Table 2. Natural history of GGO based on more than 100 lesions.

First author [year] (references)	Inclusion criteria			Patients	Lesions	Follow-up time (years)	With growth [n, %]
	Size	GGO proportion	Follow-up period
Hiramatsu [2008] (37)	-	Any	≥3 months	125	125	2.9a	26c [21]
Matsuguma [2013] (38)	≤2 cm	>20%	-	171	174	2.4a	41d [24]
Chang [2013] (39)	-	100%	>2 years	89	122	4.9b	12e [10]
Lee [2013] (40)	-	Any	>2 years	114	175	3.8b	46e [26]
Kobayashi [2013] (12)	≤3 cm	≥50%	≥6 months	61	108	4.2b	29e [27]

a, mean; b, median; c, growth was defined as ≥2 mm increase in whole GGO size, ≥2 mm increase in the solid component, or emerging new solid part of any size; d, growth was defined as ≥2 mm increase in whole GGO size, ≥2 mm increase in the solid component, or emerging new solid part ≥2 mm; e, growth was defined as ≥2 mm increase in whole GGO size