Non-Small Cell Lung Cancer

General Information | Treatment Options | Prevention | Screening
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General Information
  • About
  • Risk Factors
  • Signs & Symptoms
  • Detection
  • Stages

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.

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 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.
  • 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.
  • 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.
  • 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.
  • 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.

After lung cancer has been diagnosed, tests are done to find out if cancer cells have spread within the lungs or to other parts of the body.

The process used to find out if cancer has spread within the lungs or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. Some of the tests used to diagnose non-small cell lung cancer are also used to stage the disease. (See the General Information section.) Other tests and procedures that may be used in the staging process include the following:

  • 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.
  • MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the brain. This procedure is also called nuclear magnetic resonance imaging (NMRI).
  • Radionuclide bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
  • Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography. EUS may be used to guide fine needle aspiration (FNA) biopsy of the lung, lymph nodes, or other areas.
  • Lymph node biopsy: The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells.
  • Mediastinoscopy: A surgical procedure to look at the organs, tissues, and lymph nodes between the lungs for abnormal areas. An incision (cut) is made at the top of the breastbone and a mediastinoscope is inserted into the chest. A mediastinoscope 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.
  • Anterior mediastinotomy: A surgical procedure to look at the organs and tissues between the lungs and between the breastbone and heart for abnormal areas. An incision (cut) is made next to the breastbone and a mediastinoscope is inserted into the chest. A mediastinoscope 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. This is also called the Chamberlain procedure.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for non-small cell lung cancer:

Occult (hidden) stage

In the occult (hidden) stage, cancer cells are found in sputum (mucus coughed up from the lungs), but no tumor can be found in the lung by imaging or bronchoscopy, or the primary tumor is too small to be checked.

Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the innermost lining of the lung. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed. Stage I is divided into stages IA and IB:

  • Stage IA: The tumor is in the lung only and is 3 centimeters or smaller.
  • Stage IB: One or more of the following is true:
    • The tumor is larger than 3 centimeters.
    • Cancer has spread to the main bronchus of the lung, and is at least 2 centimeters from the carina (where the trachea joins the bronchi).
    • Cancer has spread to the innermost layer of the membrane that covers the lungs.
    • The tumor partly blocks the bronchus or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).

Stage II

Stage II is divided into stages IIA and IIB:

  • Stage IIA: The tumor is 3 centimeters or smaller and cancer has spread to nearby lymph nodes on the same side of the chest as the tumor.
  • Stage IIB:
    • Cancer has spread to nearby lymph nodes on the same side of the chest as the tumor and one or more of the following is true:
      • The tumor is larger than 3 centimeters.
      • Cancer has spread to the main bronchus of the lung and is 2 centimeters or more from the carina (where the trachea joins the bronchi).
      • Cancer has spread to the innermost layer of the membrane that covers the lungs.
      • The tumor partly blocks the bronchus or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).
      or
    • Cancer has not spread to lymph nodes and one or more of the following is true:
      • The tumor may be any size and cancer has spread to the chest wall, or the diaphragm, or the pleura between the lungs, or membranes surrounding the heart.
      • Cancer has spread to the main bronchus of the lung and is no more than 2 centimeters from the carina (where the trachea meets the bronchi), but has not spread to the trachea.
      • Cancer blocks the bronchus or bronchioles and the whole lung has collapsed or developed pneumonitis (inflammation of the lung).

Stage IIIA

In stage IIIA, cancer has spread to lymph nodes on the same side of the chest as the tumor. Also:

  • The tumor may be any size.
  • Cancer may have spread to the main bronchus, the chest wall, the diaphragm, the pleura around the lungs, or the membrane around the heart, but has not spread to the trachea.
  • Part or all of the lung may have collapsed or developed pneumonitis (inflammation of the lung).

Stage IIIB

In stage IIIB, the tumor may be any size and has spread:

  • To lymph nodes above the collarbone or in the opposite side of the chest from the tumor; and/or
  • To any of the following:
    • Heart.
    • Major blood vessels that lead to or from the heart.
    • Chest wall.
    • Diaphragm.
    • Trachea.
    • Esophagus.
    • Sternum (chest bone) or backbone.
    • More than one place in the same lobe of the lung.
    • The fluid of the pleural cavity surrounding the lung.

Stage IV

In stage IV, cancer may have spread to lymph nodes and has spread to another lobe of the lungs or to other parts of the body, such as the brain, liver, adrenal glands, kidneys, or bone.

Recurrent Non-Small Cell Lung Cancer

Recurrent non-small cell lung cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the brain, lung, or other parts of the body.

Cancer information from the NCI PDQ service