Lung cancer is cancer that forms in the tissues of the lung, usually in the cells lining the air passages. There are two main types of lung cancer – small cell lung cancer and non-small cell lung cancer:
Small cell – this variety progresses more quickly and is more likely to spread beyond the lungs.
Non-small cell – is the more common of the two. It is slower-growing and less likely to spread to other organs of the body.
How is lung cancer diagnosed?
When your physician suspects lung cancer, he or she may recommend a series of diagnostic tests. These tests will vary depending on the symptoms presented.
First, your doctor may order a chest X-ray, CT scan, or other non-invasive procedure. If these tests indicate possible lung cancer, a sputum cytology (a test which examines mucus) may also be recommended. To confirm the presence of lung cancer, a biopsy (which is the removal of a small sample of tissue for examination under a microscope) must be performed.
Your doctor may order one or more of the following tests to collect samples:
Bronchoscopy – your physician inserts a bronchoscope (a thin, lighted tube) through the nose or mouth into the lungs. This allows an examination of the lungs and the air passages that lead to them.
The doctor may also take a sample of cells through this tube. This is an outpatient procedure. The back of the throat is numbed with a local anesthetic spray or inhalation. In most cases, intravenous (IV) sedative medications are given before the procedure to induce drowsiness and relaxation. Patients are partially alert during the procedure.
In some cases, samples of tissue and fluid are taken using devices connected to the bronchoscope. Other procedures can be performed during the bronchoscopy, including removing foreign objects or delivering radiation therapy directly to the lungs. In general, the patient should not feel pain. Patients may also be asked to hold their breath for periods of time during parts of the procedure.
Core-needle aspiration – your physician uses a large bore needle to remove tissue or fluid from the lung.
Sometimes a CT scan or other imaging method is used to guide the needle to a lung tumor. This procedure is an advance over the fine-needle aspiration used at most other area hospitals because it collects more tissue for testing, yielding better results and reducing the need for retesting. The procedure uses a local anesthetic. It is about as painful as drawing blood from the arm for laboratory testing. Although not painless, any associated discomfort is usually minimal.
Mediastinoscopy – a lighted tube is inserted under the breast bone through an incision at the lower part of the neck and used to obtain tissue samples from lymph nodes around the airways. The tissue can then be tested for the presence of cancer cells.