Fleischner Society Guidelines for Pulmonary Nodules Management
The 2017 Fleischner Society guidelines recommend a structured approach to pulmonary nodule management based on nodule size, characteristics, and patient risk factors, with different follow-up protocols for solid and subsolid nodules. 1
Solid Nodules Management
Small Solid Nodules (<6 mm, <100 mm³)
- Low-risk patients: No routine follow-up needed
- High-risk patients: Optional CT at 12 months
- Special consideration: Certain high-risk patients with suspicious nodule morphology or upper lobe location may warrant 12-month follow-up 1
Intermediate Solid Nodules (6-8 mm, 100-250 mm³)
- Low-risk patients: CT at 6-12 months, then consider CT at 18-24 months if stable
- High-risk patients: CT at 3-6 months, then at 18-24 months if stable 1
Large Solid Nodules (>8 mm, >250 mm³)
- Consider CT at 3 months, PET/CT, or tissue sampling
- Management should be guided by the most suspicious features 1
Subsolid Nodules Management
Pure Ground Glass Nodules
- <6 mm: No routine follow-up
- ≥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 (these are difficult to characterize at this size)
- ≥6 mm: CT at 3-6 months to confirm persistence. If unchanged and solid component remains <6 mm, annual CT for 5 years
- Persistent part-solid nodules with solid components ≥6 mm should be considered highly suspicious 1
Multiple Nodules
- <6 mm: CT at 3-6 months. If stable, consider CT at 2 and 4 years
- ≥6 mm: CT at 3-6 months. Subsequent management based on the most suspicious nodule(s) 1
Risk Factors to Consider
Important risk factors that influence management decisions include:
- Smoking history
- Age
- Family history of lung cancer
- Previous history of malignancy
- Exposure to carcinogens
- Underlying lung disease 1
Technical Considerations
- All CT scans should be reconstructed with thin sections (≤1.5 mm, typically 1.0 mm) 1
- Coronal and sagittal reconstructions are strongly recommended 1
- Measurements should be made with electronic calipers or semi-automated methods 1
- For nodule size, use the average of long and short axes rounded to the nearest millimeter 1
Important Caveats
Benign-appearing nodules: No follow-up needed if they show diffuse, central, laminated or popcorn calcification, macroscopic fat, or typical perifissural nodules 1, 2
Incomplete thoracic CT scans: For small nodules (<6 mm) found on incomplete scans, no further investigation is typically needed. For intermediate-size (6-8 mm) nodules, follow-up CT of the complete chest is recommended 1
Special populations: These guidelines do not apply to lung cancer screening, patients with immunosuppression, or patients with known primary cancer 1
Measurement accuracy: Consistent measurement technique is crucial - use the same software for volumetric measurements when assessing growth 1, 3
Adherence challenges: Studies show poor adherence to Fleischner guidelines in clinical practice, with a tendency toward over-management of small nodules 4
The 2017 Fleischner Society guidelines represent a significant update from previous versions, with higher size thresholds for follow-up and less intensive follow-up for very small nodules, reflecting the extremely low risk of malignancy in nodules <6 mm, even in high-risk patients 1, 5.