TABLE 2.

FREQUENCY OF CT IMAGING FOR SURVEILLANCE OF SUBCENTIMETER NODULES (<8 mm)

Nodule Size	No Lung Cancer Risk Factors	Lung Cancer Risk Factors Present
≤ 4 mm	Follow-up optional*	Follow-up at 12 mo, no additional follow-up if stable
>4–6 mm	Follow-up at 12 mo, no additional follow-up if stable	Follow-up at 6–12 mo, if stable follow-up at 18–24 mo
>6–8 mm	Follow-up at 6–12 mo, if stable follow-up at 18–24 mo	Follow-up at 3–6 mo, 9–12 mo, and 24 mo if stable

Definition of abbreviation: CT = computed tomography.

^* The risk of malignancy in this category is substantially less than that in a baseline CT scan of asymptomatic smokers. If follow-up is elected then it is reasonable to do so in 12 months.