Non-small cell lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung.

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.

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. 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 radionuclide 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 biopsy of the lung: The removal of part of a lump, suspicious tissue, or fluid from the lung, using a thin needle. This procedure is also called needle biopsy. Ultrasound or another 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.
  
• Bronchoscopy: A procedure to look inside the trachea and large airways in the lung for abnormal areas. A bronchoscope (a thin, lighted tube) is inserted through the nose or mouth into the trachea and lungs. Tissue samples may be taken for biopsy.
  
• 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 (a thin, lighted tube) is inserted into the chest. Tissue samples and lymph nodes may be removed for biopsy. This procedure may be used to remove parts 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.

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.
  
• 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.
  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).
  
• Endoscopic ultrasound (EUS): A procedure in which an endoscope (a thin, lighted tube) is inserted into the body. 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 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 an endoscope (a thin, lighted tube) is inserted into the chest. Tissue and lymph node samples may be taken for biopsy.
  
• Anterior mediastinotomy: A surgical procedure to look at the organs and tissues between the lungs and between the breastbone and spine for abnormal areas. An incision (cut) is made next to the breastbone and an endoscope (a thin, lighted tube) is inserted into the chest. Tissue and lymph node samples may be taken for biopsy. This is also called the Chamberlain procedure.
  
• 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.

There are different types of treatment for patients with non-small cell lung cancer.

Different types of treatments are available for patients with non-small cell lung cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. Before starting treatment, patients may want to think about taking part in a clinical trial. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment.

Clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site. Choosing the most appropriate cancer treatment is a decision that ideally involves the patient, family, and health care team.

Six types of standard treatment are used:

Surgery

Four types of surgery are used:

• Wedge resection: Surgery to remove a triangle-shaped slice of tissue. Wedge resection is used to remove a tumor and a small amount of normal tissue around it. When a slightly larger amount of tissue is taken, it is called a segmental resection.
  
• Lobectomy: Surgery to remove a whole lobe (section) of the lung.
  
• Pneumonectomy: Surgery to remove one whole lung.
  
• Sleeve resection: Surgery to remove part of the bronchus.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.

Radiosurgery is a method of delivering radiation directly to the tumor with little damage to healthy tissue. It does not involve surgery and may be used to treat certain tumors in patients who cannot have surgery.

The way the radiation therapy is given depends on the type and stage of the cancer being treated.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Laser therapy

Laser therapy is a cancer treatment that uses a laser beam (a narrow beam of intense light) to kill cancer cells.

Photodynamic therapy (PDT)

Photodynamic therapy (PDT) is a cancer treatment that uses a drug and a certain type of laser light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein. The drug collects more in cancer cells than in normal cells. Fiberoptic tubes are then used to deliver the laser light to the cancer cells, where the drug becomes active and kills the cells. Photodynamic therapy causes little damage to healthy tissue. It is used mainly to treat tumors on or just under the skin or in the lining of internal organs.

Watchful waiting

Watchful waiting is closely monitoring a patient’s condition without giving any treatment until symptoms appear or change. This may be done in certain rare cases of non-small cell lung cancer.

New types of treatment and prevention are being tested in clinical trials. These include the following:

Chemoprevention

Chemoprevention is the use of drugs, vitamins, or other substances to reduce the risk of developing cancer or to reduce the risk cancer will recur (come back).

Biologic therapy

Biologic therapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This type of cancer treatment is also called biotherapy or immunotherapy.

New combinations

New combinations of treatments are being studied in clinical trials.