Overview
Definition
Malignant neoplasm of the lung arising from the respiratory epithelium. Broadly divided into Non-Small Cell (NSCLC) and Small Cell (SCLC).
Epidemiology
The leading cause of cancer-related death worldwide in both men and women.
Etiology & Risk Factors
- Tobacco smoking (accounts for 85-90% of cases)
- Radon gas exposure
- Asbestos exposure (synergistic with smoking)
- Air pollution
- Genetics
Clinical Symptoms
- Chronic, worsening cough
- Hemoptysis
- Unintended weight loss
- Chest pain
- Hoarseness (recurrent laryngeal nerve involvement)
Clinical Approach
Diagnosis
- Chest CT with contrast (Initial imaging to identify nodule/mass)
- Biopsy (Bronchoscopy for central lesions, CT-guided transthoracic needle biopsy for peripheral lesions) for definitive tissue diagnosis
- PET-CT and Brain MRI for staging
Management
- NSCLC (Adenocarcinoma, Squamous Cell, Large Cell): Surgery is preferred for early stages (I and II). Radiation and Chemotherapy (or Immunotherapy/Targeted therapy like EGFR inhibitors) for advanced stages.
- SCLC: Highly aggressive and usually systemic at diagnosis. Chemotherapy (Platinum + Etoposide) and Radiation. Prophylactic cranial irradiation (PCI) is often indicated.
Complications
- Metastasis (Brain, Bone, Liver, Adrenals)
- Superior Vena Cava (SVC) Syndrome
- Paraneoplastic Syndromes (SIADH or Cushing's in SCLC; Hypercalcemia in Squamous Cell)