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Lung Nodule
Aka: Lung Nodule, Pulmonary Nodule, Lung Mass, Lung Lesion, Coin Lesion of Lung, Solitary Lung Nodule, Solitary Pulmonary Nodule, Lung Incidentaloma, Lung Neoplasm, Lung Cancer Screening CT Chest, Mediastinal Mass
- See Also
- Incidentaloma
- Definition
- Lung Nodule
- Spherical opacity on xray <3 cm in diameter
- Completely surrounded by aerated lung
- Solitary Lung Nodule
- Isolated, single Lung Nodule
- Lung Mass
- Lung Lesion >3 cm diameter
- Considered to be Lung Cancer until proven otherwise
- Multiple Lung Nodules
- More than 10 diffuse Lung Nodule
- Epidemiology
- Lung Nodule Incidence
- Chest XRay: 0.2% of all Chest XRays identify a Lung Nodule
- CT Chest: 13-15% of all scans identify a Lung Nodule
- Background
- Obtain CT Chest to further evaluate Lung Mass identified on Chest XRay
- Evaluation below is based on the CT Chest
- Compare findings to prior imaging (critical!)
- Precautions
- Screening for Lung Nodules even in high risk groups (Tobacco users) has low yield of malignancy
- McWilliams (2013) N Engl J Med 369(10): 910-9 [PubMed]
- Differential Diagnosis: Lung Mass
- Benign
- Lung Hamartoma (10%)
- Infectious Granuloma (80%)
- Cryptococcosis
- Histoplasmosis
- Tuberculosis and atypical Mycobacteria
- Aspergillosis
- Coccidioidomycosis
- Other causes (uncommon to rare)
- Arteriovenous Malformation
- Intrapulmonary Lymph Node
- Sarcoidosis
- Malignant
- Lung Adenocarcinoma (60%)
- Lung Squamous Cell Carcinoma (20%)
- Metastasis to Breast, colon or Kidney (10%)
- Lung small cell carcinoma (4%)
- Other causes (uncommon to rare)
- Carcinoid Tumor
- Extranodal Lymphoma
- Differential Diagnosis: Anterior Mediastinal Mass (5 T's)
- Background: Seen on lateral Chest XRay obscuring heart-chest wall interface
- Thymoma (consider Myasthenia Gravis)
- Thyroid mass (retrosternal mass)
- Teratoma
- T-Cell Lymphoma
- "Terrible": Bronchogenic Carcinoma (most common cause)
- Imaging: Modalities
- Chest XRay (PA and lateral)
- Nodules at 5 mm may be visualized
- Poor Test Sensitivity (high False Negative Rate)
- Nodules often noted as incidental XRay finding
- CT Chest (thin slice)
- Greater Test Sensitivity and Test Specificity than Chest XRay
- CT is a first-line test in evaluation of Solitary Lung Nodules found on Chest XRay
- FDG-PET
- High Test Specificity and Test Sensitivity for Solitary Lung Nodules >8-10 mm
- Indicated when indeterminate findings persist on CT or findings discordant with estimated cancer risk
- MRI Chest
- Not recommended in evaluation of Solitary Lung Nodule
- Imaging: Red flag findings on CT Chest (suggestive of malignancy)
- Non-calcified or eccentric calcification
- Nodule size >8 mm
- Contrast with benign lesions which are typically <5 mm in size
- Irregular or spiculated border
- Contrast with benign lesions which have a smooth border
- Non-solid, ground-glass appearance
- Contrast with benign lesions that are dense and solid
- Doubling time between 1 month and 1 year
- Contrast with benign lesions that double in weeks or over years
- Risk Factors: Lung Cancer (used below to distinguish low risk from high risk)
- Current or past Tobacco use
- Odds Ratio 7.9 for >7 mm Nodule (OR 2.2 for >4 mm Nodule)
- Age over 40 years
- Asbestos Exposure
- Family History of Lung Cancer
- History of prior malignancy
- New Lung Nodule is an ominous finding in a patient with prior Lung Cancer history
- New Lung Nodule has a 25% risk of malignancy in a patient with extrathoracic cancer history
- Odds Ratio: 3.8 (for >4 mm Nodule)
- Worrisome findings on imaging (general)
- Nodule >8 mm
- Irregular borders
- Eccentric calcification or non-calcified
- Spiculation
