The NLST confirmed diagnoses of lung cancer through medical record abstraction (MRA) of participants suspected by the trial to have lung cancer. MRA was triggered by:
- a self-report of lung cancer on a study update form (annual for LSS, semi-annual for ACRIN)
- positive CT or X-ray screening exam
- death certificate indicating lung cancer
- a relative informing screening center of participant's cancer (this was infrequent)
- suspicion of non-lung cancer that was determined (by MRA) to be lung cancer (e.g. metastasis to brain from a lung primary)
Note that if the MRA process did not find records indicating a lung cancer diagnosis, the lung cancer was not considered confirmed, even if a source such as a death certificate indicated lung cancer.
Data collection was pursued for all lung cancers diagnosed at any time during NLST. This included additional primary lung cancers diagnosed after the first, not just the first lung cancer per participant. The focus of data collection was on characteristics of the cancer at the time of diagnosis.
Cancer stage was originally classified according to the AJCC 6 manual, but AJCC 7 stage data are also available from a re-review of medical records after study closeout.
The Participant dataset contains sufficient information on lung cancer diagnosis to be useful for many purposes. Additional information is available in a separate Lung Cancer dataset, which contains one record per primary lung cancer.