Cardiothoracic Surgery: Lung Cancer Diagnosis & Staging

Radiographic Diagnosis

General Screening

Imaging

  • Primary Modality: Chest CT
    • Extended to Include Upper Abdomen, Liver & Adrenal Glands
    • Best Test for T/N Status
  • Whole-Body PET
    • Should be Obtained in All Potentially Operable Candidates – May Decrease the Risk of Futile Surgery if Metastases Found
    • Routine Use Controversial – No Evidence of Improved Survival

Solitary Pulmonary Nodule (SPN) Features

  • Benign Features:
    • Size < 5 mm
    • Size Remains Stable
    • Fat with a Smooth Border
    • Calcification (Popcorn, Central, Diffuse or Lamellated)
      • Eccentric or Punctate Calcification are Nonspecific & May Be Malignant
    • Low Enhancement < 15 Hounsfield Units
  • Malignant Features:
    • Size > 20 mm
    • Size Doubles in Less Than 1 Year
    • Spiculated or Lobular Border
    • High Enhancement > 20 Hounsfield Units

Solitary Pulmonary Nodule CXR 1

Malignant Solitary Pulmonary Nodule, 2.5 cm with Speculated Borders 2

Lung RADS Assessment

Score Category Findings Management Risk of Malignancy
0 Incomplete Prior Chest CT Used for Comparison or Part of Lung Cannot Be Visualized Additional Imaging or Comparison to Prior Imaging N/A
1 Negative No Lung Nodules or Nodules with Specific Benign Calcifications Continue Annual Screening < 1%
2 Benign Solid: < 6 mm or New < 4 mm
Part-Solid: < 6 mm
Non-Solid: < 30 mm or ≥ 30 mm & Unchanged or Slowly Growing
Category 3 or 4 Nodules Unchanged for ≥ 3 Months		 Continue Annual Screening < 1%
3 Probably Benign Solid: ≥ 6 mm or New ≥ 4 mm
Part-Solid: ≥ 6 mm or New < 6 mm
Non-Solid: ≥ 30 mm		 Repeat CT in 6 Months 1-2%
4A Suspicious Solid: ≥ 8 mm, Growing < 8 mm or New ≥ 6 mm
Part-Solid: Solid Component ≥ 6 mm or New/Growing < 4 mm Solid Component
Endobronchial Nodule		 Repeat CT in 3 Months; Add PET/CT if There is a Solid Component ≥ 8 mm 5-15%
4B Very Suspicious Solid: ≥ 15 mm or New/Growing ≥ 8 mm
Part-Solid: Solid Component ≥ 8 mm or New/Growing ≥ 4 mm Solid Component		 CT, PET/CT and/or Biopsy > 15%
4X Category 3 or 4 Nodules with Additional Features that Increase the Suspicion of Malignancy > 15%
S Clinically Significant or Potentially Clinically Significant Findings (Non-Lung Cancer) Modifier – May Add on to Category 0-4 As Indicated N/A
C Prior Diagnosis of Lung Cancer Modifier – May Add on to Category 0-4 As Indicated N/A

Tissue Diagnosis

Biopsy

  • Biopsy Required for Diagnosis
  • Biopsy Techniques:
    • Bronchoscopic Biopsy
      • Preferred for Large Central Lesions
    • Transthoracic (Percutaneous) Biopsy
      • Preferred for Small Peripheral Lesions
      • Higher Rate of Indeterminate Diagnoses Due to Smaller Sample Size
    • Thoracoscopic (Surgical) Biopsy
      • Often Preferred for Early-Stage Peripheral Lesions – Resection May Be Curative

Lymph Node Sampling – Indications

  • Size > 1 cm on CT
  • “Hot” Nodule (FDG Uptake Greater than Mediastinal Blood Pool) on PET

Lymph Node Sampling – Approaches

  • Anterior Mediastinotomy (Chamberlain Procedure)
  • Endoscopic Assessment:
    • Esophagoscopy & Endoscopic Ultrasound (EUS)
    • Endobronchial Ultrasound (EBUS)
  • Mediastinoscopy
  • Mediastinal Lymph Node Dissection (MLND)

