How Long Does it Take for H. Pylori to Cause Cancer?

The gastrointestinal tract is one of the most significant and extensive systems in the body; beginning from the mouth, the GIT comprises the esophagus, stomach, intestines, and colon. The stomach is often home to bacteria that cause infections and ulcers, possibly leading to cancer. While most tumors, cysts, or cancers do not result from bacterial infections, H. pylori is among the few culprits. So, how long does it take for H. pylori to cause cancer? This article tells you how long does it take for H. pylori to cause cancer and how to prevent it.

But before we talk about how long does it take for untreated H. pylori to cause cancer, understanding H. pylori and its effects is important.

What is H. Pylori?

Helicobacter pylori or H. pylori is a type of stomach bacteria that causes stomach and duodenal ulcers. The infection is common in children and adults who have ingested contaminated food or water. It resides in the stomach’s mucosal lining, which protects it from the immune system and stomach acids. H. pylori also interferes with local immune responses, making them ineffective.

Before discovering H. pylori, researchers believed spicy food caused ulcers. However, Dr. Robin Warren, a pathologist in Australia, observed a small bacteria in patients. On further investigation, Dr. Warren and Dr. Marshall found the same bacteria in over 100 patients with gastric inflammation and ulcers. To be sure, Dr. Marshall drank an H. pylori-infused broth; he eventually got the same symptoms.

H. pylori infection is not typically deadly, and around 67% of people globally have it; most infected individuals do not even develop ulcers.

A blood test or fecal exam can detect the presence of H. pylori in your stomach. If detected, your doctor will prescribe you antibiotics to eliminate Helicobacter pylori.

Does H. Pylori Cause Cancer?

After discovering H. pylori, researchers began considering the bacteria’s connection with stomach cancer. The analysis of 12 H. pylori and stomach cancer cases from the 1990s showed a higher incidence in infected individuals.

WHO classified H. pylori as a human carcinogen in 1994 because of its role in causing stomach cancer. Later, the National Toxicology Program’s 15th Report on Carcinogens in 2021 also mentioned H. pylori on the list of substances that cause cancer in humans.

Studies show that the inflammation of the stomach lining because of H. pylori may cause cancer. Some strains of H. pylori with CagA inject it into the junctions of the stomach lining. It improves cell motility and disrupts cell growth. Furthermore, research found that people infected with the bacteria are at a higher risk of non-cardia gastric cancer. CagA-positive strains have been seen to cause gastric cancer more often than CagA-negative strains.

At the same time, bacteria in the stomach lining may give rise to lymphoid tissue; it can become mucosa-associated lymphoid tissue (MALT) lymphoma. Like non-cardia gastric cancer, people infected with H. pylori are at a higher risk for MALT lymphoma as well.

Thus, untreated H. pylori can eventually lead to two types of cancers:

• Non-cardia gastric cancer affecting the stomach, not near the esophagus
• MALT lymphoma that develops out of lymph nodes in the stomach lining

How Long Does it Take for H. Pylori to Cause Cancer?

Research shows that the risk of developing gastric cancer is 0.30% per year.

As studies suggested that treating H. pylori reduced the risk of developing gastric cancer, follow-up research shared further insights. The study was conducted on 1674 patients who received treatment against H. pylori. The patients had gone through endoscopy to look for infection and peptic ulcers. After the treatment, the patients underwent a yearly endoscopy for 14 years.

Reports showed the incidence of gastric cancer in 28 out of the 1674 patients until 13.7 years post-treatment. Thus, the risk of developing gastric cancer was 0.30% per year. 16 of the gastric cancers were intestinal type, while 12 were diffuse type. The yearly risk for each cancer was 0.17% and 0.13% respectively.

Failure to treat H. pylori infection can lead to cancer, but the risks do not subside completely even after treatment. So, despite low occurrence, you must go for regular follow-up to avoid gastric cancer because of H. pylori.

