Certain untreated infections can significantly increase the risk of developing cancer, according to TV doctor Dr Xand van Tulleken. Appearing on BBC Morning Live, he investigated the link between common pathogens and cancer, reassuring viewers that cancer itself is not contagious.
The discussion follows reports that one in eight cancer cases are caused by infections that thousands of people get every year. Dr Xand said the claims come from a World Health Organisation document and do discuss the possible association between developing an infection and cancer.
Study links 12% of cancer cases to infections
This discussion aligns with a study published in The Lancet Oncology. The research revealed that roughly 12% of all new cancer cases worldwide are tied directly to infections, with 2.3 million cases caused by infections in 2024.
Dr Xand said: "You cannot 'catch' cancer from people who already have cancer. Cancer is already such a stigmatised illness... you are at no risk to give [someone with cancer] a hug."
Infections compared to cigarettes
He stressed that certain infections "will not always give you cancer", but they may "increase your risk". He likened it to cigarettes - they do not directly cause cancer, but do increase the risk of developing it.
As an example, he cited HPV (a common sexually transmitted infection) that is "strongly associated" with cervical cancer. If left untreated, it can damage the DNA of cervical cells and stop them from dying normally. Dr Xand claims this risk has been minimised through years of research that led to the development of a vaccine. Millions of women have been protected, with "almost 90%" of cervical cancer cases falling in the vaccinated population.
Common infections linked to cancer
Dr Xand claims the "most common" infection linked to cancer is H Pylori. People may have been tested for it if they have ever had a stomach ulcer or gastritis. The constant "damage and repair" cycle that stomach ulcers cause could put people at greater risk of developing cancer. Hepatitis B and C were also listed as infections with known links to cancer, as was the Epstein-Barr virus, commonly linked to glandular fever.
He said: "These bugs are very common. It is interesting that they are associated with cancer, in terms of public health, but it shouldn't change your everyday behaviour."
Key pathogens and prevention
The report lists key pathogens responsible for infection-linked cancers: Helicobacter pylori (H. pylori) for ~760,000 cases (about 4% of global cancers), primarily stomach cancer; Human Papillomavirus (HPV) for ~750,000 cases (about 4%), primarily cervical, anal, and head/neck cancers; Hepatitis B Virus (HBV) for ~360,000 cases (about 2%), primarily liver cancer; Epstein-Barr Virus (EBV) for ~260,000 cases (about 1%), linked to nasopharyngeal, gastric, and Hodgkin lymphoma; and Hepatitis C Virus (HCV) for under 1% of cases, primarily liver cancer.
Many of these cancers are preventable through vaccination (such as the HPV and Hepatitis B vaccines) or antibiotic and antiviral treatments (such as curing H. pylori or hepatitis C). However, about 75% of these infection-linked cases occur in low- and middle-income countries due to limited access to screening and vaccines. Regular tests (such as cervical screenings) can catch precancerous changes early.
