About Lung Cancer

• Types of Lung Cancer
• Risk Factors
• Symptoms
• Diagnosis

What is Lung Cancer?

The lungs are a pair of sponge-like organs that work with the ribs and chest muscles to move air in and out of the body, bringing in oxygen (energy) and getting rid of carbon dioxide (waste). Lung cancer results from the uncontrolled growth of abnormal cells in one or both lungs. These cancer cells form lumps and disrupt the lung and/or the breathing tubes (bronchus), at times interfering with their normal function.

Lung cancer takes years to develop. Unfortunately, it is most often discovered after it has spread or metastasized throughout the body. Sometimes, however, lung cancer is detected earlier through a chest X-ray or other exam that has been conducted for an unrelated reason.

Lung cancer is a leading cause of cancer death for both men and women. It accounts for a third of all cancer deaths in our country. Each year, more Americans die of lung cancer than of colon, breast, and prostate cancers combined. Since the year 1984, lung cancer has killed more American women yearly than breast cancer. Close to 90 percent of lung cancers are smoking related.

In 2004, an estimated 173,770 new cases of lung cancer were diagnosed. In 2007, the estimate is 213,380 new cases in the United States will be diagnosed, resulting in an estimated 160,390 deaths from the disease, according to the American Lung Association. African American women have the highest incidence rates of lung cancer followed by Caucasians, Asian Pacific Islanders, Hispanics, and Native Americans.

 

Types of Lung Cancer
There are two main types of lung cancer: non-small cell (accounting for 80 percent of all lung cancers) and small cell (accounting for the remaining 20 percent).

Non-small cell lung cancer is classified into three main categories:

• Adenocarcinomas, which arise from the mucus glands;
• Squamous cell, or epidermoid carcinomas, which are usually located in the bronchial tubes; 
• Large cell carcinomas, which are more commonly found near the lung surface.

Small cell lung cancer, for the most part, grows and spreads quickly. There are two stages of the disease: limited and extensive.

Another less common type of chest cancer is called mesothelioma. This cancer lines the lungs, known as the pleura, and is often linked to exposure to asbestos.

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Risk Factors
Nearly 90 percent of all lung cancer cases are related to tobacco use, and approximately half of all continuing smokers will die from a disease caused by smoking. Cigarette smoke contains more than 4,000 chemicals, many of them cancer-causing substances (carcinogens) that damage the cells in the lungs. Over time the damaged cells become cancerous. Lung cancer occurs most frequently among people over 50 who have smoked for many years. Former tobacco users who stop smoking lessen their risk of developing a lung cancer over time. Too often, however, cancer will still develop in former smokers, years after they have kicked the habit.

Other risk factors include: exposure to radon, asbestos, and some organic chemicals; radiation exposure from occupational, medical or environmental sources; air pollution; tuberculosis; and exposure to certain industrial substances, such as arsenic. Tobacco use combined with one of these other risk factors can increase the risk of developing lung cancer in an exponential manner. Back to Top

 

Symptoms
The signs and symptoms of lung cancer can take years to develop and are often confused with less serious symptoms that are often thought to be related to tobacco usage alone. These symptoms may include any of the following: a persistent cough that lasts for more than two weeks; a chest infection that doesn't get better; recurrent pneumonia or bronchitis; shortness of breath; coughing up of blood; chest discomfort; loss of appetite; loss of weight; neck and facial swelling; and/or aching joints. Back to Top

 

Diagnosis
There are several tools used to diagnose lung cancer. A doctor may order a chest X-ray, as well as a sputum cytology (a microscopic examination of the mucus in the lungs).

A biopsy must be performed in order to confirm the presence of lung cancer. A number of methods can be used. In a bronchoscopy, a thin, lighted tube is inserted in the mouth or nose and down the windpipe into breathing passages. In a needle aspiration, a needle is inserted through the chest wall into the tumor, usually under the guidance of X-ray imaging. In a thoracentesis, a needle is used to remove fluid surrounding the lungs. In a thoracotomy, the chest is surgically opened. In a bone marrow biopsy, a needle is used to remove a small piece of bone, usually from the back of the hip bone.

If the biopsy confirms that cancer is present, your doctor will need to determine whether the disease has spread. Several methods are used to determine the stage of the disease, including: a computed tomography (CT) scan (an X-ray machine linked to a computer which creates a series of detailed pictures of areas inside the body); a magnetic resonance imaging (MRI) scan (a magnet connected to a computer which uses radio frequency waves to make detailed pictures of areas inside the body); a positron emission tomography (PET) scan (a method of imaging the body's physiologic functions by scanning for a radioactive substance that may collect in cancer cells); and a mediastinoscopy (a lighted scope inserted through an incision in the neck to access chest lymph nodes that may contain cancer). Back to Top 

 

February 2007