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Lung Cancer
Diagnosis

To help find the cause of symptoms, your doctor will evaluate your medical history, smoking history, exposure to environmental and occupational substances, and family history of cancer. Your doctor will perform a physical exam and may recommend a chest X-ray, computed tomography (CT) scan and other tests.

If lung cancer is suspected, sputum cytology — the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs — is a simple test that may be useful in detecting lung cancer. To confirm the presence of lung cancer, your doctor must examine tissue. A biopsy — the removal of a small sample of tissue for examination under a microscope by a pathologist — can determine if you have cancer. A number of procedures may be used to obtain this tissue:

  • Bronchoscopy — A bronchoscope, a thin, lighted tube, is put into your mouth or nose and down your windpipe to look into the breathing passages. Through this tube, your doctor can collect cells or small samples of tissue.
  • Needle Aspiration — A needle is inserted through the chest into the tumor to remove a sample of tissue.
  • Computerized Tomography (CT)-Guided Biopsy — A computerized axial tomography scan is more commonly known by its abbreviated name, CAT scan or CT scan. It is an X-ray procedure that combines many X-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body.

    A large, donut-shaped X-ray machine takes images at many different angles in the chest. These images are processed by a computer to create cross-sectional pictures. In each of these pictures the body is seen as an X-ray "slice" of the body, which is recorded on film. This recorded image is called a tomogram.

    A CT scan is used to define normal and abnormal structures in the body. During a CT-guided biopsy, the scan is used to help the doctor accurately guide the needle into the suspected tumor so a sample can be removed.
  • Thoracentesis — This is the removal of fluid in the chest, which can be done under the guidance of ultrasound or CT guidance (see above). Using a needle, the doctor removes a sample of the fluid that surrounds the lungs to check for cancer cells.

Staging

If the diagnosis is cancer, your doctor will determine the stage or extent of the disease. Staging is done to find out whether cancer has spread and, if so, to what parts of the body. Lung cancer often spreads to the brain, bone, liver and adrenal gland. Knowing the stage of the disease will help your doctor plan treatment. Some tests used to determine if cancer has spread include:

  • Computerized Axial Tomography (CAT or CT) Scan — A computerized axial tomography scan is more commonly known as a CAT or CT scan. It is a X-ray procedure that combines many X-ray images with the aid of a computer to generate cross-sectional views and, if needed, three-dimensional images of the internal organs and structures of the body. A large, donut-shaped X-ray machine takes images at many different angles in the body. These images are processed by a computer to produce cross-sectional pictures. In each of these pictures the body is seen as an X-ray "slice" of the body, recorded on a film. This recorded image is called a tomogram. A CT scan is used to define normal and abnormal structures in the body.
  • Magnetic Resonance Imaging (MRI) — MRI uses radio waves, a powerful electromagnet and a computer to view detailed areas of the body, including the brain.
  • Bone Scan — A bone scan can show if cancer has spread to the bones. A small amount of radioactive substance is injected into a vein. It travels through the bloodstream and collects in areas of abnormal bone growth. An instrument called a scanner measures the radioactivity levels in these areas and records them on X-ray film.

    There are no dietary restrictions for this test. The patient usually is given an injection of radioactive tracer that is "tagged" to a calcium-like material about three hours before the scan to give the calcium time to circulate and be taken up by the bone. The patient is then allowed to leave and return to the scanning facility approximately three hours later to complete the scan.
  • Positron Emission Tomography (PET) Scan — This imaging technique monitors metabolic, or biochemical, activity in the brain and other organs by tracking the movement and concentration of a radioactive tracer injected into the bloodstream. The technique uses special computerized imaging equipment and rings of detectors surrounding the patient to record gamma radiation produced when positrons (positively-charged particles) emitted by the tracer collide with electrons. It produces images that can be used to measure many vital processes, including glucose metabolism, blood flow and perfusion, and oxygen utilization. With these images, your doctor can identify normal and abnormal states.
  • Mediastinoscopy and Mediastinotomy — A mediastinoscopy can help show if cancer has spread to the lymph nodes in the chest. Using a lighted viewing instrument, called a scope, your doctor examines the center of the chest (mediastinum) and nearby lymph nodes. In mediastinoscopy, the scope is inserted through a small incision in the neck; in mediastinotomy, the incision is made in the chest. In both procedures, the scope is also used to remove a tissue sample. A general anesthetic is given before this procedure. Usually, this procedure doesn't require an overnight stay in the hospital.

Reviewed by health care specialists at UCSF Medical Center.