Lung cancers are generally divided into two types: small cell lung cancer and non-small cell lung cancer. The tumor cells of each type grow and spread differently, and they are treated differently. Small cell lung cancer is sometimes called oat cell cancer because the cancer cells looks like oats when they are viewed under a microscope. This type of lung cancer makes up about 20 to 25 percent of all cases. It is a rapidly growing cancer that spreads very early to other organs. It is generally found in people who are heavy smokers. There are three main kinds of non-small cell lung cancer, and they are named for the type of cells found in the cancer.
Lung cancer may cause a number of symptoms. A cough is one of the more common symptoms and is likely to occur when a tumor grows and blocks an air passage. Another symptom is chest pain, which feels like a constant ache that may or may not be related to coughing. Other symptoms may include shortness of breath, repeated pneumonia or bronchitis, coughing up blood, hoarseness, or swelling of the neck and face. In addition, there may be symptoms that do not seem to be at all related to the lungs.
These may be caused by the spread of lung cancer to other parts of the body. Depending on which organs are affected, symptoms can include headache, weakness, pain, bone fractures, bleeding, or blood clots. Hormones that are produced by lung cancer cells may cause some symptoms. For example, certain lung cancer cells produce a hormone that causes a sharp drop in the level of salt (sodium) in the body. A decrease in sodium level can produce many symptoms, including confusion and even coma. Like all cancers, lung cancer can also cause fatigue, loss of appetite, and loss of weight.
These symptoms may be caused by a number of problems. They are not a sure sign of cancer. However, it is important to see a doctor if any of these symptoms last as long as two weeks. Any illness should be diagnosed and treated as early as possible, and this is especially true of cancers. If lung cancer is suspected, a patient undergoes a series of tests to confirm whether cancer is present. Once cancer is diagnosed, doctors do more tests to learn if the disease has spread. This process is called staging.
When symptoms suggest that there might be cancer growing in the lungs, the first step for all patients is a complete physical examination. This includes telling about any health problems, work history, and anything else that might be important in learning the cause of the symptoms. The physical examination is usually followed by chest x-rays. Next, the doctor may want to collect cells from the lungs so that they can be examined under a microscope. This is important because it is the only sure way to know if cancer is present and, if it is, to identify the type of lung cancer. Doctors may collect cells by biopsy using a needle, surgery, or other methods.
In addition to chest x-rays, the patient may have other x-ray tests. For example, a lung tomogram is a series of x-rays of sections of the lung. A test called bronchoscopy permits the doctor to see the breathing passages through a thin, hollow, lighted tube. The tube is inserted through the patient’s nose or mouth into the lung. The doctor can collect cells from the bronchial walls or snip small pieces of tissue for study under the microscope. This test generally is done in hospitals. The patient, who is given a local anesthetic and is awake during the test, usually can go home a few hours later.
A new procedure used to collect cells that are hard to reach with the bronchoscope is called needle aspiration biopsy guided by fluoroscopy. Fluoroscopy is an x-ray test that uses a television screen so that internal organs, such as the heart can be viewed while they are in motion. Using the picture on the screen as a guide, the doctor inserts a needle into the tumor to withdraw cells for examination. Doctors also perform scans to locate lung cancer cells that may have spread to the brain, bone, or liver. In these tests, a substance that is mildly radioactive is injected into the blood, and a machine then scans the body to measure radiation and detect abnormal areas.
Treatment of lung cancer depends on the type of cells, the location of the tumor, and the stage of the cancer (whether it is just in the lungs or it has spread to other organs). After diagnosis and staging, the doctor develops a treatment plan to fit the type and location of the cancer as well as the patient’s medical history and general health.