A 65-year-old man with a 40-year smoking history presents with a 4 cm left upper lobe lung mass on CT. Serum CEA is 8.2 ng/mL (normal <5). Bronchoscopy shows adenocarcinoma. PET-CT shows no distant metastases. What is the most appropriate next step in management?

Explanation

## CEA in Lung Cancer: Role and Limitations **Key Point:** CEA is a nonspecific tumor marker elevated in ~60% of lung adenocarcinomas and correlates with prognosis, but does NOT guide diagnosis or immediate treatment decisions. Histology is already confirmed (adenocarcinoma); next step is complete staging and surgical evaluation. **Clinical Pearl:** CEA elevation in lung cancer indicates: - Worse prognosis - Useful for monitoring treatment response (not diagnosis) - NOT used to determine histological subtype **High-Yield Facts:** - **NSE/ProGRP** are markers for small-cell lung cancer (SCLC), not adenocarcinoma - **CEA** is nonspecific; elevated in adenocarcinoma, large-cell, and some squamous cell carcinomas - **Staging before treatment** is mandatory: brain MRI (CNS metastases), bone scan or PET-CT (osseous involvement), cardiac assessment - **Surgical resection** is the treatment of choice for stage I–IIIA NSCLC without distant metastases **Management Sequence:** Histology → Complete staging → Surgical/oncology consultation → Treatment