Non small cell lung cancer diagnostic study of choice

Template:Non-small cell lung cancer Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Furqan M M. M.B.B.S[2]

Overview

Chest X-Ray is the initial study performed when non-small cell lung cancer is suspected. Lung CT scan is the diagnostic study of choice for the diagnosis of non-small cell lung cancer. Endobronchial ultrasound is a first-line diagnostic modality for the mediastinal staging of the non-small cell lung cancer. The lung biopsy is the gold standard for the diagnosis of the non-small cell lung cancer. The lung biopsy helps to differentiate between the various subtypes of lung cancer.

Diagnostic Study of Choice

Study of choice

Chest X-Ray is the initial study performed when non-small cell lung cancer is suspected. However, computed tomography is the diagnostic study of choice for the diagnosis of non-small cell lung cancer. On CT, characteristic findings of non-small cell lung cancer include:

Adenocarcinoma of the lung

• Lung adenocarcinomas are typically peripherally located
• Usually measure <4 cm in diameter, very few show cavitation
• Perihilar and mediastinal involvement
• Ground glass opacity (slow growth), usually lesions double the size within a year

Squamous cell carcinoma of the lung

• Centrally located within the lung
• Usually measure larger than 4 cm in diameter
• Frequent cavitation
• Commonly cause segmental or lobar lung collapse due to the central location

Large cell carcinoma of the lung

• Rapid growth
• Early metastasizes to the mediastinum and brain
• Large mediastinal nodules/masses
• Lymph node involvement (frequently subcarinal)
• Nodular pleural thickening
• Pleural effusion

• The CT scan should be performed when the following is required:
• Assessment of the main bronchi
• Evaluation of the entire thorax
• Detection of chest wall invasion
• Assessment of hilar and mediastinal invasion/adenopathy
• Determination of non-small cell lung cancer staging
• Precise determination of size and tumor dimensions
• Detection of liver, bone, adrenal , and brain metastasis

Bronchoalveolar carcinoma

• Subtype of adenocarcinoma
• Single pulmonary nodule or mass
• Multicentric or diffuse disease
• Localized area of parenchymal consolidation
• Bubble-like areas of low attenuation within the mass are a characteristic finding
• Hilar and mediastinal lymphadenopathy is uncommon
• Persistent peripheral consolidation with associated nodules

Diagnostic modality for staging

Endobronchial ultrasound is a first-line diagnostic modality for mediastinal staging.The sensitivity of endobronchial ultrasound is 90% and specificity is 97%.

• On ultrasound (endobronchial ultrasound), characteristic findings of non-small cell lung cancer include:
  • Enlarged lymph nodes
  • Local invasion of adjacent bronchial structures and mediastinum

• Indications for the endobronchial ultrasound:
  • Evaluation of lymph nodes and other structures in the mediastinum
  • Mediastinal invasion staging
  • Determination of management strategy
  • Real-time evaluation of structures

Gold standard

• Lung biopsy is the gold standard test for the diagnosis of non-small cell lung cancer.

Diagnostic results

The diagnostic result of lung biopsy is confirmatory of non-small cell lung cancer and depends on the type of cancer. Click here to view the biopsy findings of the subtypes.

Sequence of Diagnostic Studies

The sequence of the diagnostic studies depends upon the stage of cancer. Click here to view detailed sequential management of different stages.

Evaluation Algorithm for Suspected Non-Small Cell Lung Cancer

The algorithm below summarizes the initial imaging approach for patients with suspected non-small cell lung cancer.

Imaging approach ❑ Suspected lung cancer

Chest X Ray normal?

No

Yes

Enhanced Computed Tomography (ECT), includes: ❑ Thorax ❑ Upper Abdomen ❑ Low Neck

Manage and observe

Imaging evaluation

Location ❑ Central ❑ Peripheral ❑ Pleural lesion Size Lesion characteristics ❑ Margins (irregular/regular) ❑ Shape (spiculated/rounded) Presence of cavitation ❑ Yes ❑ No Type of adenopathy ❑ Hiliar ❑ Mediastinal

Diagnosis and Staging Assessment

Other Imaging or Diagnostic Modalities ❑ Sputum cytology ❑ Endobronchial ultrasound ❑ Endoscopic ultrasound ❑ Bronchoscopy ❑ Mediastinoscopy ❑ PET/CT

Biopsy