Lung Cancer

What it is

Overview

Lung cancer is the number one cancer killer in both men and women in the United States, claiming more lives annually than breast, prostate, and colorectal cancers combined. It begins in the lungs and is primarily divided into two major types: non-small cell lung cancer (NSCLC, ~85% of cases) and small cell lung cancer (SCLC).

Biology

How It Develops

Most lung cancers are caused by carcinogens — primarily tobacco smoke — that repeatedly damage the DNA of cells lining the airways. Over years of cumulative DNA damage, mutations disable tumor suppressor genes (like TP53) and activate oncogenes, leading to unchecked cellular growth. Radon gas, asbestos, air pollution, and genetic factors also play roles.

Warning signs

Symptoms

• —Persistent cough that worsens over time
• —Coughing up blood (hemoptysis)
• —Chest pain, especially when breathing deeply
• —Shortness of breath or wheezing
• —Hoarseness
• —Unintentional weight loss and fatigue
• —Recurring pneumonia or bronchitis

Detection

Diagnosis Methods

• —Low-dose CT scan (LDCT) for high-risk screening
• —Chest X-ray
• —Sputum cytology
• —Bronchoscopy with biopsy
• —CT-guided needle biopsy
• —PET scan and bone scan for staging
• —Molecular/genomic testing (EGFR, ALK, ROS1, PD-L1)

Medical care

Treatment Options

• —Surgery (lobectomy, pneumonectomy)
• —Radiation therapy (including SBRT for early-stage)
• —Chemotherapy
• —Targeted therapy (EGFR, ALK, ROS1 inhibitors)
• —Immunotherapy (checkpoint inhibitors)
• —Combination chemo-immunotherapy

Data

Statistics

Prevention

Risk Factors

• —Cigarette, cigar, and pipe smoking
• —Secondhand smoke exposure
• —Radon gas exposure (leading cause in non-smokers)
• —Asbestos, arsenic, or diesel exhaust exposure
• —Family history of lung cancer
• —Air pollution

Further reading

Resources