Table 1. National Comprehensive Cancer Network (NCCN) group 1 and group 2 lung cancer screening criteria.

Variable	NCCN group 1 (n=1,105)	NCCN group 2 (n=356)
Age	55–74	50–74*
Smoking history	≥30 pack years	≥20 pack years
Smoking status	Current or former	Current or former
Quit duration	<15 years	Any time
Additional risk factors	None required	At least one of the following required: (I) family history of lung cancer (parent, sibling, or child); (II) personal history of chronic lung disease; (III) occupational exposure to known lung carcinogen(s)**; (IV) personal history of smoking related cancer (excluding skin cancer and metastatic disease)

*, >50 in NCCN Guidelines^®; **, carcinogens include arsenic, asbestos, beryllium, cadmium, soot, chromium, diesel fumes, nickel, silica, coal smoke, and radon (occupational or documented residential).