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.
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.
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.
- Streaks of blood in sputum (mucus coughed up from the lungs).
- 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.