Diagnosis
If you have symptoms of lung cancer, your doctor will conduct a physical exam and take your medical history to determine what might be causing them. If your doctor thinks lung cancer might be present, he will most likely order a chest X-ray or CT scan of the chest and upper abdomen to look for any abnormal areas in the lungs.
Chest X-Ray
A chest X-ray uses electromagnetic waves to create pictures of the inside of your body. Your doctor will order a chest X-ray to check any suspicious areas in your lungs. If your chest X-ray looks suspicious in any way, your doctor will order additional tests.
Computed tomography (CT) scan
A CT scan can show the exact location, size, and shape of a tumor in the lungs, and can also show cancer in the lymph nodes and other parts of the body including the liver and the adrenal glands. For a CT scan, you lie flat on a table while a machine rotates around your body and takes pictures, producing detailed cross-sectional images of your body.
Low-dose Computed Tomography (LDCT) scan
Doctors use low-dose CT scans to screen patients who are at high risk for lung cancer for screening purposes. Low-dose CT scans use much lower amounts of radiation than standard CT scans. High-risk patients include people over the age of 50, people who have smoked a pack a day for at least 20 years, or patients who also have additional risk factors.
Biopsy
If your chest X-ray or other imaging tests show an abnormality or suspicious area, your doctor may need to conduct a biopsy to know for sure if it is cancer. During a biopsy your doctor will remove a tissue sample from your lungs and have it examined under a microscope for any signs of lung cancer. Your doctor may perform the following biopsy procedures to diagnose lung cancer:
Sputum Cytology
Your doctor will take a sample of mucus coughed up from your lungs and have it examined under a microscope for any signs of lung cancer. This test can help find squamous cell carcinomas that don't form as deeply in the lungs.
Bronchoscopy
Your doctor inserts a flexible, narrow tube with a camera and light on the end (bronchoscope) into your nose or mouth and guides it to your lungs. Your doctor uses this device to examine the lungs and remove suspicious tissue samples for a biopsy.
Endobronchial ultrasound (EBUS)
For this test, the doctor uses a bronchoscope with an ultrasound device at the end of the tube to examine the windpipe and nearby lymph nodes. The device sends out high-energy sound waves and allows the doctor to determine if the cancer has invaded any lymph nodes or nearby structures. A needle biopsy can be taken of suspicious areas. The doctor may use the endobronchial ultrasound to guide the needle to the tumor.
Thoracentesis
For this procedure, a small hollow needle is inserted between your ribs to drain fluid from around the lungs. Your doctor will have this fluid examined under a microscope to determine whether it is caused by cancer or another condition.
Fine Needle Aspiration (FNA) biopsy
Your doctor uses a fine needle connected to a syringe to extract a tissue sample from a suspicious area usually using CT scan guidance. This procedure makes it easier to get biopsy samples from the outer layers of the lungs that are hard to reach with a bronchoscopy.
Additional Tests
Your doctor may also order the following imaging tests and diagnostic procedures to check for signs for cancer that may have spread and determine the stage of your disease.
Magnetic Resonance Imaging (MRI) scan
Magnetic resonance imaging (MRI) uses radio waves and a strong magnet to create clear and detailed pictures of body parts. The body absorbs radio waves, which are then released in a certain pattern. This pattern is translated by a computer in order to show "slices" of the body. Doctors commonly use MRIs to check the brain and spinal cord for any signs of disease that may have spread to other organs (metastasis).
Positron Emission Tomography (PET) Scan
For a PET scan, the doctor injects a radioactive sugar substance into the patient's bloodstream. This substance collects in malignant (cancerous) cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the exact location of cancer in the patient's body. The PET scan is a sugar metabolism scan to identify areas of high metabolism. Cancers can have higher metabolism than normal tissues. Sometimes other areas of infection, inflammation, or healing fractures can be identified by a PET scan as well. The picture is not as detailed as a CT or MRI scan, but can show the whole body and help spot areas of cancer spread.
Bone Scan
A bone scan uses a radioactive substance to identify cancerous tissues in the bones. A bone scan provides a picture of all of the bones in the body, and allows doctors to detect small areas of cancer not visible on standard X-rays. The radioactive substance collects in these areas and illuminates them on the skeletal X-ray.
Mediastinoscopy
Your doctor may perform this procedure to look more closely at the area between your lungs often if EBUS is not successful. Your doctor makes an incision in the front of your neck and passes a lighted tube behind your breast bone, next to your windpipe, and into the area between your lungs to examine and biopsy the lymph nodes near your windpipe.
Pulmonary Function Test (PFT)
Your doctor may perform a PFT after your lung cancer is diagnosed to get a sense of your respiratory health. This is not a diagnostic or staging test, but it is important to know how strong your lungs are, how well your lungs are exchanging oxygen and carbon dioxide, and if you will be able to tolerate surgery to remove part of your lungs.
