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# Tracheal, Bronchial, and Lung Cancer: Comprehensive Guide ## Introduction: The Silent Epidemic Lung cancer remains the **leading cause of cancer mortality worldwide**, responsible for approximately 1.8 million deaths annually. This malignancy originates in the respiratory epithelium of the tracheobronchial tree and manifests in two primary forms: **non-small cell lung cancer (NSCLC)** (85% of cases) and the more aggressive **small cell lung cancer (SCLC)**. Alarmingly, 20-25% of new diagnoses occur in lifelong non-smokers, with women disproportionately affected. The five-year survival rate varies dramatically from 60% for localized disease to a dismal 8% for metastatic cases, underscoring the critical importance of early detection. --- ## Causes and Risk Factors: Beyond Smoking ### Primary Risk Factors - **Tobacco Exposure**: Accounts for 80-90% of cases. Smokers have 15-30× higher risk than non-smokers - **Radon Gas**: Second leading cause. This radioactive gas seeps from soil into buildings - **Occupational Hazards**: Asbestos (mesothelioma risk), silica, diesel exhaust, and arsenic - **Air Pollution**: PM2.5 particles penetrate deep into lung tissue ### Emerging Risks - **Genetic Predisposition**: EGFR mutations in non-smokers (especially Asian women) - **Previous Lung Diseases**: COPD increases risk 4-6× - **HIV Infection**: 2× higher risk independent of smoking --- ## Prevention Strategies: A Multifaceted Approach ### Primary Prevention - **Smoking Cessation Programs**: Risk halves after 10 years of quitting - **Radon Mitigation**: Home testing and ventilation systems - **Occupational Protections**: Respirators in high-risk industries - **Air Quality Management**: HEPA filters in polluted areas ### Secondary Prevention (Screening) | Screening Method | Target Population | Frequency | Effectiveness | |------------------|-------------------|-----------|--------------| | Low-dose CT scan | Smokers 50-80 yrs with 20 pack-year history | Annual | 20% mortality reduction | | Liquid Biopsy | High-risk non-smokers with family history | Biannual | Experimental | ### Tertiary Prevention - **Pulmonary Rehabilitation**: Post-surgical recovery - **Targeted Therapies**: For EGFR/ALK mutation-positive tumors - **Immunotherapy**: PD-1/PD-L1 inhibitors for advanced NSCLC