What is the appropriate workup for a suspected nodule (module)?

Workup for a Suspected Pulmonary Nodule

The appropriate workup for a suspected pulmonary nodule should follow a size-based approach with low-dose CT surveillance as the primary method for nodules ≤8 mm, while nodules >8 mm require risk assessment and may need additional testing such as PET/CT, biopsy, or surgical resection. 1

Initial Assessment and Categorization

• Pulmonary nodules should be categorized based on size, density (solid vs. subsolid), and number (solitary vs. multiple) 1
• All CT scans should be reconstructed with thin sections (≤1.5 mm, typically 1.0 mm) to enable accurate characterization and measurement 1
• Risk assessment should include clinical factors (smoking history, age, previous malignancy) and imaging characteristics (size, morphology, location) 1

Management Algorithm for Solid Nodules

Solid Nodules <6 mm (<100 mm³):

• Low-risk patients: No routine follow-up needed 1
• High-risk patients: Optional CT at 12 months, especially for suspicious morphology or upper lobe location 1

Solid Nodules 6-8 mm (100-250 mm³):

• Low-risk patients: CT at 6-12 months, then consider CT at 18-24 months 1
• High-risk patients: CT at 6-12 months, then CT at 18-24 months 1

Solid Nodules >8 mm (>250 mm³):

• Estimate probability of malignancy using clinical judgment or validated models 1
• For low probability of malignancy (<5%): Serial low-dose CT surveillance 1
• For moderate probability (5-60%): Consider PET/CT before deciding on surgical resection or continued surveillance 1
• For high probability (>60%): Consider surgical resection; PET/CT may be used for preoperative staging rather than nodule characterization 1
• Nonsurgical biopsy should be considered when clinical probability is moderate, imaging findings are discordant with clinical assessment, or when a benign diagnosis requiring specific treatment is suspected 1

Management Algorithm for Subsolid Nodules

Pure Ground-Glass Nodules <6 mm:

• No routine follow-up required 1
• Selected high-risk patients may benefit from follow-up at 2 and 4 years 1

Pure Ground-Glass Nodules ≥6 mm:

• CT at 6-12 months to confirm persistence, then CT every 2 years until 5 years 1

Part-Solid Nodules <6 mm:

• No routine follow-up required 1

Part-Solid Nodules ≥6 mm:

• CT at 3-6 months to confirm persistence 1
• If unchanged and solid component remains <6 mm, annual CT for 5 years 1
• Persistent part-solid nodules with solid components ≥6 mm should be considered highly suspicious 1

Multiple Nodules Management

• Use the most suspicious nodule as a guide to management 1
• For multiple solid nodules with at least one ≥6 mm: Follow-up at 3-6 months, then consider CT at 18-24 months 1
• For multiple subsolid nodules <6 mm: CT at 3-6 months; if stable, consider CT at 2 and 4 years 1
• For multiple subsolid nodules ≥6 mm: CT at 3-6 months, with subsequent management based on the most suspicious nodule 1

Special Considerations

• PET/CT is recommended for solid nodules >8 mm with moderate pretest probability of malignancy (5-60%) 1
• PET/CT has limitations: false negatives can occur with small nodules (<8 mm), carcinoid tumors, and adenocarcinomas with ground-glass components 1
• Nonsurgical biopsy (bronchoscopy or transthoracic needle biopsy) has a sensitivity of 70-90% for lung cancer diagnosis 2
• When surgical biopsy is chosen, minimally invasive techniques are preferred where appropriate 1
• Patient preferences should be elicited and considered before offering management options 1

Follow-up Protocol for Indeterminate Nodules

• For nodules requiring surveillance, low-dose CT techniques should be used 1
• Follow-up intervals: 3-6 months for initial follow-up of suspicious nodules, then 9-12 months, 18-24 months, and annual follow-up thereafter based on clinical judgment 1
• For indeterminate nodules ≥10 mm, consider HRCT at 1 month (after optional antibiotic course) or immediate fine-needle aspiration for larger or more suspicious nodules 1