Lung Cancer Diagnosis
There are multiple tests used to detect, diagnose, and stage lung cancer. The tests used with each patient will vary based on the type and whether it’s suspected that the cancer has spread (metastasized) outside of the lungs. Factors that may influence which tests to be used include:
- Size, location, and type of lung cancer suspected
- Your signs and symptoms
- Your age and general health
- The results of earlier medical tests
Lung Biopsy / Tissue Sampling
Most lung cancer patients will have a biopsy of the lungs. This procedure collects a sample of lung tissue to be tested in a lab for cancerous cells. Various procedures can be used. Your oncologist and cancer surgeon will discuss what is best in your situation. Some of the types of tissue tests that may be performed include:
- Fine-needle aspiration (FNA) biopsy of the lung: A CT scan, ultrasound, or other imaging procedure is used to locate the abnormal tissue or fluid in the lung, and then a small incision may be made in the skin where the biopsy needle is inserted into the abnormal tissue or fluid. A sample is removed with the needle and sent to the laboratory. A pathologist then views the sample under a microscope to look for cancer cells. A chest x-ray is performed afterward to ensure that no air is leaking from the lung into the chest.
- Bronchoscopy: Uses a bronchoscope, which is a thin, tube-like instrument with a light and a lens for viewing, that is inserted through the nose or mouth into the trachea and lungs to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.
If a biopsy is not possible, your doctor may use other tests that will help make a diagnosis.
Other Lung Cancer Diagnostic Tests
In addition to a physical examination and discussion about your family health history, the following tests may be used to diagnose and stage both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC):
Lung Imaging Tests
- CT Scan (CAT scan) of the brain, chest, and abdomen: A series of detailed pictures of areas inside the body, taken from different angles. The images are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- PET Scan (positron emission tomography scan): A small amount of radioactive glucose (sugar) is injected into a vein, which aims to find malignant tumor cells in the body. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than do normal cells.
- MRI Scan: This type of imagery allows the oncology team to identify areas where the lung cancer may have spread or to measure a tumor’s size. Because MRIs don’t work as well for body parts that are moving, like the lungs, it’s not normally used as a primary imaging tool for lung cancer diagnosis, unless metastasis is suspected.
- Thoracoscopy: A surgical procedure to check for abnormal areas by looking at the organs inside the chest. A thoracoscope is a thin, tube-like instrument with a light and a lens for viewing. Typically, an incision (cut) is made between two ribs to insert a thoracoscope into the chest for viewing or for using a tool to remove tissue or lymph node samples that are then checked under a microscope for signs of cancer.
- Thoracentesis is using a needle to remove fluid from the space between the lining of the chest and the lung. A pathologist then views the fluid under a microscope to look for cancer cells.
- Mediastinoscopy: A procedure in which a sample of the lymph nodes in the center of the chest underneath the breastbone is taken by making a small incision at the top of the breastbone. This procedure also requires general anesthesia and is done in an operating room.
- Thoracotomy: A procedure in which the surgeon makes an incision in the chest to examine the lung directly and take tissue samples for testing. A thoracotomy is the procedure surgeons most often use to remove a lung tumor completely.
Lab and Bone tests
- Laboratory tests: Includes testing samples of tissue, blood, urine, or other substances in the body. These tests help to diagnose disease, plan and check treatment, or monitor the disease over time.
- Sputum Cytology: A microscope is used to check for cancer cells in the sputum (mucus coughed up from the lungs).
- Radionuclide bone scan: Used to check if there are rapidly dividing cells, such as cancer cells, in the bones. A minimal amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.