Common tests to evaluate lung cancer include the following.
A biopsy is the removal of a small amount of tissue for examination under a microscope. The sample removed from the biopsy is analyzed by a pathologist. If cancer cells are present, the pathologist will determine if it is small lung cancer or non-small cell lung cancer based on its appearance under the microscope.
If there is reason to suspect lung cancer, the doctor may ask a person to cough up some phlegm so it can be examined under the microscope. A pathologist can find cancer cells mixed in with the mucus.
In this procedure, the doctor passes a thin, flexible tube with a light on the end into the mouth or nose down through the main windpipe, and into the breathing passages of the lungs. A surgeon or pulmonologist, a doctor who specializes in the diagnosis and treatment of lung disease, may perform this procedure. The tube lets the doctor see inside the lungs. Tiny tools inside the tube can take samples of fluid or tissue, so the pathologist can examine them. Patients are given mild anesthesia during a bronchoscopy.
After numbing the skin, a radiologist inserts a small needle through the chest and directly into the lung tumor. The doctor uses the needle to aspirate, or suck out, a small sample of tissue for testing. Often, the radiologist uses a chest CT scan or special x-ray machine called a fluoroscope to guide the needle.
Bone Marrow Biopsy
Doctors sometimes perform this test in patients with small cell lung cancer. The doctor uses a local anesthetic to numb the area and a special needle to remove a tiny piece of bone, typically from the hip bone, to determine whether small cell cancer is present within the bones.
After numbing the area, a needle is inserted through the chest wall and into the space between the lung and the wall of the chest where fluid can collect. The fluid is taken out and examined for cancer cells.
This procedure is performed in an operating room with the help of general anesthesia, which allows the person to sleep during the procedure. A surgeon then makes an incision into the chest, examines the lung directly and takes tissue samples for testing.
Thoracoscopy: Through a small cut in the skin of the chest wall, a surgeon can insert a special instrument and a small video camera to assist in the examination of the inside of the chest. Patients require general anesthesia, but recovery time may be shorter than with a thoracotomy given the smaller incisions. This procedure may also be referred to as VATS (video-assisted thoracoscopic surgery).
A surgeon examines and takes a sample of the lymph glands in the center of the chest underneath the breastbone by making a small incision at the top of the breastbone. This procedure requires general anesthesia.
CT and Magnetic Resonance Imaging (MRI) Scans
These scans produce images that allow doctors to see the size and location of lung tumors and/or lung cancer metastases. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI scanning is imprecise when used to image a structure that is moving, like your lungs. For that reason, the MRI scan is rarely used to study the lungs themselves, but is often used for imaging of the brain.
Positron Emission Tomography (PET) Scan
In a PET scan, small amounts of radioactive sugar molecules are injected into the body. Lung cancer cells absorb sugar more quickly than normal cells, so they light up on the PET scan. PET scans are often used to complement information gathered from CT scan, MRI and physical examination. Normal tissues, such as the heart and brain, and benign tumors can also take up sugar quickly. Specialists in nuclear medicine help your doctor interpret PET scans. There are some cancerous lung tumors that do not take up sugar faster than normal tissues.
A bone scan uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Bone scans are often used in combination with information gathered from a CT scan, an MRI, regular x-rays and a physical examination.