Table 3.

Differences in follow-up strategies of SSN in guidelines.

Guideline	pGGN diameter				PSN diameter
	<6mm	≥6mm	<20mma/30mmb	≥20mma/30mmb	<6mm	≥6mm	<8mm	≥8mm
2022 NCCN NSCLC Guidelines	No follow-up needed	CT at 6-12 month to confirm persistence, then CT every 2 years until 5 years			No follow-up needed	CT at 3-6 month to confirm persistence; If unchanged and solid component < 6 mm, annual CT should be performed for 5 years; If the solid component ≥ 6mm, then PET-CT or surgical resection.
2017 Fleischner Society Guidelines	No follow-up needed	CT at 6-12 month to confirm persistence, then CT every 2 years until 5 years			No follow-up needed	For solid component <5mm CT at 3-6 month to confirm persistence, then annual CT until 5 years For solid component ≥5mm CT at 3-6 month to confirm persistence, PET-CT/biopsy/resection are recommended for the persistence of the nodule.
2013 ACCP Guidelines	No follow-up needed	Annual CT for at least 3 years; If diameter>10mm, early follow-up at 3 months, followed by nonsurgical biopsy and/or surgical resection for nodules that persist.					CT at 3, 12, 24 month, and then annual CT for at 1-3 years	CT at 3 month to confirm persistence; For persistent, biopsy/surgical resection; For nodule >15 mm at first CT scan, biopsy/PET-CT/surgical resection.
2016 Clinical practice consensus guidelines for Asia	Discuss the role of continued surveillance with patient	Annual CT for at least 3 years					CT at 3, 6, 12 month, and then annual CT surveillance	CT at 3 month, and consider antimicrobial therapy (nonsurgical or surgical biopsy consider PET scanning for staging before biopsy)
2022 NCCN LCS Guidelines			Annual screening LDCT until the patient is no longer a candidate for definitive treatment; For stable, annual LDCT; For growth(>1.5mm), review at 6 months	LDCT in 6 month; For stable, annual LDCT; For growth(>1.5mm), review at 6 months or consider biopsy or surgical excision	Annual screening LDCT until the patient is no longer a candidate for definitive treatment;	For solid component <6mm LDCT at 6 month to confirm unchange, then annual LDCT
						For solid component ≥6 to <8mm LDCT in 3 month or consider PET-CT; if unchanged, LDCT at 6 moth, then annual CT Low suspicion of lung cancer, LDCT in 3 month; Low suspicion of lung cancer, biopsy or resection
						For solid component >8mm Chest CT+ contrast and/or PET-CT; Low suspicion of lung cancer, LDCT in 3 month; Low suspicion of lung cancer, biopsy or resection
					Newly developed nodules LDCT in 6 month	Newly developed nodules If solid component <4mm, LDCT in 3 month; If solid component ≥4mm, Chest CT+ contrast and/or PET-CT; Low suspicion of lung cancer, LDCT in 3 month; High suspicion of lung cancer, biopsy or resection.
2019 Lung-RADSb			Continue annual screening with LDCT in 12 months.	≥ 30 mm and unchanged or slowly growing: Continue annual screening with LDCT in 12 months. ≥ 30 mm on baseline CT or new: 6 month LDCT; unchanged for ≥ 3 months, then annual screening with LDCT in 12 months.	Continue annual screening with LDCT in 12 months.	With solid component < 6 mm OR new < 6 mm total diameter: 6 month LDCT; unchanged for ≥ 3 months, then annual screening with LDCT in 12 months. With solid component ≥ 6 mm to < 8 mm OR with a new or growing < 4 mm solid component: 3 month LDCT; PET/CT may be used when there is a ≥ 8 mm solid component; Unchanged for ≥ 3 months, then annual screening with LDCT in 12 months.		a solid component ≥ 8 mm OR a new or growing ≥ 4 mm solid component: Chest CT with or without contrast, PET/CT and/or tissue sampling depending on the probability of malignancy and comorbidities; unchanged for ≥ 3 months, then annual screening with LDCT in 12 months. For new large nodules that develop on an annual repeat screening CT, a 1 month LDCT may be recommended to address potentially infectious or inflammatory conditions.

pGGN, pure ground-glass nodule; mGGN, mixed ground-glass nodule; NCCN, National Comprehensive Cancer Network; NSCLC, Non-Small Cell Lung Cancer; LCS, Lung Cancer Screening; ACCP, American College of Chest Physicians; CT, computed tomography; LDCT, low-dose computed tomography; PET-CT, Positron Emission Tomography-Computed Tomography; Lung-RADS, Lung imaging reporting and data system; ^aindicates that 2022 NCCN LCS Guidelines managed pGGN with a limit of 20mm; ^bindicates that 2019 Lung-RADS managed pGGN with a limit of 30mm.