[Novel epidemiology in lung cancer - non-smokers, women and cannabis].

Active tobacco-smoking is the main risk factor of developing a lung cancer and the increase in smoking since the end of the sixties among French women partly explains the increase in lung cancer that has been observed in this group recently. However the part of the risk attributable to active tobacco-smoking is less in women than men and other aetiological factors need to be considered. There are some suggestions that females have a higher susceptibility to the carcinogenic effects of tobacco smoke even if the intrinsic risk of developing lung cancer is lower than in males. The incidence of lung cancer in non-smokers seems to be increasing and this may be partly due to the ageing of the general population. This incidence is variable according to continents, non-smokers with lung cancer being more frequent in Asia compared to Europe or North-America with the difference being even more pronounced in females. Histological subtype also differs according to sex and smoking habits. Adenocarcinoma is the most important histological subtype in females but also in the youngest cohorts of lung cancer patients probably linked to the modification of smoking habits (use of filters and blond tobacco). The role of cannabis as a risk factor of lung cancer is difficult to assess as most cannabis smokers are also tobacco-smokers but recent epidemiological studies suggest that cannabis is not carcinogenic.