Dr. David Madtes discusses causes, detection, and survival rates of lung cancer. Lung cancer is the leading cause of cancer death in American men and women, responsible for more deaths than breast, pancreatic, prostate and colorectal cancers combined. Ninety percent of lung cancers occur in current or former smokers. Seventy-five percent of lung cancers are detected at advanced stages after growing silently for months or even years before symptoms manifest. By then the cancer has usually spread to other parts of the chest or organs, making treatment difficult and cure almost impossible. Five year survival rates of Stage I lung cancer are 70%, advanced stage is only 5%. This is why screening and early detection is so important. A recent national lung screening trial showed that low-dose CT screening of high risk individuals reduced lung cancer deaths by 20% compared to those who only had chest X-rays.