SUMMIT is a Prospective cohort study involving patients who smoke and  used to smoke in the past 20 years. This study will examine ways to detect lung cancer before there are any symptoms, when treatment can be simpler and more successful. At present, the best way of finding lung cancer early is by a low dose computed tomography (LDCT) scan. This study is also developing a blood test that can be used either instead of LDCT to find lung cancer, or together with LDCT to improve its accuracy.

Site selection:
There are three different types of sites in this study:

1. GP Surgery where data extraction occurs; data on potential participants will be extracted from approximately 600 GP practices in London and surrounding areas.

2. Type 1 sites: UCLH, Mile End, Finchley Memorial Hospital and King George Hospital. These sites will undertake the following activities;
  a. Assess eligibility, consent and enrol participants
  b. Collect required clinical data and enter electronically onto database
  c. Collect blood samples and dispatch appropriately
  d. Undertake LDCT scanning (a CT machine will be installed into four sites)

3. Type 2 sites:
The type 2 sites are a group of hospitals within the locality which will receive referrals from the type 1 sites for diagnostic work-up within the NHS following an abnormal LDCT (for suspected lung and other cancers). Sites will use their usual cancer diagnostic pathway including treatment according to local best practice and guidelines. These sites will be required to collect outcome data such as final diagnosis, outcome of investigations and treatment plan on those referred for diagnostic work-up.

Participants will be asked to attend study visits for approximately 2.5 years from enrolment. Following the baseline study visit, most participants will return at approximately 12 and 24 months, with some participants attending more frequently for nodule management. Data will be collected via national registries and medical records, up to ten years from the date that the last participant is enrolled.

Inclusion criteria:
1. Individuals 55 to 77 years old at the time of GP data extraction, who meet either of the following criteria:

a. USPSTF LDCT screening criteria: a history of at least 30 pack years of smoking and if a former smoker, have quit in the past 15 years; or
b. PLCOm2012 6-year lung cancer risk of ≥1.3%

2. Capable of providing informed consent and willing to comply with all parts of the protocol

Exclusion criteria:
1. Currently receiving treatment (e.g. chemotherapy, radiotherapy, watchful waiting) for an active cancer. If on adjuvant hormonal therapy can be included (e.g. for breast and prostate cancer)

Approximately two years