What cancers can occur even if you don't drink or smoke?

When cancer occurs in a person even though they have never drunk a drop of alcohol or smoked a cigarette, there is incomprehension. Especially when it comes to cancers that are linked to these two main risk factors. Lung cancer, for example. Many think that only smokers develop lung cancer, but neurologists meeting at the 26th Congress of the French-Language Pneumology Society in 2022 recalled that the proportion of non-smokers developing lung cancer is 12.6%.

“This cancer affects a majority of smokers or ex-smokers (85% of cases) but people who have never smoked can also develop lung cancer. Other factors such as exposure to occupational carcinogens ( asbestos, radon, arsenic, chromium, nickel) can play a role” comments Professor Nicolas Girard, head of the medical oncology department at the Institut Curie, for us. Lung cancer may also be linked to “prolonged exposures to high levels of air pollution, particularly fine particles and gas pollutants.” Without forgetting passive smoking. “This type of lung cancer, not linked to smoking or occupational substances, is often diagnosed late, continues the specialist.

It is also often thought that only excessive alcohol drinkers are affected by liver cancer. “Certainly, chronic alcoholism is a major risk factor, but other causes, such as hepatitis B or C virus infection, non-alcohol-related cirrhosis, and genetic factors, can also cause liver cancer. reminds us of Professor Girard. It can be asymptomatic at an early stage, highlighting the importance of regular screenings in those at risk.

Head and neck cancers can also occur in people who have never drunk or smoked. Papillomavirus (or HPV) infection, particularly types 16 and 18, is associated with an increased risk of oropharyngeal cancer, and this is too often forgotten. “Human papillomavirus infection is associated with a specific type of ENT cancer called ENT squamous cell carcinoma. This type of cancer can affect different parts of the head and neck, including the mouth, throat, tonsils and the basis of the language.” HPV vaccination can play a key role in preventing infections, including those associated with head and neck cancers. It is recommended during adolescence but can also be beneficial for adults.

Public Health France reminds us: “For a certain number of cancers, the risk factors are still in the domain of research.” The obvious causes are not always proven. “There is an element of bad luck in the occurrence of cancer, explained Gianluca Severi from the Center for Research in Epidemiology and Population Health (Inserm, Villejuif) in 2019. Some individuals who have not been exposed to risk factors and who have a healthy lifestyle will nevertheless develop cancer. Why then?

“This disease results from a succession of events: mutations, but also abnormalities of the immune system which do not destroy the abnormal cells. These events result from genetic factors, intrinsic factors but also largely from external factors. would like to remind the researcher for whom cancer is not linked to chance. “Literature data allows us to estimate that up to 40% of cancers are preventable, for example by improving one's lifestyle. Starting with stopping smoking which would reduce a third of cancers.” Tobacco consumption causes 68,000 new cancers per year in France and is involved in the development of 17 different cancer sites. Alcohol is responsible for 28,000 new cases of cancer per year and 16,000 deaths.