A common bacteria found in the stomach could be fuelling millions of stomach cancer cases globally. A new study suggests this bacterial infection could cause nearly 12 million cancers among people born over a single decade.Scientists from the International Agency for Research on Cancer (IARC), part of the World Health Organisation, project that if current trends continue, around 15.6 million people born between 2008 and 2017 will be diagnosed with stomach (gastric) cancer in their lifetime. Of all those cases – 76%, i.e., a staggering 11.9 million, may be caused by the Helicobacter pylori bacteria (H. pylori), according to a study published in the journal Nature Medicine.Read on to know more.
What is H. pylori?
Stomach cancer, often called a “silent killer,” is grabbing global attention following the striking new warning – thanks to the world’s most under-the-radar risk.
Helicobacter pylori, previously known as Campylobacter pylori, is a gram-negative, flagellated, helical bacterium. Mutants can have a rod or curved rod shape that exhibits less virulence. This easily transmissible bacterium often shows no symptoms – which makes it more invincible.Let’s explore more.A common but concealed inhabitant: Half the world’s population hosts H. pylori in their stomach lining, often without visible symptoms. It’s classified as a class I carcinogen by IARC and the US Carcinogens Report.Transmission vectors: The bacterium spreads through contaminated food or water and close contact, like saliva or fecal-oral routes. It’s more prevalent in regions with poor sanitation and crowded living conditions, especially in Asia, Africa, and parts of Latin America.Silent but damaging: Though only 10–20% may show mild symptoms like indigestion or bloating, H. pylori quietly triggers chronic inflammation – setting the stage for ulcers, atrophic gastritis, and eventually cancer.
What does the study underline?
For the study, scientists examined the incidence of stomach cancer in 185 countries in 2022 and combined it with projections of future deaths.They looked at the potential impact of screen-and-treat strategies for H. pylori and found the number of stomach cancers could be cut by up to 75% overall.Asia accounts for two-thirds of projected future cases, with 10.6 million cases (68% of the total), followed by the Americas (2 million or 13%), Africa (1.7 million or 11%), Europe (1.2 million or 8%), and Oceania (0.07 million or 0.4%).The study projected that under current trends, 11.9 million people could be diagnosed with stomach cancer attributable to H. pylori infection by 2101, which is the year someone born in 2017 would turn 84.Dr. Jin Young Park, one of the study’s co-authors and head of the gastric cancer prevention team at the WHO’s International Agency for Research on Cancer (IARC), said: “It is essential that health authorities make gastric cancer prevention a priority and accelerate efforts to control it by planning pilot and feasibility projects, including H. pylori screen-and-treat programmes,” adding, “With demographic changes set to increase the gastric cancer burden in many parts of the world, there is an urgent need for coordinated prevention strategies and for regional health systems to be prepared to manage the growing burden.”
H. pylori and stomach cancer: A deadly connection
Stomach cancer is largely preventable, but the prognosis is poor once a patient is diagnosed. It is the fifth most common form of cancer worldwide, killing an estimated 770,000 people per year. As per the study, chronic infection with H. pylori is a major cause, and it helps explain the rise in stomach cancers among young people in recent years.The link between H. pylori and gastric adenocarcinoma is solid: infected individuals have a 2–6-fold greater risk. According to research, around 90% of stomach cancers are linked to this infection, and up to 89% of non-cardia gastric cancers may be due to H. pylori. Its presence is also tied to MALT lymphoma, with tumor regression observed after eradication.But how does a bug become a carcinogen?The bacterium’s virulence, especially strains containing the cagA gene and the cag pathogenicity island, intensifies inflammation and damages DNA repair mechanisms. Persistent inflammation produces reactive oxygen and nitrogen species, leading to DNA damage in gastric cells.Genetic susceptibility and co-factors: Not all infected individuals develop cancer. A study showed that certain genetic variants prompt immune-suppressive environments via IFNα, increasing cancer risk. Environmental risk factors – smoking, high salt intake, low fruit/vegetable diets, obesity, and genetic predispositions – can aggravate the damage.
What is stomach cancer?
Gastric cancer, also known as stomach cancer, is a disease where malignant (cancerous) cells form in the lining of the stomach. It’s a growth of cells that starts in the stomach, a muscular, sac-like organ in the upper abdomen that plays a key role in digesting food. Most stomach cancers are adenocarcinomas, which develop from the gland cells in the stomach’s inner lining.
While stomach cancer rates have declined in many parts of the world, it’s still a significant health concern, particularly in East Asia.Symptoms: Early-stage stomach cancer often doesn’t cause noticeable symptoms, but later stages can include pain or discomfort in the upper abdomen, heartburn, feeling full after small meals, nausea, vomiting, and weight loss.Risk Factors: Risk factors include Helicobacter pylori infection, diet (especially high salt and smoked/preserved foods), obesity, smoking, and family history of stomach cancer.
Preventing the invisible threat
Screen-and-treat programs: The study highlights that national initiatives to screen for and eradicate H. pylori could reduce new stomach cancer cases by up to 75%. Eradication has already reduced gastric cancer risk by roughly 75% in treated populations.Effective treatment protocols: Current treatment involves two weeks of quadruple therapy: two antibiotics, a PPI, plus possibly bismuth. However, rising antibiotic resistance often requires multiple courses.Early detection boosts survival: In the US, early cancer diagnosis rates rose by 53% (2004–2021), improving survival to around 75% – compared to just 7% for late-stage detection. In regions with high H. pylori prevalence, targeted screening via endoscopy and breath/stool tests starting from age 40–50 is recommended.