor prognoses. Currently, the 5-year survival rate for stomach cancer is 34 %.

At this time, there are no government-approved screening tools for stomach cancer available in Australia; however, healthcare practitioners emphasise prevention methods and awareness of symptoms.

A Hidden Trend

In 2018, a detailed study published in the Journal of the National Cancer Institute discovered a surprising trend for stomach cancer between the years 1980 and 2018. The study participants were divided into two age groups: over age 50 and under age 50. Examination of the combined data of both age groups indicated a decrease in the occurrence of stomach cancer overall. When the researchers looked at each age group individually, however, the incidence levels changed; stomach cancer rates increased in the under age 50 group.

Not only did stomach cancer occur more frequently in the younger group, but also more females were affected than males. This finding contradicted years of research indicating stomach cancer was more common in men.

A Follow-Up Study

Research published in the Journal of the American Medical Association in 2021 also used the stomach cancer data from 1980 to 2018. For this study, the age groups divided participants over age 40, and under 40. As with the 2018 results, the examiners found an increased incidence of the disease in the younger age group.

Additionally, the researchers looked at the incidence of stomach cancer at the global level, examining rates in 48 nations. Three countries were identified as having the highest rates of stomach cancer in participants under age 40: Sweden, the U.K. and Ecuador.

For each gender, stomach cancer rates were reported as increasing, decreasing or remaining stable in each country. For men, 29 countries had stomach cancer incidence decreases, and 23 nations showed reduced incidence rates for women. None of the 48 countries indicated increasing rates. 

Possible Causes of Rising Incidence Rates

Researchers speculated there were reasons for the increased incidence in younger people. Because many of the participants were born after 1950, those in the younger age group likely used antibiotics throughout their lives. Antibiotics are known to change the stomach’s microbiome, which includes all healthy and unhealthy bacteria. Unhealthy bacteria growth in excessive amounts may contribute to an increased risk of stomach cancer. 

In addition to antibiotic use, lifestyle risk factors for younger people include obesity and increased coffee consumption. The use of endoscopy has led to more stomach cancer diagnoses. Researchers suggest the resulting new cases could raise incidence rates.

Stomach Cancer Prevention

Both the 2018 and 2021 studies suggested increasing awareness of stomach cancer and teaching about prevention. For all age groups, recommendations are:

• Check for H. pylori infection
• Quit smoking
• Stop or decrease alcohol use
• Improve diet by adding more vegetables and fruit

For younger people, researchers identified three key interventions:

• Increase exercise
• Improve diet and reduce coffee intake
• Increase public awareness of stomach cancer

Conclusion

Stomach cancer research in 2018 and 2021 discovered a previously hidden trend in incidence rates. Although diagnoses continue to decline overall, the medical profession needs to monitor younger people. Doctors might include questions about family history of cancer and lifestyle habits. Above all, it is important to teach young patients about cancer signs and symptoms and encourage healthy lifestyles for cancer prevention.