How do you stage small cell lung cancer (SCLC)?

Staging Small Cell Lung Cancer (SCLC)

Small cell lung cancer is staged using either the two-stage system (limited vs. extensive disease) or the TNM staging system, with comprehensive imaging including CT, brain MRI, and PET/CT being essential components of accurate staging. 1

Two-Stage Classification System

• Limited-Stage Disease: Defined as disease confined to a single radiation port (typically one hemithorax), including the primary tumor and regional lymph nodes 1
• Extensive-Stage Disease: Any tumor that extends beyond the boundaries of a single radiation port, including patients with ipsilateral lung metastases, malignant pleural or pericardial effusion, and distant metastases 1

TNM Staging System

• While the two-stage system has been traditionally used, the TNM staging system is also prognostic for SCLC and is increasingly being integrated into clinical practice 2, 3
• The TNM system allows for more precise assessments of prognosis and specific therapy planning 1, 2

Required Staging Procedures

Initial Evaluation

• Complete medical history and physical examination 1
• Pathologic review of biopsy specimens 1
• Laboratory studies: CBC, serum electrolytes, renal and liver function tests, lactate dehydrogenase (LDH) 1

Imaging Studies

• Contrast-enhanced CT scans of the chest and upper abdomen (including liver and adrenal glands) 1
• Brain imaging: MRI (preferred) or CT scan with contrast 1
• PET/CT scan: Recommended for patients with suspected limited-stage disease to assess for distant metastases 1
  • PET/CT increases staging accuracy with approximately 19% of patients being upstaged from limited to extensive stage 1
  • PET/CT is superior to standard imaging for most metastatic sites but inferior to MRI for brain metastases 1
• Bone scan: If PET/CT is equivocal or not available 1

Additional Procedures (When Indicated)

• Thoracentesis with cytologic analysis: For pleural effusions large enough to be safely accessed 1
  • If thoracentesis is negative, thoracoscopy can be considered to document pleural involvement 1
  • A pleural effusion should be excluded as a staging element if multiple cytopathologic examinations are negative, the fluid is not bloody/exudative, and clinical judgment suggests it's not directly related to cancer 1
• Bone marrow aspiration and biopsy: Only in select patients with peripheral cytopenia and no other evidence of metastatic disease 1
  • Bone marrow involvement as the only site of extensive disease occurs in fewer than 5% of patients 1
• Pathologic mediastinal staging: Required before surgical resection in patients with clinical stage T1-2, N0 disease 1
  • Can be performed via conventional mediastinoscopy or minimally invasive techniques (transesophageal endoscopic ultrasound-guided FNA, endobronchial ultrasound-guided transbronchial needle aspiration, or video-assisted thoracoscopy) 1

Important Staging Considerations

• Staging should not be limited to symptomatic sites or those suggested by laboratory tests 1
• Brain imaging can identify CNS metastases in 10-15% of patients at diagnosis, with approximately 30% being asymptomatic 1
• Bone scans are positive in up to 30% of patients without bone pain or abnormal alkaline phosphatase levels 1
• Staging should not delay treatment for more than 1 week due to the aggressive nature of SCLC 1

Prognostic Factors

• Poor prognostic factors: Poor performance status (3-4), extensive-stage disease, weight loss, and elevated LDH 1
• Favorable prognostic factors in limited-stage disease: Female gender, age <70 years, normal LDH, and stage I disease 1
• Favorable prognostic factors in extensive-stage disease: Younger age, good performance status, normal creatinine level, normal LDH, and a single metastatic site 1