- Odds Ratio 2.8 for >4 mm Nodule
- Non-solid or subsolid Nodule (ground glass or part solid)
- Size doubling time 1 month to 1 year (infection more likely with faster growth <1 month)
- Upper lobe location
- Swenson (1997) Arch Intern Med 157: 849-55 [PubMed]
- Contrast enhancement
- Non-enhancing lesion has 97% Negative Predictive Value for cancer
- Swenson (2000) Radiology 214: 73-80 [PubMed]
- Non-calcified lesion
- Calcification either centrally or completely suggests a benign lesion
- Semi-solid Nodules or subsolid/non-solid (63% malignant)
- Contrast with 18% malignancy with ground-glass lesions
- Contrast with 7% malignancy with solid lesions
- Henschke (2002) AJR 178: 1053-7 [PubMed]
- Size (most important factor)
- Size 2-5 mm: Less than 1% malignancy risk
- Size 5-10 mm: 6-28% malignancy risk
- Size 11-20 mm: 33-60% malignancy risk
- Size 20-30 mm: 64-82% malignancy risk
- Wahidi (2007) Chest 132: 94-107 [PubMed]
- References
- Swensen (2003) Radiology 226(3): 756-61 [PubMed]
- Gould (2007) Chest 131(2): 383-8 [PubMed]
- Evaluation: Nodule 8-30 mm
- General
- Discuss with pulmonology, thoracic surgery or radiology for work-up
- Some Lung Nodules may be distinguished as benign by appearance
- Benign calcified lesions (old ganuloma)
- Vascular pattern consistent with hamartoma or Arteriovenous Malformation
- Cancer probability (used below) is calculated from VA Model or Mayo Model
- Consider starting preoperative evaluation while awaiting biopsy
- Pulmonary Function Tests
- Electrocardiogram and other cardiac testing as needed
- Optimize comorbid conditions
- Low probability of cancer (<5% chance of cancer)
- Repeat Non-contrast CT chest in 3, 6, 9-12 and 18-24 months
- Intermediate probablity of cancer (5-65% chance of cancer)
- Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET)
- Preferred modality (with biopsy) as of 2013 ACCP Guidelines (esp. with pretest probability >5%)
- Interpretation
- Negative or mild update
- Follow low probability CT protocol as above
- Moderate or intense uptake
- Obtain biopsy via techniques below
- Biopsy techniques (for moderate or intense uptake on FDG-PET)
- CT chest with trans-thoracic fine needle aspirate (TTNA)
- Prior to FDG-PET, was first choice due to high Specificity (97%) and high sensitivity (90%)
- Schreiber (2003) Chest 123:1155 [PubMed]
- Bronchoscopy with biopsy
- Video assisted thoracoscopic surgery with frozen sections and resection
- High probability of cancer (>65% chance of cancer)
- Perform staging including evaluation for metastases
- Consider Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) for staging
- Video assisted thoracoscopic surgery with frozen sections and resection
- Indicated if no metastases
- Evaluation: Nodule <8 mm
- Approach to surveillance imaging for small Nodules
- Unless otherwise specified, use low-dose, non-contrast CT Chest for surveillance (lower radiation)
- Malignant Nodules double in volume within 400 days
- A Lung Nodule without change over 2 years is considered benign
- Exception: Ground glass lesions have slower doubling time and require longer observation
- High risk patients have Lung Cancer risk factors
- Tobacco Abuse history
- Age >65 years old
- Malignancy history
- Nodule 6-8 mm
- Low risk patient
- Repeat noncontrast CT chest in 6-12 months AND
- Repeat noncontrast CT chest again in 18-24 months
- If suspicious findings on CT, use thin section CT, and repeat CT chest to 3 years
- High risk patient
- Repeat noncontrast CT chest in 3-6 months AND
- Repeat noncontrast CT chest again in 9-12 months AND
- Repeat noncontrast CT chest again in 24 months
- Nodule 4-6 mm
- Low risk patient
- Repeat noncontrast CT chest in 12 months
