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Diagnosing Lung Cancer

A series of tests are necessary to diagnose lung cancer. Further testing then identify the type and stage of the cancer, which help determine treatment options.

Chest x-rays have been shown ineffective to screen for lung cancer but for some, a problem in the lungs may first be identified by chest x-ray.

  • Chest X-Ray. Uses small amounts of radiation to take a two-dimensional picture of the inside of the chest cavity. Some tumors may be seen by x-ray, while others may be too small or hidden behind bone and will not be picked up in an x-ray. Chest x-rays are valuable tools for diagnosing diseases such as pneumonia.

If something of concern is found on an x-ray, a CT scan is typically ordered. For some, the CT scan is the first test in the diagnostic process. 

  • Computed Tomography (CT). Known as CT or CAT scans, this test gives a more detailed picture than chest x-rays. CT scans can detect extremely small tumors and can give three-dimensional imaging of the tumor. CTs can also help determine if the tumor has spread to lymph nodes surrounding the lungs.

To determine if a problem area is indeed lung cancer, a biopsy must be performed.

  • Biopsy. Confirms the presence of cancer. Small pieces of suspicious tissue or fluids are removed from the body and examined under a microscope by a doctor called a pathologist. The procedure not only confirms the presence of cancer but typically determines the kind of lung cancer as well. Biopsies are often done on a tumor in the lung but suspicious tissue from the chest lining and lymph nodes or fluid in the chest cavity or lungs may also be biopsied.  

There are a number of ways that tissue or fluid can be obtained by biopsy. The type of procedure is typically determined by the size of the tumor and where it is located in the lungs.

  • Needle Biopsy or Needle Aspiration. A hollow biopsy needle is inserted through the skin to draw out tissue or fluid for testing. Different types of needles are used and the procedure is usually done with the aid of imaging tests such as CT, fluoroscopy, ultrasound, or MRI.  
  • Bronchoscopy. A thin, flexible tube (bronchoscope) is inserted into the lungs through the nose or mouth.  A small camera is used to look directly into the airways and the lungs. A needle inserted into the bronchoscope can take samples of the tumor or fluid for testing. A rigid bronchoscopy uses a metal tube in the same way.
  • Autofluorescence Bronchoscopy. A bronchoscope is inserted into the lungs through the nose or mouth. A special light is used with a camera, which captures live color video which is viewed on a monitor. Under this light, abnormal/pre-cancerous tissue appears in a different color than normal tissue. This procedure gives more information than a traditional brochoscopy. Tissue samples can also be removed for testing.  
  • Endobronchial Ultrasound (EBUS). A type of ultrasound (high frequency sound waves) combined with a bronchoscope and inserted through the mouth. This procedure allows for better examination of the lymph nodes and other structures in the center of the chest to see if cancer has spread. Tissue samples can also be removed for testing.
  • Mediastinoscopy. A surgical procedure in which an incision made just above the breastbone allows a device with a camera attached to pass into the middle of the chest (mediastinum) to see if cancer is present there and to check central lymph nodes for cancer. Tissue samples can also be removed for testing.
  • Thoracentesis. A hollow needle is used to draw fluid that has collected between the lungs and the chest wall. The fluid is then tested to see if it contains cancer cells.
  • Thoracoscopy. A surgical procedure in which an incision in the chest wall allows a device with a camera attached to be inserted into the lungs so the lungs and surrounding area can be explored. Tissue samples can also be removed for testing.

Surgery can also be used to obtain tissue for a biopsy.   

Other tests used to stage lung cancer at diagnosis include:

  • Magnetic Resonance Imaging (MRI). A type of imaging scan that uses magnetic fields to create clear images of body parts, including tissues, muscles, nerves and bones. The images produced show the presence of tumors. MRI is the most sensitive test used to check for the spread of lung cancer to the brain.  
  • Positron Emission Tomography (PET). A type of imaging scan that is used to tell if lung cancer has spread to other parts of the body. Cells use sugar (glucose) for energy to function and cancer usually uses more than other cells or tissues. A special sugar solution is injected into the body through a vein. The solution collects where there is a lot of activity and “lights up” on the scan. The areas on the scan where a lot of the solution builds up shows where cancer may be present. 

Some machines combine PET and CT procedures into one. PET/CT scans tend to take less time to administer and provide a more accurate picture of what is going on inside the body.