Key Points for This Section

Small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung. There are three types of small cell lung cancer. Smoking tobacco is the major risk factor for developing small cell lung cancer. Possible signs of small cell lung cancer include coughing, chest pain, and shortness of breath. Tests and procedures that examine the lungs are used to detect (find), diagnose, and stage small cell lung cancer. Certain factors affect prognosis (chance of recovery) and treatment options. For most patients with small cell lung cancer, current treatments do not cure the cancer.

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 within the chest. The lungs bring oxygen into the body when breathing in and take out carbon dioxide when breathing 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 involved in lung cancer. Small tubes called bronchioles and tiny air sacs called alveoli make up the inside of the lungs.

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Anatomy of the respiratory system, showing the trachea and both lungs and their lobes and airways. Lymph nodes and the diaphragm are also shown. Oxygen is inhaled into the lungs and passes through the thin membranes of the alveoli and into the bloodstream (see inset).

There are two types of lung cancer: small cell lung cancer and non-small cell lung cancer. This summary provides information on small cell lung cancer. (See the PDQ summary on Non-Small Cell Lung Cancer Treatment ¹ for more information.)

There are three types of small cell lung cancer.

These three 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:

• Small cell carcinoma (oat cell cancer).
• Mixed small cell/large cell carcinoma.
• Combined small cell carcinoma.

Smoking tobacco is the major risk factor for developing small cell lung cancer.

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. People who think they may be at risk should discuss this with their doctor. Cigarette smoking is the most common cause of lung cancer. Risk factors for small cell lung cancer include:

• Smoking cigarettes, cigars, or pipes now or in the past.
• Being exposed to secondhand smoke.
• Being exposed to asbestos or radon.

Possible signs of small cell lung cancer include coughing, chest pain, and shortness of breath.

These and other symptoms may be caused by small cell lung cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• A cough that doesn’t go away.
• Shortness of breath.
• Chest pain that doesn’t go away.
• Wheezing.
• Coughing up blood.
• Hoarseness.
• Swelling of the face and neck.
• Loss of appetite.
• Weight loss for no known reason.
• Unusual tiredness.

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:

• 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.

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  X-ray of the chest. X-rays are used to take pictures of organs and bones of the chest. X-rays pass through the patient onto film.

• 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 and past illnesses and treatments will also be taken.
• 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.
• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.

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  PET (positron emission tomography) scan. The patient lies on a table that slides through the PET machine. The head rest and white strap help the patient lie still. A small amount of radioactive glucose (sugar) is injected into the patient's vein, and a scanner makes a picture of where the glucose is being used in the body. Cancer cells show up brighter in the picture because they 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 procedure to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope is inserted through the nose or mouth into the trachea and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.

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  Bronchoscopy. A bronchoscope is inserted through the mouth, trachea, and major bronchi into the lung, to look for abnormal areas. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a cutting tool. Tissue samples may be taken to be checked under a microscope for signs of disease.

• Fine-needle aspiration (FNA) biopsy of the lung: The removal of tissue or fluid from the lung using a thin needle. A CT scan, ultrasound, or other imaging procedure is used to locate the abnormal tissue or fluid in the lung. 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 then views the sample under a microscope to look for cancer cells. A chest x-ray is done after the procedure to make sure no air is leaking from the lung into the chest.

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  Lung biopsy. The patient lies on a table that slides through the computed tomography (CT) machine which takes x-ray pictures of the inside of the body. The x-ray pictures help the doctor see where the abnormal tissue is in the lung. A biopsy needle is inserted through the chest wall and into the area of abnormal lung tissue. A small piece of tissue is removed through the needle and checked under the microscope for signs of cancer.

• Thoracoscopy: A surgical procedure to look at the organs inside the chest to check for abnormal areas. An incision (cut) is made between two ribs, and a thoracoscope is inserted into the chest. A thoracoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue or lymph node samples, which are 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 be done. In this procedure, a larger incision is made between the ribs and the chest is opened.
• Thoracentesis: The removal of fluid from the space between the lining of the chest and the lung, using a needle. A pathologist views the fluid under a microscope to look for cancer cells.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• The stage of the cancer (whether it is in the chest cavity only or has spread to other places in the body).
• The patient’s gender and general health.
• The blood level of lactate dehydrogenase (LDH), a substance found in the blood that may indicate cancer when the level is higher than normal.

For most patients with small cell lung cancer, current treatments do not cure the cancer.

