One fourth of all people with lung cancer have no symptoms when the cancer is diagnosed. These cancers are usually identified incidentally when a chest X-ray is performed for another reason. The other three-fourths of people develop some symptoms. The symptoms are due to direct effects of the primary tumor; to effects of cancer spread to other parts of the body (metastases); or to disturbances of hormones, blood, or other systems.
Symptoms of lung cancer include cough, coughing up blood or rusty-colored phlegm, fatigue, unexplained weight loss, recurrent respiratory infections, hoarseness, new wheezing, and shortness of breath.