Preventing cancer is usually linked to avoiding tobacco and alcohol, maintaining a healthy weight, eating a balanced diet and staying physically active. But there's one more factor; infections. It is another important factor that may influence cancer risk. A recent analysis published in The Lancet Oncology estimated that around 2.3 million new cancer cases worldwide in 2024, or about 12% of all cases, were linked to infections. This means nearly one in eight cancer cases was associated with an infection.

The analysis found that five infections, Helicobacter pylori (H. pylori), human papillomavirus (HPV), hepatitis B virus (HBV), Epstein-Barr virus (EBV) and hepatitis C virus (HCV), accounted for almost all infection-related cancer cases. However, the findings do not mean that every infection can cause cancer or that everyone who gets one of these infections will develop the disease. The risk is mostly linked to infections that are present in the body for years and cause chronic inflammation, tissue damage or changes in cells. In India, around 1.9 lakh cancer cases were attributable to viral and bacterial infections.

Dr Kasturi Baruah, Cancer Physician, M|O|C Cancer Care, highlights why preventing, detecting and treating certain infections can be an important part of cancer prevention, along with established measures such as avoiding tobacco and limiting alcohol.

How Can Infections Increase Cancer Risk?

Certain infections can affect the body over a long period. When an infection becomes chronic, it may cause repeated inflammation or damage to cells and tissues. Over the years, these changes can increase the possibility of abnormal cells developing and eventually becoming cancerous. However, infection alone does not mean cancer is avoidable. The type of infection, how long it remains in the body, immune response and other lifestyle or genetic factors can all influence cancer risk.

HPV And Cervical Cancer

HPV is one of the most important infections linked to cancer. "Persistent infection with high-risk HPV types is responsible for virtually all cervical cancers and is also associated with some cancers of the anus, penis, vulva, vagina and throat," said Dr Baruah.

The good news is that HPV-related cancers are preventable. Dr Baruah added, "HPV vaccination and cervical screening can therefore play an important role in prevention."

H. Pylori Can Affect The Stomach

Helicobacter pylori, or H. pylori, is a bacterium that can infect the stomach. It can cause long-term inflammation of the stomach lining and is strongly associated with stomach cancer.

"H. pylori is another important concern. This bacterium can cause chronic inflammation of the stomach and increases the risk of stomach cancer," said Dr Baruah.

According to the analysis, H. pylori was linked to around 7,60,000 cancer cases globally in 2024, making it the largest contributor among the infection-related causes studied. The analysis attributed approximately 47,000 Indian cancer cases to H. pylori.

Hepatitis Viruses Can Raise Liver Cancer Risk

"Hepatitis B and hepatitis C viruses provide another example. Chronic infection can damage the liver over many years and increase the risk of liver cancer," said Dr Baruah.

Hepatitis B can be prevented through vaccination. Both hepatitis B and hepatitis C can also be detected through blood tests. While there is currently no vaccine for hepatitis C, effective antiviral medicines can cure most HCV infections.

What Can Be Done To Reduce The Risk?

Preventing or managing certain infections can therefore become part of cancer-prevention strategy. Some of the ways to prevent cancer include:

  • Get recommended vaccinations: HPV and hepatitis B vaccination can help prevent infections linked to certain cancers.
  • Do not skip cervical screening: Screening can identify abnormal cervical changes early, when they can be managed before becoming cancer.
  • Get infections tested: People at risk of hepatitis or other persistent infections should discuss appropriate testing with a doctor.
  • Follow safe injection and blood practices: Using sterile needles and ensuring safe blood transfusion practices can reduce transmission of blood-borne infections.
  • Practise safe sex: Appropriate sexual-health precautions can reduce the risk of infections such as HPV and hepatitis B.
  • Treat persistent infections: Infections such as H. pylori may require medical evaluation and treatment rather than being ignored.
  • Cancer-prevention measures: Avoiding tobacco, limiting alcohol, maintaining a healthy weight, exercising regularly and following a balanced diet are important measures.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.