Occurrence of Cancer Due to H. Pylori in the US

Gastric cancer is the fifth most common cancer in the world and the fourth deadliest, resulting in over 700,000 deaths in 2020.

In the US, 1.4% of diagnosed cancers are gastric, mainly affecting ethnic and racial minority groups. The United States of America has seen an increase in the incidence of non-cardia gastric cancer. At the same time, gastric cardia cancer cases are rising globally.

Furthermore, gastric MALT lymphoma occurs in one of every 100,000 people and 2% to 8% of all stomach cancer cases.

Risk Factors for Stomach Cancer Sue to H. Pylori

When we talk about how long it takes for H. pylori to cause cancer, it is important to mention that it is a rare occurrence. Most gastric cancer does not develop due to H. pylori.

Surveys show that only one to three out of a hundred people infected with H. pylori develop stomach cancer.

Though the chances of stomach cancer because of H. pylori are quite low, some factors may contribute to higher risks. Some researchers believe that the type of the bacteria might be a defining factor. Other risk factors for stomach cancer include:

• Smoking
• Alcohol intake (3 or more drinks daily)
• Processed meat and a high intake of salt
• Food stored in unsanitary conditions
• Obesity due to excess body fat
• Cancer history in the family

How to Prevent Gastric Cancer from H. Pylori?

While the big question is how long does it take for H. pylori to cause cancer, prevention is primary. Individuals with symptoms of H. pylori infections must get themselves tested and treated to prevent ulcers and cancer. Common symptoms of H. pylori include indigestion, bloating, abdominal pain, discomfort in the chest, and the urge to burp.

A randomized clinical trial in Shandong, China, showed that two weeks of antibiotic treatment against H. pylori reduced gastric cancer incidence by 50% over 22 years of follow-up after treatment.

Another trial showed that patients undergoing surgery for early gastric cancer who received antibiotic treatment against H. pylori are 50% less likely to develop gastric lesions.

Does H. Pylori Prevent Cancer?

Now that you know how long for H. pylori to cause cancer, there’s something else that might surprise you!

Besides being a culprit behind MALT lymphoma and non-cardia gastric cancer, H. pylori is seen to also contribute to a lowered risk for certain cancers like:

• Cardia gastric cancer of the upper stomach
• Esophageal adenocarcinoma associated with gastroesophageal reflux disease and Barrett’s esophagus

Decades of H. pylori colonization neutralizes stomach acidity and reduces acid reflux to the esophagus. As acid reflux is a major risk factor for esophageal cancer, H. pylori indirectly decreases the chances of the cancer.

The Bottom Line

H. pylori is a common stomach bacteria that leads to ulcers in the stomach and duodenum. It can be treated with antibiotics to prevent further complications. Studies have shown that untreated H. pylori infection may lead to stomach cancer. Thus, people wonder, how long does it take for H. pylori to cause cancer. Research shows that the risk of developing gastric cancer is 0.30% per year. In a survey conducted among 1674 patients after H. pylori treatment, 28 developed stomach cancer in 13 years. Though the incidence of cancer is quite low, you must get yourself evaluated regularly to catch the disease in time.

FAQs

When does H. Pylori turn into cancer?

While H. pylori is a common stomach bacteria, leaving it untreated can lead to stomach cancer. So, if you ask how long does it take for H. pylori to cause cancer, the long-term presence of the bacteria in the mucosal lining may lead to MALT lymphoma that develops out of lymph nodes in the stomach lining.

Does treating H. Pylori reduce cancer risk?

2 weeks of antibiotic treatment against H. pylori reduced gastric cancer incidence by 50% over 22 years of follow-up after treatment. So, treating the bacteria in time can help prevent cancer.

Can you live a healthy life with H. Pylori?

H. pylori does not go away on its own until treated, and many people spend their lives with the bacteria; some also have asymptomatic infections. However, not treating the bacteria in time can lead to symptoms like vomiting, indigestion, and severe chronic atrophic gastritis or SCAG.