For some types of cancer, there are screening tests to detect small tumors while they're still potentially curable. For many cancers, including lung cancer, however, reliable and effective tests for early detection still don't exist. That is one of the reasons that most people diagnosed with lung cancer have advanced disease.
You may not notice any symptoms of lung cancer in its early stages. When early lung cancer does cause symptoms, they're often problems you'd have anyway, particularly if you smoke. For example, some early signs of lung cancer include shortness of breath or a persistent cough.
Most cancers are easier to treat when they are found in their earlier stages and screening tests can often detect cancer before symptoms develop.
You can lower your risk of lung cancer by quitting smoking and avoiding second-hand smoke. Cigarette smoking causes 87 percent of lung cancer deaths.