The present study is a randomized controlled trial of LDCT screening for lung cancer versus usual care. 6000 high-risk subjects (age 45-70) were recruited and randomized to the Active arm (Baseline + 2 biennial repeated LDCT screening) or to the Passive arm, followed up in usual care (Baseline + 2 biennial repeated questionnaire inquiries). Follow-up for lung cancer incidence, lung cancer mortality and overall mortality was performed. Blood samples were stored from the Active arm in a Biobank. Management of positive screening test was carried out by a pre-specified protocol.

Inclusion Criteria:

• Eligible participants were those aged 45-70 years, and with either of the following risk factors:

  1. history of cigarette smoking ≥ 20 pack-years, and, if former smokers, had quit within the previous 15 years;
  2. malignant tumors history in immediate family members;
  3. personal cancer history;
  4. professional exposure to carcinogens;
  5. long term exposure to second-hand smoke;
  6. long term exposure to cooking oil fumes.

Exclusion Criteria:

1. Had a CT scan of chest within last 12 months
2. History of any cancer within 5 years