Overview
Lung cancer is the uncontrolled multiplication of cells beginning in the lungs. It is the most common cause of cancer death in the world. It is the most common cancer in men in our country; about 40,000 new cases are detected each year.
Smoking is the cause of 85% of cases. When diagnosed at an early stage, treatment success increases; however, most cases are detected late.
Types
1. Non-small cell lung cancer (85%):
- Adenocarcinoma (most common)
- Squamous cell carcinoma
- Large cell carcinoma
2. Small cell lung cancer (15%):
- More aggressive
- Spreads rapidly
- Usually smoking-related
Symptoms
No symptoms in early stages. As it progresses:
- Persistent cough (more than 3 weeks)
- Change in cough character
- Bloody sputum (hemoptysis)
- Chest pain
- Shortness of breath
- Wheezing
- Hoarseness
- Unexplained weight loss
- Loss of appetite
- Weakness, fatigue
- Frequent recurring lung infections (pneumonia, bronchitis)
- Bone pain (metastasis)
- Headache, seizures (brain metastasis)
- Difficulty swallowing
- Lymph node enlargement in the neck
- Clubbing of fingers
Causes
Smoking (85%):
- Active smoking (most important cause)
- Secondhand smoke
- Hookah, pipe, cigar
Other causes:
- Radon gas (in homes, underground)
- Asbestos
- Air pollution
- Toxic substances at work (chromium, nickel, arsenic)
- Genetic predisposition
- Previous lung disease (COPD, fibrosis)
- History of radiation therapy
- Family history
Risk Factors
- Smoking (risk proportional to years and quantity)
- Secondhand smoke
- Age (over 55)
- Being male
- Family history
- Occupational exposure
- Air pollution
- Lung diseases
- Radiation
- HIV/AIDS
Complications
- Pleural effusion (fluid in the lungs)
- Bleeding
- Shortness of breath
- Airway obstruction
- Brain, bone, liver metastases
- Superior vena cava syndrome
- Paraneoplastic syndromes
- Pancoast syndrome
Screening Recommendations
For high-risk individuals:
- Ages 50-80
- 20 pack-year smoking history (e.g., 1 pack/day × 20 years)
- Currently smoking or quit within the last 15 years
- Annual low-dose lung CT
When to See a Doctor
- Cough lasting more than 3 weeks
- Bloody sputum
- Shortness of breath
- Chest pain
- Hoarseness (persistent)
- Unexplained weight loss
- Frequent recurring pneumonia
- Regular check-up for anyone with a smoking history
- Follow-up if occupational exposure exists
Diagnosis and Treatment
Diagnosis:
- Chest X-ray
- Chest CT (helps with definitive diagnosis)
- PET-CT (staging)
- Bronchoscopy + biopsy
- Transthoracic needle biopsy
- Mediastinoscopy
- Brain MRI, bone scintigraphy (metastasis)
- Molecular/genetic tests: EGFR, ALK, ROS1, KRAS, PD-L1
- Blood tests
- Pulmonary function tests
Staging:
- Early (Stages 1-2)
- Locally advanced (Stage 3)
- Metastatic (Stage 4)
Treatment:
Non-small cell lung cancer:
1. Surgery:
- Lobectomy, segmentectomy, pneumonectomy
- Mainstay treatment in early stages
- VATS (video-assisted thoracic surgery)
2. Radiotherapy:
- After surgery
- In cases not eligible for surgery
- Stereotactic body radiotherapy (SBRT)
3. Chemotherapy:
- Cisplatin, carboplatin-based
- Pemetrexed, gemcitabine, paclitaxel
4. Targeted therapy:
- EGFR inhibitors: erlotinib, gefitinib, osimertinib
- ALK inhibitors: alectinib, crizotinib
- Personalized based on mutation
5. Immunotherapy:
- Pembrolizumab, nivolumab, atezolizumab
- PD-1/PD-L1 inhibitors
- Revolutionized treatment
Small cell lung cancer:
- Chemotherapy + radiotherapy (main treatment)
- Immunotherapy (addition of atezolizumab)
- Prophylactic cranial radiotherapy (PCI)
Prevention
Quit smoking (most important):
- Never start
- Risk decreases when you quit (50% reduction after 10 years)
- Get smoking cessation support
Other measures:
- Avoid secondhand smoke
- Have radon levels in your home measured
- Use protective equipment for occupational exposure
- Avoid heavily polluted environments
- Eat a vegetable- and fruit-rich diet
- Regular exercise
- Annual CT screening if in high-risk group
- Treat other lung diseases
- More frequent follow-up if family history exists
- Protect from COVID-19 and other infections