- If normal repeat CT, no further evaluation is needed
- High risk patient
- Repeat noncontrast CT chest in 6-12 months AND
- ' Repeat noncontrast CT chest again in 18-24 months
- Nodule <4 mm
- Low risk patient
- No follow-up needed
- Optional follow-up noncontrast CT chest at 12 months
- High risk patient
- Repeat noncontrast CT chest in 12 months
- If normal repeat CT, no further evaluation is needed
- Evaluation: Subsolid Lung Nodules (semi-solid, non-solid)
- Solitary pure-ground glass Nodule
- Lung Nodules <=5 mm require no further CT follow-up
- Lung Nodules >5 mm
- Repeat noncontrast chest CT at 3 months AND
- Repeat noncontrast CT chest annually for at least 3 years
- Solitary part-solid Nodule
- Repeat noncontrast chest CT at 3 months to confirm persistence
- Persistent Nodules <5 mm
- Repeat noncontrast CT chest annually for at least 3 years
- Persistent Nodules >5 mm
- Refer for Nodule biopsy or Nodule resection
- Multiple Nodules
- Discuss with pulmonology, thoracic surgery or radiology for CT surveillance versus Nodule biopsy
- Evaluate for malignancy probability
- Evaluation: Lung Cancer Screening low-dose, noncontrast CT Chest
- Annual Screening low dose noncontrast CT Chest Indications (USPTF and medicare recommendations)
- Adults 55 to 77 years old with >30 pack year history of smoking AND
- Currently smoking or quit within last 15 years
- Negative noncontrast CT Chest
- Criteria
- No Lung Nodules OR
- Lung Nodules with specific calcification pattern (complete, central or popcorn calcification)
- Approach
- Consider repeat low-dose, noncontrast CT Chest in 12 months
- Benign noncontrast CT Chest
- Criteria
- Solid Lung Nodules (<6 mm or new Nodules <4 mm) OR
- Part-solid Lung Nodules <6 mm total diameter at baseline OR
- Ground-glass Lung Nodules <20 mm OR unchanged/slowly growing and >20 mm
- Approach
- Consider repeat low-dose, noncontrast CT Chest in 12 months
- Probably benign noncontrast CT Chest
- Criteria
- Solid Lung Nodules (6-8 mm or new Nodules 4-6 mm) OR
- Part-solid Lung Nodules >=6 mm total diameter AND solid component <6 mm OR
- Ground-glass Lung Nodules >=20 mm (baseline CT or new)
- Approach
- Repeat low-dose, noncontrast CT Chest in 6 months
- Suspicious noncontrast CT Chest
- Criteria
- Solid Lung Nodules (8-15 mm or growing at <8 mm or new 6-8 mm) OR
- Part-solid Lung Nodules >=6 mm total diameter AND solid component 6-8 mm OR
- Endobronchial Nodule
- Approach
- Repeat low-dose, noncontrast CT Chest in 3 months
- Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) when >=8 mm solid component
- Very suspicious noncontrast CT Chest
- Criteria
- Solid Lung Nodules (>=15 mm or growing at >8 mm)
- Approach
- Chest CT with and without contrast
- Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) when >=8 mm solid component
- References
- ACR Guidelines (accessed 12/14/2015)
- https://www.acr.org/~/media/ACR/Documents/PDF/QualitySafety/Resources/LungRADS/AssessmentCategories.pdf
- Resources
- Online calculator of Lung Cancer risk
- http://www.yourdiseaserisk.wustl.edu/
- http://reference.medscape.com/calculator/solitary-pulmonary-nodule-risk
- Establishes pretest probability of cancer and helps drive evaluation based on patient risk
- References
- Midthun (2011) Internal Medicine, Mayo Conference, Kauai
- Swadron (2019) Pulmonary 2, CCME Emergency Medicine Board Review, accessed 6/16/2019
- Albert (2009) Am Fam Physician 80(8): 827-31 [PubMed]
- Gould (2013) Chest 143(5 suppl):e935-1205 +PMID:23649456 [PubMed]
- Gould (2007) Chest 132(suppl 3):108S-130S [PubMed]
- Hitzeman (2014) Am Fam Physician 90(11): 784-9 [PubMed]
- Kikano (2015) Am Fam Physician 92(12): 1084-91 [PubMed]
- MacMahon (2005) Radiology 237(2):395-400 [PubMed]