Key Points for This Section

Non-small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung. There are several types of non-small cell lung cancer. Smoking can increase the risk of developing non-small cell lung cancer. Possible signs of non-small cell lung cancer include a cough that doesn't go away and shortness of breath. Tests that examine the lungs are used to detect (find), diagnose, and stage non-small cell lung cancer. Certain factors affect prognosis (chance of recovery) and treatment options. For most patients with non-small cell lung cancer, current treatments do not cure the cancer.

Non-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 in the chest. The lungs bring oxygen into the body as you breathe in. They release carbon dioxide, a waste product of the body’s cells, as you breathe out. Each lung has sections called lobes. The left lung has two lobes. The right lung is slightly larger and has three lobes. Two tubes called bronchi lead from the trachea (windpipe) to the right and left lungs. The bronchi are sometimes also involved in lung cancer. Tiny air sacs called alveoli and small tubes called bronchioles 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).

A thin membrane called the pleura covers the outside of each lung and lines the inside wall of the chest cavity. This creates a sac called the pleural cavity. The pleural cavity normally contains a small amount of fluid that helps the lungs move smoothly in the chest when you breathe.

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

There are several types of non-small cell lung cancer.

Each type of non-small cell lung cancer has different kinds of cancer cells. The cancer cells of each type grow and spread in different ways. The types of non-small cell lung cancer are named for the kinds of cells found in the cancer and how the cells look under a microscope:

• Squamous cell carcinoma: Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales. This is also called epidermoid carcinoma.
• Large cell carcinoma: Cancer that may begin in several types of large cells.
• Adenocarcinoma: Cancer that begins in the cells that line the alveoli and make substances such as mucus.

Other less common types of non-small cell lung cancer are: pleomorphic, carcinoid tumor, salivary gland carcinoma, and unclassified carcinoma.

Smoking can increase the risk of developing non-small cell lung cancer.

Smoking cigarettes or cigars is the most common cause of lung cancer. The more years a person smokes, the greater the risk. If a person has stopped smoking, the risk becomes lower as the years pass, but is never completely gone.

Anything that increases a person's chance of developing 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. Risk factors for lung cancer include the following:

• Smoking cigarettes or cigars, now or in the past.
• Being exposed to second-hand smoke.
• Being treated with radiation therapy to the breast or chest.
• Being exposed to asbestos, radon, chromium, arsenic, soot, or tar.
• Living where there is air pollution.

When smoking is combined with other risk factors, the risk of developing lung cancer is increased.

Possible signs of non-small cell lung cancer include a cough that doesn't go away and shortness of breath.

Sometimes lung cancer does not cause any symptoms and is found during a routine chest x-ray. Symptoms may be caused by lung cancer or by other conditions. A doctor should be consulted if any of the following problems occur:

• A cough that doesn’t go away.
• Trouble breathing.
• Chest discomfort.
• Wheezing.
• Streaks of blood in sputum (mucus coughed up from the lungs).
• Hoarseness.
• Loss of appetite.
• Weight loss for no known reason.
• Feeling very tired.

Tests that examine the lungs are used to detect (find), diagnose, and stage non-small cell lung cancer.

Tests and procedures to detect, diagnose, and stage non-small cell lung cancer are often done at the same time. 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.
• 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.

• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the chest, 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 procedure in which a pathologist views a sample of sputum (mucus coughed up from the lungs) under a microscope, to check for cancer cells.
• 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.

• 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.

• 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 (the size of the tumor and whether it is in the lung only or has spread to other places in the body).
• The type of lung cancer.
• Whether there are symptoms such as coughing or trouble breathing.
• The patient’s general health.

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

If lung cancer is found, taking part 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 non-small cell lung cancer. Information about ongoing clinical trials is available from the NCI Web site ².

Glossary Terms

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

Cancer that begins in cells that line certain internal organs and that have gland-like (secretory) properties.

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

A poisonous chemical used to kill weeds and pests. Also used in cancer therapy.

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.

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

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 slow-growing type of tumor usually found in the gastrointestinal system (most often in the appendix), and sometimes in the lungs or other sites. Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome.

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 a 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.

Computed tomography scan. 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 computed tomography scan, computerized tomography, computerized axial tomography scan, and CAT scan.

The process of identifying a disease, such as cancer, from its signs and symptoms.

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."

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.

Positron emission tomography scan. 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.

Occurring in various distinct forms. In terms of cells, having variation in the size and shape of cells or their nuclei.

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 space enclosed by the pleura, which is a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity.

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

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called radiotherapy and irradiation.

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.

A rare cancer that forms in tissues of a salivary gland (gland in the mouth that makes saliva). Most salivary gland cancers occur in older people.

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

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.

Examination under a microscope of cells found in sputum (mucus and other matter brought up from the lungs by coughing). The test checks for abnormal cells, such as lung cancer cells.

Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.

Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.

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.