The only sure way to know whether cancer is present is to obtain cells from the lungs so that a pathologist can examine them under a microscope. Sometimes, cancer cells can be found in the sputum, a thick fluid that the patient coughs up from deep in the airways. Also, the doctor usually does a biopsy to remove a sample of cells from the lung. A local anesthetic reduces discomfort and gagging, and medicine helps the patient relax as the doctor inserts the tube through the nose or mouth. The doctor can brush or wash cells from the walls of bronchi or snip off small pieces of tissue for study under a microscope.
Needle aspiration is a procedure to remove cells that are hard to reach with the bronchoscope.
After the patient is given a local anesthetic, the doctor inserts a needle through the chest into the tumor to withdraw a small sample of tissue. Most often, the doctor uses fluoroscopy or CT scans to locate the tumor. Using a needle, the doctor removes a sample of the fluid in the pleura and checks it for cancer cells. For this procedure, called thoracentesis, the patient receives a local anesthetic. For some patients, surgery is needed to diagnose lung cancer.