The main objective is to evaluate the adherence of smoking patients to lung cancer screening by low-dose CT scan, when proposed by the general practitioner.

Lung cancer is the leading cause of cancer mortality in France and worldwide. The KBP2020 study conducted in general hospitals, including 8999 patients diagnosed with lung cancer in the year 2020, showed that 73% of lung cancer cases were diagnosed at an advanced symptomatic stage, explaining the high rate of metastatic status at diagnosis, reaching 58%. For this category of patients, 3-month mortality remains very high, close to 25%. Several large randomized studies have demonstrated that lung cancer screening with low-dose CT scans enables lung cancer to be diagnosed at an early, asymptomatic stage, when it is mostly accessible to curative surgical treatment. This early detection and subsequent treatment reduced specific mortality by 20% in the NLST study, and by up to 39% at 10 years in the MILD study. Overall mortality was reduced by 6.7% in the NLST study. This scientific evidence has led the French National Authority for Health to encourage the implementation of a pilot program, to be organized by the French National Cancer Institute.

The hypothesis of the study is that the proposal of CT screening for lung cancer will be better adhered to if it is made by the general practitioner of individuals at risk. Adherence is defined by an initial scan, followed by a second scan one year after the first, with participation in screening on an annual basis.

Given the trust that generally characterizes the relationship between patients and their GP, and the fact that intercurrent consultations provide reminders of the need for an annual check-up, the assumption is for an initial participation rate of at least 50%, and a continued participation rate of 70% at 1 year.

Communication of results by the GP will help to limit anxiety, particularly in the event of an undetermined result, which will be assessed by the anxiety section of the Hospital Anxiety and Depression scale questionnaire translated into French.

In addition, the success of smoking cessation will be compared with literature data in the context of screening. The hypothesis is that the cessation rate will be higher due to the possibility of adapting nicotine substitution by the GP and his or her repeated support in the cessation process.

Finally, knowledge of patients' histories will help to limit unnecessary explorations and to better identify for which participants screening reveals COPD (emphysema), osteoporosis or unrecognized coronary artery disease.

Inclusion Criteria :

• Adults aged 50-74
• Active smoker or weaned smoker for less than 15 years, of at least 20 pack-years
• Affiliation with a social security scheme or CMU (beneficiary or beneficiary entitled)
• Written informed consent prior to study participation

Exclusion Criteria :

• History of lung cancer
• Thoracic CT scan performed within the previous year
• 1-year follow-up not possible
• Inability to travel independently to Hôpital Cochin or Hôpital Bichat for scans
• People with severe co-morbidities contraindicating exploration and/or management of lung cancers
• People in poor general health (=PS2 and above)
• People with a history of cancer under active surveillance by thoracic computed tomography (CT and PET scans)
• People with rest dyspnea (=mMRC4)
• Recent weight loss, altered general condition or hemoptysis, raising suspicion of progressive lung cancer
• Signs of respiratory infection (fever, productive cough)
• Patients under guardianship, curatorship or protected adults
• Inability to give free written informed consent prior to study participation