Smoking and lung cancer.

Nowadays, around one-third of adults are known to be smokers, and smoking rates are increasing among the female population. It is estimated that deaths attributable to tobacco use will rise to 10 million by 2025, and one-third of all adult deaths are expected to be related to cigarette smoking. The association between cigarettes and lung cancer has been proven by large cohort studies. Tobacco use has been reported to be the main cause of 90% of male and 79% of female lung cancers. 90% of deaths from lung cancer are estimated to be due to smoking. The risk of lung cancer development is 20-40 times higher in lifelong smokers compared to non-smokers. Environmental cigarette smoke exposure and different types of smoking have been shown to cause pulmonary carcinoma. DNA adducts, the metabolites of smoke carcinogens bound covalently with DNA, are regarded as an indicator of cancer risk in smokers. In recent decades, there has been a shift from squamous and small cell lung cancer types to adenocarcinoma, due to increasing rates of smoking among female population and rising light cigarette usage. After smoking cessation, the cumulative death risk from lung cancer decreases. Patients who continue smoking experience greater difficulties during cancer treatment. Stopping smoking may prolong survival in cancer patients, and also decreases the risk of recurrent pulmonary carcinoma. In order to save lives and prevent smoking related hazards, physicians should advise both healthy individuals and those with cancer of the benefits of stopping smoking.