This prospective randomized multicentered clinical study aims at implementing early diagnosis of lung cancer in high-risk heavy smokers in the Italian population. The main goal of the study is to develop a nationwide lung cancer prevention screening with high quality standard, similar to that of other screening programs i.e. breast, colon and cervix ongoing in Italy. The Italian Pulmonary Screening Network (RISP) includes 18 centers, which will promote primary prevention by offering a smoking cessation program (i.e. counselling and anti-smoking cytisine-based therapy) and secondary prevention by screening volunteers with chest Low Dose Computed Tomography (LDCT). The primary objective of the study is to demonstrate the non-inferiority of a risk-based screening strategy (less intensive, every 2 years) compared to the standard annual screening, in terms of stage I/II lung cancer incidence. Furthermore, the study aims to provide evidence whether blood biomarkers screening intervals can improve the efficiency of lung cancer screening by requiring less CT examinations while retaining the ability to diagnose lung cancer at curative state.