the solitary pulmonary nodule: spn - kap...
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THE SOLITARY PULMONARY NODULE: SPN
BY Dr Mureithi C.J.M. & DR NYALE G.M Consultant Physician/ Pulmonologist
TKH
“Practical management tips” Importance cum difficulty of arriving at a diagnosis
DEFINITION
• A single discrete
– pulmonary opacity that is surrounded by normal lung tissue
– that is not associated with adenopathy or atelectasis
• 3cm or less in diameter
• Aka: coin lesion, small pulmonary peripheral lesions, T1N0M0 (TNM7).
Prevalence
• 1 - 2 per 1000 CXR (90% CO-INCIDENTAL)
– failure rate to Dx SPN on CXRs:25 - 90% CHEST 2003; 123:89S–96S
• CT scan screening: higher prevalence's.
• Local data: ? KENYA – A recent study in Cape Town of resectable lung cancer Median size of
tumour at DX was 61.5 mm Nanguzgambo A. J Thorac Oncol. 2011 Feb;6(2):343-50
• overall malignancy rate of 10-68%
Major Question: is this a cancer?
Fishman’s Pulmonary Diseases and Disorders;4th Edition, 2008
Risk factors for malignancy
• Age
• smoking history:
• prior history of malignancy.
Nodule x-ristics associated with malignancy
• Nodule size
• Edges
• Consistency / Cavitations
• Calcification
• Growth rate
• Densitometry
• Location
• Metabolic rate
Radiology 2005; 237:395–400
Risk factors for malignancy
www.chestx-ray.com/spn/spnprob.html
Nodule size
• < 5 mm: 0 to 1% malignant
• 5 to 10 mm: 6 to 28% malignant
• > 20 mm: 64 to 82% malignant
• masses(>3 cm): 80 to 99 % malignant
CHEST 2007; 132:94S–107S
Edges/margins/borders
Fishman’s Pulmonary Diseases and Disorders;4th Edition, 2008
Increased cancer risk
smooth edges: 20 - 30%; irregular, lobulated, or spiculated: 33 - 100%
Nodule consistency • Solid: 7 to 9% malignancy
• Non-solid nodules:18% malignancy
• Partially Solid: 63% malignancy
• Densitometry:> 185 hu <9% cancer
• Cavity wall:
– <5 mm = 95% benign
– 5 to 15 mm = 73% benign
– >15 mm = 84% malignant
Calcification patterns
SPNs Growth rate: Volume Doubling Time (VDT)
• Volume = 4/3(π)r3 or 1/6(π)D3
E.g: 10mm SPN ------> 13mm --------------> 20mm
(0.524ml) (1.151 ml) (4.190 ml)
• Benign SPNs VDT: < 20 days OR > 400 days.
• Traditional practice: repeat CT scans @ at 3, 6, 12, and 24 months.
CXR • Threshold Nodule size
diameter 0.8 -1cm
• Margin: smooth, irregular, lobulated, or
spiculated (corona radiata)
• Calcification
• Growth rate: past CXR (last 2 yrs)
• if absent = rapid growth hence malignancy unlikely
• Not changed in size = benign
• Present but slow growing = ?malignant
Popcorn calcification
Radiology 2005; 237:395–400
CT SCAN • picks 40 % more (>CXR)
• 3D location
• adjacent structures / remaining lung
• More detail on SPN e.g fat
• helps in staging
• assessing accessibility in Sx /Bx Popcorn calcification
Radiology 2005; 237:395–400
HRCT • Same as CT but refined detail: ? Necessity
• Lower sensitivity & specificity
• Covers only 10% of lung
Another reason why doctors need better pay!
blackberry phones!
• http://www.chestx-Ray.com/spn/spnprob.html
Lung cancer risk calculator models
MAYO MODEL • N = 629 (Males=51%); size= 4–30 mm)
Pre-test probability of a malignant SPN = ex/(1+ex) x = 26.8272 + (0.0391*age) + (0.7917*smoke) +(1.3388*cancer) +
(0.1274*diameter) + (1.0407*spiculation)+ (0.7838*upper) Where: e =the base of the natural logarithm age=patient’s age in years smoke = smoking history (1 =current or former smoker, 0 = never smoker) cancer =extrathoracic CA >5 years (1 = yes, 0 = no or not specified) Diameter= largest nodule measurement (in mm) on initial CXR/ CT scan Spiculation = spiculation on imaging (1 = yes, 0 =no or not specified) upper = location in upper lobe/s (1 = yes, 0 = no).
Mayo clin proc 1999; 74: 319 – 329
VA MODEL • N=375 patients (98%male); size = 7–30 mm
Pre-test probability of a malignant SPN = ex/(1+ex)
x =28.404+ (2.061*smoke) + (0.779*age10) + (0.112*diameter) 2 (0.567*yearsquit10)
Where:
e = the base of the natural logarithm
smoke =smoking Hx (1 = current or former smoker, 0 = neversmoker)
age10 = age in years at Dx SPN divided by 10
Diameter= the largest in mm reported on initial CXR/CTscan
yearsquit10 = the number of years sincequitting smoking, divided by 10 (0 indicates not applicable).