Approach to Lymph Node Sampling

Anterior Mediastinotomy (Chamberlain Procedure)

  • Samples: Aortic Nodes
    • Station 5 (Aortopulmonary Window)
    • Station 6 (Para-Aortic)
  • Procedure: Left Anterior Thoracotomy & Parasternal Mediastinoscopy
  • Relative Contraindications:
    • Large Ascending Aortic Aneurysm
    • Past Thoracic Surgery or Radiation
    • SVC Syndrome

Esophagoscopy & Endoscopic Ultrasound (EUS)

  • Samples: Posterior-Inferior Mediastinum
    • Station 8 (Paraesophageal – Below Carina)
    • Station 9 (Pulmonary Ligament)

Endobronchial Ultrasound (EBUS)

  • Samples: Anterior/Superior Mediastinum & Intrapulmonary
  • Anterior/Superior Mediastinum
    • Station 1 (Low Cervical)
    • Station 2 (Paratracheal – Upper)
    • Station 4 (Paratracheal – Lower)
    • Station 7 (Subcarinal)
  • Intrapulmonary
    • Station 10 (Hilar)
    • Station 11 (Interlobar)
    • Station 12 (Lobar)

Mediastinoscopy

  • *Old Gold Standard Before Endoscopic Procedures
  • Samples: Stations 2, 4 & 7
  • Would Still Need Mediastinotomy for Aortopulmonary Nodes

Mediastinal Lymph Node Dissection (MLND)

  • Intraoperative Staging During Lung Resection
  • Gold Standard Although Clinical Use is Controversial & Many Prefer Systematic Sampling
  • Samples: Stations 2R, 4R & 5-10
    • Can Also Access Station 3 if Necessary

Staging

TNM Staging

  T N M
1 ≤ 3 cm
1a: ≤ 1 cm
1b: > 1 cm
1c: > 2 cm		 Ipsilateral Peribronchial or Hilar LN, or Intrapulmonary LN 1a: Separate Nodule in Contralateral Lobe, Malignant Pleural Effusion or Malignant Pericardial Effusion
1b: Single Extrathoracic Met
1c: Multiple Extrathoracic Mets
2 > 3 cm but ≤ 5 cm or Involves the Main Bronchus, Invades Visceral Pleura or Has Associated Atelectasis or Obstructive Pneumonitis
2a: > 3 cm
2b: > 4 cm		 Ipsilateral Mediastinal or Subcarinal LN
3 > 5 cm but ≤ 7 cm
Has Separate Nodule in the Same Lobe
Directly Invades the Chest Wall, Phrenic Nerve or Parietal Pericardium		 Contralateral, Scalene or Supraclavicular LN
4 > 7 cm
Has a Separate Nodule in a Different Ipsilateral Lobe
Invades the Diaphragm, Mediastinum, Heart, Great Vessels, Trachea, Recurrent Laryngeal Nerve, Esophagus, Carina or Vertebral Body

Stage

Stage T N M
I A1 T1a N0 M0
A2 T1b N0 M0
A3 T1c N0 M0
B T2a N0 M0
II A T2B N0 M0
B T1-2 N1 M0
T3 N0 M0
III A T1-2 N2 M0
T3 N1 M0
T4 N0-1 M0
B T1-2 N3 M0
T3-4 N2 M0
C T3-4 N3 M0
IV A Any T Any N M1a-b
B Any T Any N M1c

References

  1. Carvalho A, Correia R, Sá Fernandes M, Pinheiro J, Leitão P, Padrão E, Pinto D, Pereira JM. Pulmonary inflammatory myofibroblastic tumor: report of 2 cases with radiologic-pathologic correlation. Radiol Case Rep. 2017 Apr 1;12(2):251-256.(License: CC BY-NC-ND-4.0)
  2. Ozkaya S, Findik S, Atici AG. Penile metastasis as a first sign of lung cancer. Int Med Case Rep J. 2009 Jul 16;2:19-21. (License: CC BY-NC-3.0)