Small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung.The lungs are a pair of cone-shaped breathing organs that are found in the chest. The lungs bring oxygen into the body when you breathe in and take out carbon dioxide when you breathe out. Each lung has sections called lobes. The left lung has two lobes. The right lung, which is slightly larger, has three. A thin membrane called the pleura surrounds the lungs. Two tubes called bronchi lead from the trachea (windpipe) to the right and left lungs. The bronchi are sometimes also affected by lung cancer. Small tubes called bronchioles and tiny air sacs called alveoli make up the inside of the lungs.
There are two types of lung cancer: small cell lung cancer and non-small cell lung cancer. This summary is about small cell lung cancer and its treatment. See the following PDQ summaries for more information about lung cancer:
- Unusual Cancers of Childhood
- Lung Cancer Prevention
- Lung Cancer Screening
There are two main types of small cell lung cancer.These two types include many different types of cells. The cancer cells of each type grow and spread in different ways. The types of small cell lung cancer are named for the kinds of cells found in the cancer and how the cells look when viewed under a microscope:
- Combined small cell carcinoma.
Smoking increases the risk of small cell lung cancer.Smoking cigarettes, pipes, or cigars is the most common cause of lung cancer. The earlier in life a person starts smoking, the more often a person smokes, and the more years a person smokes, the greater the risk of lung cancer. If a person has stopped smoking, the risk becomes lower as the years pass. Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk to your doctor if you think you may be at risk. Risk factors for small cell lung cancer include:
- Being exposed to secondhand smoke.
- Having a family history of lung cancer.
- Being treated with radiation therapy to the breast or chest.
- Being exposed to asbestos, chromium, nickel, arsenic, soot, or tar in the workplace.
- Being exposed to radon in the home or workplace.
- Living where there is air pollution.
- Being infected with the human immunodeficiency virus (HIV).
- Using beta carotene supplements and being a heavy smoker.
Signs and symptoms of small cell lung cancer include coughing, shortness of breath, and chest pain.These and other signs and symptoms may be caused by small cell lung cancer or by other conditions. Check with your doctor if you have any of the following:
- Chest discomfort or pain.
- A cough that doesn’t go away or gets worse over time.
- Trouble breathing.
- Blood in sputum (mucus coughed up from the lungs).
- Trouble swallowing.
- Loss of appetite.
- Weight loss for no known reason.
- Feeling very tired.
- Swelling in the face and/or veins in the neck.
Tests and procedures that examine the lungs are used to detect (find), diagnose, and stage small cell lung cancer.The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits, including smoking, and past jobs, illnesses, and treatments will also be taken.
- Laboratory tests: Medical procedures that test 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.
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
- CT scan (CAT scan) of the brain, chest, and abdomen: A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures 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 up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- Light and electron microscopy: A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
- Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.