CHEST 2007; 131:383–388
Management
• Low Probability (< 10%) – Follow with serial CT scans – Traditionally q3 months X 4 q6 months X 2 – ? Tissue sampling in future
• Intermediate Probability (10 – 60%)
– additional imaging – Tissue Sampling
• High Probability (>60%) – Excision – Imaging to r\o metastasis and stage patient.
Management outline for SPNs
Fishman’s Pulmonary Diseases and Disorders;4th Edition, 2008
SPN - follow up
Radiology 2005; 237:395–400
Additional Imaging
“For the indeterminate SPNs /staging”
Incremental dynamic CT (Contrast enhancement)
• Principle: Malignant SPNs have greater vascularity than benign nodules.
• uses serially increasing doses of iodinated IV contrast to
look for enhancement of nodules • < 15 HU = benign :> 20 HU =malignant (sensitivity: 98 -
100%; specificity: 54 - 93%)
CHEST 2007; 132:94S–107S
PET SCAN • Based on increased glucose uptake and
metabolism by tumor cells.
• standardized uptake ratio/value (SUR/V): malignancy >2.5
• low sensitivity in SPNs < 1 cm. – new evidence of good sensitivity in 0.8 – 1 cm
• Detects mediastinal metastases/ staging
Am J Respir Crit Care Med 183;2011
PET SCAN • A meta-analysis of 13 studies (n= 450)
: – sensitivity = 94.3%, – specificity = 83.3%.
– False-negative:
• BAC, • Carcinoids
• mucinous adenocarcinomas.
– False-positives: • granulomatous infections e.g. TB, fungi • inflammatory conditions e.g. R.A, sarcoidosis • uncontrolled hyperglycemia
• high negative predictive value:
– low-risk pts (Prob < 20%) + Neg PET= < 1% Malignancy
– high-risk pts (Prob >80%) + Neg PET = 14%
malignancy
Am J Respir Crit Care Med 183;2011
PET/CT
+ =
Am J Respir Crit Care Med 183;2011
PET/CT • Very good is determining SPN size (T stage)
• High NPV (esp Nodal spread ->no need for mediastinoscopy)
• Detects extra-thoracic metastasis better
• Reduces thoracotomies (total & futile)
• Mortality same as in PET alone
1. N Engl J Med 2003;348:2500-7.
2. Radiology 2003;229:526-33
3. Ann Thorac Surg 2004;78:1017-23
4. J Nucl Med 2007; 48:1761–1766
5. N Engl J Med 2009;361:32-9.
Tissue Dx
“Ultimate
Diagnosis”
Nodule Sampling
• Bronchoscopic techniques
• Percutaneous needle aspiration/ biopsy
• Surgically: VATS / Thoracotomy
Decision depends on: size, location, local expertise
New & future advances
spherical harmonics (SHs)
• Principle: malignant nodules have more complex shapes (e.g. spiculated) than benign nodules (e.g. smoothed)
Step 1 Step 3
Step 2
From Nano to Macro, 2011 IEEE International Symposium on Biomedical Imaging;March 30 2011-April 2 2011 Chicago, IL, USA
Perfusion CT “dynamic area-detector CT” • Uses a quantitative first-pass perfusion 256 0r 320–detector row (CT) already in
use for brain, heart, and pancreas. (functional CT) • Principle: malignant nodules have higher blood flows and higher metabolism
hence extract more oxygen
• Potentially more specific and accurate than PET/CT
Radiology: Volume 258: Number 2—February 2011
Radiology: Volume 258: Number 2—February 2011
Virtual bronchoscopy (VB) + EBUS-GS
Am J Respir Crit Care Med 183;2011
Locatable Guide (LG):
360° steerability for
navigation to lesions and
lymph nodes
Extended Working
Channel (EWC): Lock
EWC in place for
insertion of biopsy tools
and other catheters Patient Sensor Triplets:
Placed on patient and are
tracking sensors to show LG
position and account for
patient movement
Location Board: creates
electromagnetic field
Bronchoscopic Access:
LG and EWC go through
mouth/nose to steer through
bronchial tree to lesions and
lymph nodes
Planning Screen
New lung cancer genes
• GWAS identified a SNP close to NAT subunit with susceptibility to lung cancer at 15q24–15q25.1 (markers rs1051730 andrs8034191)
• low- penetrance,
• high-frequency in lung-cancer pts
• risk may be independent of smoking behavior.
• Confirmed by 3 large GWAS – Amos CI et al. Genome-wide association scan of tag SNPs identifies a susceptibility locus for lung
cancer at 15q25.1. Nat Genet 2008;40:616-22
– Hung RJ et al.A susceptibility locus for lung cancer maps to nicotinic acetylcholine receptor subunit genes on 15q25. Nature 2008;452:633-7.
– Thorgeirsson TE et al. A variant associated with nicotine dependence, lung cancer and peripheral arterial disease. Nature 2008;452:638-42
1. N Engl J Med 2008;359:1367-80.
2. N Engl J Med 2008;359:2143-53.
Thank you for your attention
Judas, what are the coins for?
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