Global Hotspots: The 5 Countries Hit Hardest by Stomach Cancer — And Why

Stomach cancer, or gastric cancer, remains a significant global health challenge. Although it ranks fifth among the most commonly diagnosed cancers worldwide, certain nations report much higher incidence rates than others. The World Cancer Research Fund (WCRF) and GLOBOCAN 2022 data lists the countries with the highest age-standardised incidence rates (ASR) per 100,000 people. These figures reveal the combined impact of diet, infection, access to screening, and healthcare infrastructure.

Mongolia ranks first globally in stomach cancer rates. In 2022, its age-standardised incidence rate reached 35.5 per 100,000, with men facing a particularly high burden at 53.0 per 100,000. The country’s traditional dietary habits, marked by smoked meats, salted dairy products, and preserved foods, play a central role in gastric mucosal damage, which facilitates carcinogenesis.

A critical contributing factor is the high prevalence of Helicobacter pylori, a bacterium that causes chronic gastric inflammation and is classified as a Group 1 carcinogen by the WHO. Studies suggest H. pylori infection affects over 70 percent of the adult population in Mongolia.

In addition, limited access to early detection and specialised oncology care results in late-stage diagnosis and high mortality. Rural populations often remain unaware of early symptoms, and national cancer screening programmes remain underdeveloped, further compounding the risk.

Japan continues to face a substantial burden from stomach cancer, with an ASR of 27.6 per 100,000. About 126,000 new cases were reported in 2022. Men in Japan have an ASR of 40.9, while women have a significantly lower rate of 15.9.

The main reasons for Japan's high stomach cancer rates lie in traditional dietary patterns, which include salty, pickled, and smoked foods such as miso soup, pickled vegetables, and salted fish. These foods create a harsh gastric environment and promote H. pylori colonisation.

Despite strong public health initiatives, H. pylori infection remains widespread, particularly in older generations. Japan’s ageing population further inflates the stomach cancer burden, as risk increases sharply with age.

Japan also maintains an extensive national screening programme for gastric cancer, employing techniques like endoscopy and barium meal testing, especially for individuals aged 40 and above. This leads to higher detection rates and thus higher reported incidence, but also contributes to better survival outcomes due to early-stage diagnosis.

South Korea ranks third, with an ASR of 27.0 per 100,000 and approximately 29,000 new cases annually. The male ASR stands at 38.4, while the female ASR is 16.9.

Like Japan, South Korea’s diet includes a large quantity of fermented and salted foods, such as kimchi, soybean paste, and pickled seafood. While these are culturally significant and offer nutritional benefits, their high salt content increases the risk of gastric mucosal injury and cancer development.

The nation also deals with a high burden of H. pylori infection, despite recent declines due to improved sanitation and antibiotic use. Additionally, South Korea’s intensive national screening programme, launched in 1999, targets adults aged 40 and above for biennial upper endoscopy or radiographic exams.

This widespread screening has improved early detection and survival but also reveals more asymptomatic and early-stage cases, contributing to the overall higher incidence rate. However, unlike some countries, South Korea has a robust universal healthcare system, ensuring greater access to cancer services.

Iran shares the fourth position globally, with an ASR of 19.4 per 100,000. The burden is greater in certain provinces, especially in northern and northwestern Iran, where gastric cancer is a leading cause of cancer mortality.

Several factors contribute to Iran’s high stomach cancer rates. The population consumes salted and smoked foods, especially in rural areas where food preservation is often necessary due to limited refrigeration. There is also inadequate intake of fresh fruits and vegetables, which lowers antioxidant protection against oxidative stress in the gastric lining.

Iran exhibits high rates of H. pylori infection, often acquired during early childhood and left untreated due to variable healthcare access. The infection prevalence remains over 80 percent in some regions. While Iran has made progress in cancer awareness, screening and early detection services remain patchy, especially outside urban areas.

Environmental factors, such as nitrate-rich drinking water and potential exposure to carcinogenic compounds in some regions, may further aggravate risks. Despite progress in public health, the healthcare infrastructure struggles to keep up with the rising burden.

Tajikistan, a Central Asian country with limited healthcare infrastructure, also reports an ASR of 19.4 per 100,000. Like Iran, it faces high stomach cancer incidence due to a combination of dietary habits, infection burden, and healthcare inaccessibility.

The population frequently consumes preserved foods, dried meat, and salted dishes, especially in rural households. Fresh produce availability is inconsistent, particularly during winter months.

As with other countries in the region, H. pylori infection is widespread due to poor sanitation, lack of screening, and low awareness. In many rural settings, people do not seek medical help until symptoms become severe, which leads to late-stage diagnosis and higher mortality.

Socioeconomic limitations further compound the issue. Healthcare access remains limited, especially for diagnostic procedures like endoscopy. In some areas, there may also be environmental carcinogen exposure, but data remains limited. Collectively, these factors maintain Tajikistan’s place among the highest-risk nations.

Common Risk Factors Among These Countries

• Helicobacter pylori infection remains the single most consistent risk factor. It causes chronic gastritis and is responsible for the majority of non-cardia gastric cancers. Countries with high infection rates report higher cancer burdens.

• High-salt diets, often including smoked or fermented foods, damage the stomach lining and support H. pylori colonisation. These foods remain culturally embedded in all five nations.

• Lack of access to screening, particularly in Iran, Mongolia, and Tajikistan, results in diagnosis at advanced stages. In contrast, Japan and South Korea detect more early-stage cancers, explaining their high but better-managed incidence.

• Older populations and male sex are additional biological risk factors. Men develop stomach cancer nearly twice as often as women, and ageing increases vulnerability.

• Environmental exposures, such as nitrates in drinking water or workplace toxins, may play a role in specific regional hotspots, particularly in parts of Iran and Tajikistan.

Global Contrast

By comparison, countries in North America, Northern Europe, and parts of sub-Saharan Africa report significantly lower stomach cancer rates — typically under 3 per 100,000 population. These regions benefit from:

• Low H. pylori prevalence

• Better sanitation

• Balanced diets with fewer preserved foods

• Robust early detection and public health infrastructure

References

1. World Cancer Research Fund. “Stomach Cancer Statistics.” 2022. https://www.wcrf.org/preventing-cancer/cancer-statistics/stomach-cancer-statistics/

2. American Cancer Society. Global Cancer Facts & Figures 5th Edition. Atlanta: American Cancer Society, 2024.

3. World Population Review. “Stomach Cancer Rates by Country.” Accessed July 2025. https://worldpopulationreview.com/country-rankings/stomach-cancer-rates-by-country

4. Sung, Hyuna et al. “Global Cancer Statistics 2024.” CA: A Cancer Journal for Clinicians. https://doi.org/10.3322/caac.21834

5. Bagheri, M., et al. “Epidemiology of Stomach Cancer in Iran.” Middle East Journal of Cancer 2023.

(Rh/DJR/MSM/SE)