Lung Cancer Diagnosis
There are many tests used to detect, diagnose, and stage lung cancer. Tests are also used to see if cancer has spread (metastasized) to other part of the body from where it started.
For most types of cancer, a biopsy is the only sure way for the doctor to know if an area of the body has cancer. A biopsy is a procedure in which the doctor takes a sample of tissue for testing in a laboratory. In the case that a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.
Doctors will take certain factors into consideration when choosing a diagnostic test. These factors include:
- The type of cancer suspected, size and location of it
- Signs and symptoms
- Age and general health
- Earlier medical test results
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):
- Chest x-ray: An x-ray of the organs and bones inside the chest.
- CT Scan (CAT scan) of the brain, chest, and abdomen: These are a series of detailed images of the inside of the body, taken from multiple angles. The images are then compiled by a computer linked to an x-ray machine. A dye is either injected into a vein or swallowed to show the organs or tissues more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- PET Scan (positron emission tomography scan): A tiny amount of radioactive glucose (sugar) is injected into a vein to find malignant tumor cells in the body. The PET scanner rotates around the body and makes an image of where glucose is being used in the body. Malignant tumor cells show up brighter in the image because they are more active and take up more glucose than normal cells do.
- Sputum Cytology: A microscope is used to check for cancer cells in the sputum (mucus coughed up from the lungs).
- Bronchoscopy: A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It 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 to check under a microscope for signs of cancer.
- 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. 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 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.
- 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. In some cases, this procedure is used to remove part of the esophagus or lung. If certain tissues, organs, or lymph nodes can’t be reached, a thoracotomy may involve a larger incision between the ribs to open the chest.
- Thoracentesis: A procedure that uses a needle to remove fluid from the space between the lining of the chest and the lung. A pathologist will look at the fluid under a microscope to find cancer cells.
- Laboratory tests: Includes testing samples of tissue, blood, urine, or other substances in the body. These tests help to diagnose a disease, plan and review treatment, or monitor a disease over time.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the brain. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Radionuclide bone scan: This procedure is used to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream, where it collects in the bones and is detected by a scanner.
- Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography. EUS may be used to guide fine needle aspiration (FNA) biopsy of the lung, lymph nodes, or other areas.