Lung cancer is the uncontrolled division of abnormal cells in the lungs. It is the leading cause of cancer deaths in the United States, claiming more lives than cancers of the colon, breast, prostate and ovaries combined.
Smoking is the most common cause of lung cancer, according to the National Institutes of Health (NIH). A naturally occurring gas emitted from rocks and dirt, known as radon, is the second leading cause of lung cancers
Types of Lung Cancers
There are a few types of lung cancers. The two main types are non-small cell lung cancer and small cell lung cancer. Most lung cancers – 80 percent to 90 percent – are non-small cell lung cancers (NSCLCs).
There are three main subtypes of NSCLCs:
- Large cell carcinoma
- Squamous cell carcinoma
Scientists categorize each subtype by the way the cells look under a microscope, as they differ in size, shape and chemical make-up. Doctors group the three subtypes together because the approach to treatment and outlook are similar.
Small cell lung cancer (SCLC) is not as common, accounting for 10 percent to 15 percent of all lung cancers. SCLC frequently begins in the tubes leading to the lungs, known as the bronchi. This type of cancer tends to grow and spread quickly, often spreading to distant parts of the body before detection.
In addition to SCLC and non-small cell lung cancers, other tumors can occur in the lungs. They include adenoid cystic carcinomas, carcinoid tumors, lymphomas, and sarcomas. These lung cancers are rare.
Cancer can also start in other organs and spread to the lungs, but these are not true lung cancers. Cancer that starts in the breast and spreads to the lungs is still breast cancer, for example, and not lung cancer.
Diagnosis and Management
Doctors have a variety of test available to help diagnose lung cancer. Imaging tests, including x-rays and CT scans, can reveal an abnormal mass. Sputum cytology is a laboratory test that looks for the presence of cancer cells. A pulmonologist may use a bronchoscopy, a tube equipped with a camera, to view your lungs and take samples for biopsy.
Lung Cancer Treatment
Treatment usually includes one or more types of therapy, including surgery, chemotherapy, radiation therapy or targeted drug therapy. Surgery involves removal of the tumor, surrounding lung tissue and, in some cases, nearby lymph nodes. Chemotherapy uses drugs and radiation uses high-powered energy beams to kill cancer cells. Targeted drug therapies target specific abnormalities in cancer cells in a way that leaves healthy cells untouched.