To help find the cause of symptoms, the doctor evaluates a person's medical history, lifestyle habits, exposure to environmental and occupational substances, and a family history of cancer. The doctor also performs a physical exam and may order a chest x-ray and other tests.

If lung cancer is suspected, sputum cytology (the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs) is a simple test that may be useful in detecting lung cancer. To confirm the presence of lung cancer, the doctor must examine tissue from the lung.

Common methods of diagnosis
A biopsy -- the removal of a small sample of tissue for examination under a microscope by a pathologist -- can show whether a person has cancer. A number of procedures may be used to obtain this tissue:

• Bone scan - A bone scan, one type of radionuclide scanning, can show whether cancer has spread to the bones. A small amount of radioactive substance is injected into a vein. It travels through the bloodstream and collects in areas of abnormal bone growth. An instrument called a scanner measures the radioactivity levels in these areas and records them on x-ray film.

• Bronchoscopy - Looking at the lungs through a hollow, flexible tube knkown as a bronchoscope. The tube is passed through the nose and down the throat into the main airway of the lungs. A biopsy can then be obtained through the bronchoscope if abnormal tissues or tumors are found.
  
  

• Chest examination: Looking at the chest and listening to the lungs with a stethoscope to detect abnormal breathing sounds or patterns.
  
  

• Chest X-ray: Taking an x-ray of the lungs to identify abnormal growths.
  
  

• CT scan: Taking a two-dimensional scan from a series of X-ray images. These sensitive scans reveal much more detail than x-rays.

• Mediastinoscopy - A mediastinoscopy can help show whether the cancer has spread to the lymph nodes in the chest. Using a lighted viewing instrument, called a scope, the doctor examines the center of the chest, or mediastinum, and nearby lymph nodes. In mediastinoscopy, the scope is inserted through a small incision in the neck; in mediastinotomy, the incision is made in the chest. In either procedure, the scope is also used to remove a tissue sample. The patient receives a general anesthetic.

• MRI: Similar to a CT scan, MRIs use a magnetic field in place of X-rays to produce an image.

• Needle aspiration - A needle is inserted through the chest into the tumor to remove a sample of tissue.
  
  

• PET scan: Traces the way the body cells react to sugar as a means of finding cancerous tumors.
  
  

• Physical examination: Looking for signs of swollen lymph nodes in the neck or collarbone area, as well as checking the overall state of health.

• Radionuclide scanning - Scanning can show whether cancer has spread to other organs, such as the liver. The patient swallows or receives an injection of a mildly radioactive substance. A machine (scanner) measures and records the level of radioactivity in certain organs to reveal abnormal areas.
  
  

• Sputum cytology - Phlegm from the lungs is examined under a microscope to check for cancerous cells.
  
  

• Thoracentesis - Using a needle, the doctor removes a sample of the fluid that surrounds the lungs to check for cancer cells.

• Thoracotomy - Surgery to open the chest is sometimes needed to diagnose lung cancer. This procedure is a major operation performed in a hospital.

If the diagnosis is cancer, the doctor will also want to learn the stage, or extent, of the disease. Staging is done to find out whether the cancer has spread and, if so, to what parts of the body. Lung cancer often spreads to the brain or bones.

Knowing the stage of the disease helps the doctor develop a treatment plan. Some tests used to determine whether the cancer has spread include:

See also

• Introduction
• Causes and risk factors
• Lung cancer - treatment options
• Support