If lung cancer is found, participation in one of the many clinical trials being done to improve treatment should be considered. Clinical trials are taking place in most parts of the country for patients with all stages of small cell lung cancer. Information about ongoing clinical trials is available from NCI Web site ²

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Not normal. An abnormal lesion or growth may be cancerous, premalignant (likely to become cancer), or benign.

Tiny air sacs at the end of the bronchioles in the lungs.

A group of minerals that take the form of tiny fibers. Asbestos has been used as insulation against heat and fire in buildings. Loose asbestos fibers breathed into the lungs can cause several serious diseases, including lung cancer and malignant mesothelioma (cancer found in the lining of the lungs, chest, or abdomen). Asbestos that is swallowed may cause cancer of the gastrointestinal tract.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The large air passages that lead from the trachea (windpipe) to the lungs.

A tiny branch of air tubes in the lungs.

A thin, tube-like instrument used to examine the inside of the trachea, bronchi (air passages that lead to the lungs), and lungs. A bronchoscope has a light and a lens for viewing, and may have a tool to remove tissue.

A procedure that uses a bronchoscope to examine the inside of the trachea, bronchi (air passages that lead to the lungs), and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. The bronchoscope is inserted through the nose or mouth. Bronchoscopy may be used to detect cancer or to perform some treatment procedures.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

A hollow area or hole. It may describe a body cavity (such as the space within the abdomen) or a hole in a tooth caused by decay.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

An x-ray of the structures inside the chest. An x-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.

A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.

The study of cells using a microscope.

The muscular tube through which food passes from the throat to the stomach.

The removal of tissue or fluid with a thin needle for examination under a microscope. Also called FNA biopsy.

Liquid.

A type of sugar; the chief source of energy for living organisms.

A method of producing pictures of areas inside the body.

A cut made in the body to perform surgery.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

One of a group of enzymes found in the blood and other body tissues and involved in energy production in cells. An increased amount of lactate dehydrogenase in the blood may be a sign of tissue damage and some types of cancer or other diseases. Also called lactic acid dehydrogenase and LDH.

Lung cancer in which the cells are large and look abnormal when viewed under a microscope.

A portion of an organ, such as the liver, lung, breast, thyroid, or brain.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

Cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types are diagnosed based on how the cells look under a microscope.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

A very thin layer of tissue that covers a surface.

A thick, slippery fluid made by the membranes that line certain organs of the body, including the nose, mouth, throat, and vagina.

A group of lung cancers that are named for the kinds of cells found in the cancer and how the cells look under a microscope. The three main types of non-small cell lung cancer are squamous cell carcinoma, large cell carcinoma, and adenocarcinoma. Non-small cell lung cancer is the most common kind of lung cancer.

A part of the body that performs a specific function. For example, the heart is an organ.

A colorless, odorless gas. It is needed for animal and plant life. Oxygen that is breathed in enters the blood from the lungs and travels to the tissues.

A doctor who identifies diseases by studying cells and tissues under a microscope.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called positron emission tomography scan.

An exam of the body to check for general signs of disease.

A thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity. It protects and cushions the lungs. This tissue secretes a small amount of fluid that acts as a lubricant, allowing the lungs to move smoothly in the chest cavity while breathing.

The likely outcome or course of a disease; the chance of recovery or recurrence.

Giving off radiation.

A radioactive gas that is released by uranium, a substance found in soil and rock. Breathing in too much radon can damage lung cells and may lead to lung cancer.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

In medicine, an instrument that takes pictures of the inside of the body.

Smoke that comes from the burning of a tobacco product and smoke that is exhaled by smokers. Inhaling secondhand smoke is called involuntary or passive smoking. Also called environmental tobacco smoke and ETS.

An aggressive (fast-growing) cancer that forms in tissues of the lung and can spread to other parts of the body. The cancer cells look small and oval-shaped when looked at under a microscope.

Mucus and other matter brought up from the lungs by coughing.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Removal of fluid from the pleural cavity through a needle inserted between the ribs.

A thin tube-like instrument used to examine the inside of the chest. A thoracoscope has a light and a lens for viewing and may have tool to remove tissue.

Examination of the inside of the chest, using a thoracoscope. A thoracoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.

An operation to open the chest.

A group or layer of cells that work together to perform a specific function.

The airway that leads from the larynx (voice box) to the bronchi (large airways that lead to the lungs). Also called windpipe.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasonography.

A blood vessel that carries blood to the heart from tissues and organs in the body.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.