Why Japan, Mongolia, and Iran Lead the World in Stomach Cancer Rates

5 countries have some of the world’s highest stomach cancer rates. Experts explain the mix of diet, genetics, and access shaping this crisis.

Published on 23 Jul 2025, 09:39 AM IST

At Tokyo’s National Cancer Center Hospital, Dr. Hiroshi Tanaka peers over a set of charts showing a trend few want to see: stomach cancer remains stubbornly prevalent in Japan, where the age-standardized rate hit 27.6 per 100,000 in 2022. With more than 126,000 new cases diagnosed annually, Japan continues to rank among the highest globally in gastric cancer incidence.

But it’s not alone.

According to the Global Cancer Observatory (GLOBOCAN), the top five countries with the highest rates of stomach cancer are:

  1. Mongolia

  2. Japan

  3. South Korea

  4. Iran

  5. Tajikistan

Each of these nations tells a unique — and alarming — story.


🔍 The Data Behind the Diagnosis

In Mongolia, the incidence rate is a staggering 32.5 per 100,000, the highest in the world. In Japan and South Korea, public health officials have long known that dietary factors — salt-preserved foods, pickled vegetables, and smoked meats — contribute significantly. Iran and Tajikistan, meanwhile, grapple with a blend of limited healthcare access, genetic predispositions, and chronic Helicobacter pylori infection, a major known risk factor for stomach cancer.

“In Mongolia, we’re seeing late-stage diagnoses far too often,” says Dr. Oyun-Erdene Batsukh, a leading oncologist based in Ulaanbaatar. “By the time patients arrive, it's often too advanced for surgery.”


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📣 What Experts and Citizens Are Saying

In Busan, South Korea, where rates of gastric cancer are still among the highest in the developed world, citizen awareness campaigns have been stepped up.

“We started routine endoscopic screenings at age 40,” says Dr. Kim Hyun-soo, a preventive medicine specialist. “This has improved early detection rates significantly — but we still face cultural resistance among older men who avoid hospitals.”

Iranian medical researcher Dr. Shirin Abbaszadeh explains a different challenge: “In rural areas, spicy and salty foods are part of heritage. Changing that isn’t just medical — it’s social.”

A Reddit thread titled “Why is stomach cancer still so common in Japan?” recently gained traction. “I’m 27 and already had my first scope,” one user wrote. “It’s just something we do here — like a rite of passage.”


🧬 Why These 5 Countries?

Here’s a closer breakdown:

🇲🇳 Mongolia

  • Diet heavy in salt-preserved meats

  • Low rates of early screening

  • High levels of H. pylori infection

  • Limited rural healthcare infrastructure

🇯🇵 Japan

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  • High life expectancy, thus more cancer detection

  • Diet rich in pickled, smoked foods

  • Strong early screening programs (yet still high incidence)

  • Genetic risk factors among certain populations

🇰🇷 South Korea

  • Similar dietary risks to Japan

  • Government-mandated biennial gastric screenings

  • High public awareness but rising concerns about young cases

🇮🇷 Iran

  • Regional disparities in healthcare

  • Cultural food habits

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    Low access to antibiotics for H. pylori eradication in rural areas

🇹🇯 Tajikistan

  • Weak national cancer registry

  • Low public awareness

  • Poor nutrition and healthcare post-Soviet breakup


🩺 The Bigger Picture: Global Gaps in Prevention

Compared to Western Europe, the U.S., or Australia — where stomach cancer rates are below 7 per 100,000 — the disparity is sharp.

Dr. Aditi Sharma, an epidemiologist with WHO, puts it plainly: “In wealthier countries, early eradication of H. pylori, better refrigeration of food, and healthier diets have drastically cut rates. But this isn’t global yet.”

Countries with higher public health spending and nutrition education have significantly reduced incidence — showing it’s not just genes or fate, but policy.


📉 What Happens Next?

The World Health Organization is now pushing for:

  • Universal H. pylori screening programs

  • Reduced salt intake campaigns

  • Subsidized gastroscopy programs for at-risk populations

Japan and South Korea continue to lead with robust government health initiatives — but the race is on to apply these lessons elsewhere.

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Dr. Ambrose Greenfelder

Senior Editor & Content Strategist

Dr. Ambrose Greenfelder is a highly skilled and detail-oriented Senior Editor with over a decade of experience in digital journalism, editorial strategy, and content curation. He leads the editorial team at HeyColleagues.com, ensuring every article meets the highest standards of accuracy, clarity, SEO best practices, and journalistic integrity. With a background in media studies and a doctorate in communication, Dr. Greenfelder specializes in shaping compelling narratives, mentoring writers, and aligning content with reader interests and search trends. His editorial vision plays a crucial role in keeping the website informative, trustworthy, and engaging for a global audience.

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