What is the appropriate follow-up for a smoker with a new pulmonary nodule (lung nodule)?

From the Guidelines

Appropriate follow-up for a smoker with a newly discovered lung nodule should be guided by the nodule's characteristics and the patient's risk factors, with the most recent guidelines from 2025 recommending a multidisciplinary approach for nodule management 1.

Key Considerations

• For nodules 6mm or larger, follow-up CT at different time intervals, PET/CT, biopsy, or standard staging evaluation is recommended, depending on nodule size, attenuation, risk factors for lung cancer, surgical risk, and clinical probability of cancer 1.
• The Fleischner Society guidelines recommend a follow-up CT at different time intervals, PET/CT, tissue sampling, or a combination, depending on nodule size, attenuation, morphology, comorbidities, and other factors 1.
• The NCCN guidelines recommend a multidisciplinary approach for nodule management, including the specialties of thoracic radiology, pulmonary medicine, and thoracic surgery, and suggest using a CT dose index volume (CTDIvol) threshold of 3 mGy or less for a patient of average size 1.

Follow-up Intervals

• For smaller nodules (less than 6mm), serial CT surveillance is typically appropriate, with follow-up intervals based on nodule size: 6-12 months for nodules 4-6mm and 12 months for those smaller than 4mm 1.
• Risk factors that warrant more aggressive evaluation include older age, heavy smoking history, larger nodule size, irregular or spiculated margins, upper lobe location, and solid appearance 1.

Important Recommendations

• Low-dose CT without IV contrast is recommended for follow-up of lung nodules, with a CT dose index volume (CTDIvol) threshold of 3 mGy or less for a patient of average size 1.
• The use of thinner images, maximum intensity projection (MIP) or volume-rendered images, and computer-aided diagnosis (CAD) software can increase the sensitivity of small-nodule detection 1.
• Nodule risk calculators, such as the Tammemagi lung cancer risk calculator, may be helpful in identifying patients at high risk for lung cancer 1.

From the Research

Follow-up for Smoker with New Nodule

• The appropriate follow-up for a smoker with a new nodule depends on the size and type of the nodule, as well as the patient's risk factors and preferences 2, 3.
• For small solid nodules (< 8 mm), a repeat chest CT in 6 to 12 months may be recommended, depending on the presence of patient risk factors and imaging characteristics associated with lung malignancy 2.
• For larger solid nodules (≥ 8 mm), management options include surveillance imaging, positron emission tomography-CT imaging, nonsurgical biopsy with bronchoscopy or transthoracic needle biopsy, and surgical resection 2.
• Part-solid pulmonary nodules are managed according to the size of the solid component, with larger solid components associated with a higher risk of malignancy 2.
• Ground-glass pulmonary nodules have a probability of malignancy of 10% to 50% when they persist beyond 3 months and are larger than 10 mm in diameter 2.
• The incidence of new nodules is 2-3% annually, with the cancer risk increasing by nodule size 3.
• Current guidelines recommend a comprehensive approach to the management of lung nodules, including clear algorithms for imaging protocols and follow-up 4.

Nodule Size and Cancer Risk

• The probability of malignancy is less than 1% for all nodules smaller than 6 mm and 1% to 2% for nodules 6 mm to 8 mm 2.
• Lung cancer risk increases from 1.1% for nodules < 4 mm to 24.0% for those ≥ 20 mm 3.
• New solid nodules that are 4 to < 6 mm and 6 to < 8 mm have a higher cancer risk compared to solid nodules detected at baseline 3.

Patient Risk Factors and Preferences

• Patient risk factors, such as chronic obstructive pulmonary disease and coronary artery disease, should be taken into account when determining the appropriate follow-up for a smoker with a new nodule 2.
• Patient preferences should also be considered when deciding on the management of a lung nodule 2, 4.