This is a randomized phase II trial investigating different smoking cessation methods in study subjects undergoing lung cancer screening with low-dose CT (LDCT). The study also evaluates feasibility and outcomes of LDCT screening and potential biomarkers and AI-based evaluation on CT-scans. The study subjects fulfilling I/E-criteria are randomized in 1:1 fashion to yearly LDCT for two rounds with standard smoking cessation (control) or same LDCT approach combined to mobile application based smoking cessation (intervention).

Inclusion Criteria:

• Able to provide written informed consent
• Age between 50-74
• Smoked ≥ 15 cigarettes/day for ≥ 25 years or smoked ≥ 10 cigarettes/day for ≥ 30 years and are active smokers (smoking during the last two weeks)
• Access to a smartphone (iPhone or Android)

Exclusion Criteria:

• A moderate or bad self-reported health; e.g. unable to climb two flights of stairs
• Body weight ≥ 140 kilogram
• Current or past melanoma, lung, renal or breast cancer
• A chest CT examination less than one year before inclusion
• Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial
• Subject is unwilling or unable to comply with treatment and trial instructions
• Any condition that study investigators consider an impediment to safe trial participation

National legislation does not make it possible to share clinical data.