Fleischner 2017
Guidelines for management of incidental pulmonary nodules on CT
Average of long and short axis on axial images
For part-solid nodules only
Check all that apply. Any factor = HIGH risk patient.
Fleischner Society 2017 Guidelines
The Fleischner Society guidelines provide evidence-based recommendations for managing incidental pulmonary nodules detected on CT imaging. These guidelines help reduce unnecessary follow-up imaging and invasive procedures while ensuring appropriate surveillance of potentially malignant nodules.
When to Apply These Guidelines
These guidelines apply to incidental pulmonary nodules in adults aged 35 years or older. They do NOT apply to:
- Patients with known primary cancer (use oncology-specific guidelines)
- Immunocompromised patients
- Patients undergoing lung cancer screening (use Lung-RADS)
- Patients younger than 35 years
Nodule Classification
Solid Nodules
Completely soft tissue attenuation, obscuring the underlying lung parenchyma. Risk stratification is based on size and patient risk factors.
Ground-Glass Nodules (GGN)
Hazy increased attenuation that does not obscure underlying bronchial or vascular structures. Pure GGNs have lower malignancy risk but may represent adenocarcinoma spectrum lesions (atypical adenomatous hyperplasia, adenocarcinoma in situ).
Part-Solid Nodules
Mixed ground-glass and solid components. The solid component size is the key prognostic factor, correlating with invasive adenocarcinoma. Part-solid nodules have the highest malignancy risk among all nodule types.
Risk Factors for Malignancy
Patients are classified as HIGH RISK if they have ANY of:
- Smoking history - Current or former smoker
- Age > 40 years
- Family history - First-degree relative with lung cancer
- Environmental exposures - Asbestos, radon, uranium
- Upper lobe location (considered in clinical judgment)
- Spiculated margins (considered in clinical judgment)
Key Size Thresholds
| Nodule Type | Threshold | Significance |
|---|---|---|
| Solid | 6 mm | Below this, minimal follow-up in low-risk patients |
| Solid | 8 mm | Above this, consider PET/CT or biopsy |
| Subsolid (GGN/Part-solid) | 6 mm | Below this, no routine follow-up |
| Part-solid (solid component) | 6 mm | Above this, consider PET/biopsy/resection |
Measurement Technique
Nodule size should be measured as the average of long and short axis diameters on axial images. For part-solid nodules, measure both total size and solid component size. Measurements should be made on lung windows. Volume measurement, when available, may provide more accurate growth assessment.
References
- MacMahon H, Naidich DP, Goo JM, et al. Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017. Radiology. 2017;284(1):228-243. doi:10.1148/radiol.2017161659
- Naidich DP, Bankier AA, MacMahon H, et al. Recommendations for the Management of Subsolid Pulmonary Nodules Detected at CT: A Statement from the Fleischner Society. Radiology. 2013;266(1):304-317. doi:10.1148/radiol.12120628
- Gould MK, Donington J, Lynch WR, et al. Evaluation of Individuals With Pulmonary Nodules: When Is It Lung Cancer? Diagnosis and Management of Lung Cancer, 3rd ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2013;143(5 Suppl):e93S-e120S. doi:10.1378/chest.12-2351
- Bankier AA, MacMahon H, Goo JM, et al. Recommendations for Measuring Pulmonary Nodules at CT: A Statement from the Fleischner Society. Radiology. 2017;285(2):584-600. doi:10.1148/radiol.2017162894
- Henschke CI, Yankelevitz DF, Mirtcheva R, et al. CT Screening for Lung Cancer: Frequency and Significance of Part-Solid and Nonsolid Nodules. AJR Am J Roentgenol. 2002;178(5):1053-1057. doi:10.2214/ajr.178.5.1781053