Lung cancer is a type of cancer that begins in lung tissue. The earliest stages of lung cancer don't normally have symptoms, and the cancer may take years to grow. The cancer begins showing signs and symptoms as it invades organs and tissues nearby and metastasizes to other parts of the body. At this point, the cancer is advanced. There are two major types of lung cancer: small cell carcinoma and non-small cell carcinoma.
Lung cancer is the most common cause of cancer death in the United States. The National Cancer Institute estimates there will be about 222,500 new cases of lung cancer and more than 157,000 lung cancer-related deaths by the end of 2010.
Symptoms & Causes
Common symptoms of lung cancer can include:
- persistent cough
- coughing up blood
- chest pain
- shortness of breath
The leading cause of lung cancer is smoking cigarettes, so many of the symptoms are often dismissed as side effects of smoking. Other causes of lung cancer include exposure to carcinogens—such as asbestos and radon gas—and exposure to secondhand smoke.
Diagnosis & Treatment
Doctors can diagnose lung cancer through several tests including:
- Imaging studies—chest x-ray, computed tomography (CT) scan
- Sputum cytology—microscopic examination of cells produced by coughing
- Tissue biopsy—microscopic examination of a sample of lung tissue
Following diagnosis, a process called staging will determine the extent of the cancer. The stages (0-IV) are based on how far the tumor has grown into the lung tissue, whether it has invaded locally (for example, the lymph nodes, heart, or trachea), or metastasized to other parts of the body (such as the liver, brain, or bones).
Lung cancer is most often treated with one or more of the following:
- targeted drug therapy