35-40% of adults 35 and older will have nodules in their lungs. Pulmonary nodules are defined as 3cm and less in maximal dimension.   This guidance applies to incidentally discovered nodules. It does not apply to patient with known cancer or immunocompromised patient.

Notes:

Original Article

Definition of nodule growth： If a nodule has increased in size by 1.5mm since the previous study. Further treatment is necessary.