Symptoms & Diagnosis Of Lung Cancer

Lung cancer usually does not cause symptoms when it first develops. Doctors sometimes discover lung cancer in a person with no symptoms after the individual has a chest x-ray for another medical reason. Usually, however, lung cancer is found after the growing tumor causes symptoms to appear.

A cough is the most common symptom of lung cancer. It is likely to occur when a tumor irritates the lining of the airways or blocks the passage of air. The person may have a “smoker's cough” that becomes worse. Another symptom is constant chest pain. Other symptoms may include shortness of breath, wheezing, repeated bouts of pneumonia or bronchitis, coughing up blood, or hoarseness. A tumor that presses on large blood vessels near the lung can cause swelling of the neck and face. If the tumor presses on certain nerves near the lung, it can cause pain and weakness in the shoulder, arm, or hand.

In addition, there may be symptoms that do not seem to be at all related to the lungs. Like all cancers, lung cancer can cause fatigue, loss of appetite, and loss of weight. If the cancer spreads to other parts of the body, it may cause headache, pain, or bone fractures.

Other symptoms can be caused by substances made by lung cancer cells. Doctors often refer to these symptoms as a paraneoplastic syndrome. For example, certain lung cancer cells produce a substance that causes a sharp drop in the level of salt (sodium) in the blood. A decrease in the sodium level can cause many symptoms, including confusion and sometimes even coma.

None of these symptoms is a sure sign of lung cancer. Only a doctor can tell whether a patient's symptoms are caused by cancer or by another problem.

Diagnosis

To find the cause of any of these symptoms, the doctor asks about the patient's personal and family medical background as well as smoking and work history. The doctor also does a physical exam and usually orders x-rays and other tests.

In addition to chest x-rays, the doctor may order other pictures of areas inside the body. For example, a CT scan (also called a CAT scan) is a series of x-ray images put together by a computer. These detailed pictures can reveal that a tumor is in the lung, but they cannot show whether the tumor is benign or malignant.

The only sure way to know whether cancer is present is to obtain cells from the lungs so that a pathologist can examine them under a microscope. Sometimes, cancer cells can be found in the sputum, a thick fluid that the patient coughs up from deep in the airways. Also, the doctor usually does a biopsy to remove a sample of cells from the lung. To do a biopsy, the doctor uses one of the procedures described below:

• An exam called bronchoscopy permits the doctor to look into the breathing passages through a bronchoscope (a thin, lighted tube). A local anesthetic reduces discomfort and gagging, and medicine helps the patient relax as the doctor inserts the tube through the nose or mouth. (A general anesthetic may be used instead to put the patient to sleep.) The doctor can brush or wash cells from the walls of bronchi or snip off small pieces of tissue for study under a microscope.
  
• Needle aspiration is a procedure to remove cells that are hard to reach with the bronchoscope. After the patient is given a local anesthetic, the doctor inserts a needle through the chest into the tumor to withdraw a small sample of tissue. Most often, the doctor uses fluoroscopy or CT scans to locate the tumor.
  
• Sometimes, examination of fluid from the pleura (the fluid-filled sac that surrounds the lungs) can reveal lung cancer. Using a needle, the doctor removes a sample of the fluid in the pleura and checks it for cancer cells. For this procedure, called thoracentesis, the patient receives a local anesthetic.
  
• For some patients, surgery is needed to diagnose lung cancer. Surgery to open the chest (for diagnosis or treatment) is called thoracotomy. This is major surgery and is done under a general anesthetic.

If the doctor can feel swollen lymph nodes or an enlarged liver, these areas may be biopsied to help with the diagnosis. The doctor also may biopsy other sites of the body where cancer is suspected.

A patient who needs a biopsy may want to ask the doctor these questions:

• What type of biopsy will I have? Why?
• How long will it take? Will I be awake? Will it hurt?
• How soon will I know the results?
• If I do have cancer, who will talk with me about treatment? When?

Staging

If lung cancer is diagnosed, the patient's doctor needs to learn the stage, or extent, of the disease so that proper treatment can be given. Staging is a careful attempt to find out whether the cancer has spread and, if so, what parts of the body are affected.

To find out whether a patient's lung cancer has spread to the lymph nodes in the chest, the doctor removes a sample of the tissue. In some patients, this can be done with a needle; in others, the doctor will need to perform surgery. Surgery to biopsy lymph nodes in the chest can often be done through a small incision near the breastbone. This procedure is called mediastinoscopy when the incision is above the breastbone and mediastinotomy when the incision is on one side of the breastbone. If a thoracotomy is planned, the doctor removes lymph nodes during the operation. Patients receive a general anesthetic for any of these operations.

Doctors may order CT scans to detect the spread of lung cancer to the lymph nodes and other parts of the body. Radionuclide scans of the bones, brain, or liver also may help doctors find out whether the cancer has spread. In these tests, a small amount of radioactive material is injected into a vein. A machine then scans the body to measure the radiation and reveal abnormal areas.

In another technique, called MRI (for magnetic resonance imaging), a strong magnet linked to a computer is used to produce images. Doctors may order MRI to see whether lung cancer has spread to the brain or spinal cord.

Source: “What You Need To Know About Lung Cancer,” Brochure, NIH Publication Number 93-1553, National Cancer Institute, June 1993.

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