THE SOLITARY PULMONARY NODULE: SPN - KAP P¢  THE SOLITARY PULMONARY NODULE: SPN BY Dr Mureithi C.J.M

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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

  • 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

    http://www.chestx-ray.com/spn/spnprob.html http://www.chestx-ray.com/spn/spnprob.html http://www.chestx-ray.com/spn/spnprob.html

  • 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

    http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5783450 http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5783450 http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5783450

  • 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