How is Lung Cancer Diagnosed?
Approximately 5 to 15 percent of lung cancers are discovered in the course of a routine chest x-ray of people with no symptoms. However, more than 50 percent of new lung cancer cases will be diagnosed by the presence of symptoms that indicate cancer spread (metastasis).
Symptoms. Lung cancer symptoms are caused by tumor growth in the lungs, invasion or obstruction of nearby structures, and tumor growth in lymph nodes and in distant sites after cancer spreads through the blood. Symptoms include worsening or chronic cough, shortness of breath, wheezing, coughing up blood, back pain, and weight loss.
Screening. Screening methods include examination of a sputum (spit) sample, chest x-ray, and low-dose spiral computed tomography (CT) lung scanning. A biopsy of the tumor tissue is necessary to confirm a diagnosis of lung cancer. Physical examination, bone scans, brain CT, and bone marrow examination are performed when SCLC is suspected. Positron emission tomography scans are also useful in detecting cancer spread.