Small Cell vs Non-Small Cell Lung Cancer: Key Differences

The main differences between small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) include:

1. Cell Type & Growth Pattern

• SCLC: Composed of small, round, poorly differentiated neuroendocrine cells that grow rapidly and spread early.
• NSCLC: Includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma; these grow more slowly and tend to be more localized initially.

2. Association with Smoking

• SCLC: Almost exclusively seen in heavy smokers.
• NSCLC: Can occur in smokers and non-smokers (especially adenocarcinoma).

3. Location in the Lungs

• SCLC: Typically central (near the bronchi).
• NSCLC: Can be central (squamous) or peripheral (adenocarcinoma).

4. Metastasis & Prognosis

• SCLC: Highly metastatic, often diagnosed at an advanced stage. Poor prognosis.
• NSCLC: Spreads more slowly, often diagnosed earlier, and has a better prognosis.

5. Paraneoplastic Syndromes

• SCLC: More likely to cause paraneoplastic syndromes (e.g., SIADH, Cushing’s syndrome, Lambert-Eaton syndrome).
• NSCLC: Can cause hypercalcemia (especially squamous cell carcinoma due to PTHrP production).

6. Treatment Approach

• SCLC: Not surgically resectable in most cases; treated primarily with chemotherapy and radiation due to early metastasis.
• NSCLC: If caught early, can be treated with surgery, chemotherapy, radiation, and targeted therapy (EGFR, ALK, PD-L1 inhibitors).