Lung Cancer

Lung cancer begins when cells in the lungs start growing uncontrollably. It is the leading cause of cancer deaths but is increasingly treatable, especially when detected early. **Main Types:** - **Non-Small Cell Lung Cancer (NSCLC):** About 80-85% of cases. Includes adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Generally grows more slowly. - **Small Cell Lung Cancer (SCLC):** About 10-15% of cases. More aggressive, usually related to heavy smoking. Often responds well initially to chemotherapy but frequently returns. **Stages:** - Stage I: Cancer only in the lung, not spread to lymph nodes - Stage II: Cancer in lung and nearby lymph nodes - Stage III: Cancer spread to lymph nodes in the middle of chest - Stage IV: Cancer spread to both lungs, fluid around lungs, or distant organs **Key Advances:** Targeted therapies and immunotherapies have transformed treatment for many patients, offering better outcomes with fewer side effects than traditional chemotherapy.

**Smoking:** Cigarette smoke contains more than 7,000 chemicals, many carcinogenic. These damage lung cell DNA, leading to mutations that cause cancer. Risk increases with duration and amount smoked. **Radon:** This naturally occurring radioactive gas seeps from soil into homes. It's the leading cause of lung cancer in non-smokers. Testing your home is the only way to know if radon levels are elevated. **Genetic Factors:** Certain genetic mutations (EGFR, ALK, ROS1, BRAF) drive cancer growth. These are more common in non-smokers and young people with lung cancer. Targeted therapies can specifically attack these mutations. **Environmental/Occupational:** Asbestos, especially combined with smoking, greatly increases risk. Various industrial exposures contribute to some lung cancers. **Why Non-Smokers Get Lung Cancer:** While smoking causes most cases, 10-20% of lung cancers occur in never-smokers. Causes include radon, secondhand smoke, genetic factors, and sometimes unknown reasons.