Catching lung cancer before you notice symptoms (see Signs and Symptoms) is difficult and often leads to a delayed diagnosis. Currently there are no definite tests that are proven to find cancer at the early stage. However, studies are underway to test the usefulness of spiral CT scan and DNA testing in early detection in high-risk people.
Unfortunately 40 % of all lung cancers are diagnosed when the cancer has spread (metastasized) to other parts of the body. Five-year survival rates are directly related to how much the cancer has grown/spread.