Lung cancer is the leading cancer killer in both men and women. An estimated 173,700 new cases of lung cancer and an estimated 160,440 deaths from lung cancer will occur in the United States during 2004.
The rate of lung cancer cases appears to be dropping among white and African-American men in the United States, while it continues to rise among both white and African-American women.
There are two major types of lung cancer: non-small cell lung cancer and small cell lung cancer. Non-small cell lung cancer is much more common. It usually spreads to different parts of the body more slowly than small cell lung cancer. Squamous cell carcinoma, adenocarcinoma, and large cell carcinoma are three types of non-small cell lung cancer. Small cell lung cancer also called oat cell cancer, accounts for about 20% of all lung cancer.
WHAT CAUSES LUNG CANCER?
Smoking is the number one cause of lung cancer. Lung cancer may also be the most tragic cancer because in most cases, it might have been prevented—87% of lung cancer cases are caused by smoking. Cigarette smoke contains more than 4,000 different chemicals, many of which are proven cancer-causing substances, or carcinogens. Smoking cigars or pipes also increases the risk of lung cancer.
The more time and quantity you smoke, the greater your risk of lung cancer. But if you stop smoking, the risk of lung cancer decreases each year as normal cells replace abnormal cells. After ten years, the risk drops to a level that is one-third to one-half of the risk for people who continue to smoke. In addition, quitting smoking greatly reduces the risk of developing other smoking-related diseases, such as heart disease, stroke, emphysema and chronic bronchitis.
Many of the chemicals in tobacco smoke also affect the nonsmoker inhaling the smoke, making “secondhand smoking” another important cause of lung cancer. It is responsible for approximately 3,000 lung cancer deaths annually.
Radon is considered to be the second leading cause of lung cancer in the U.S. today. Radon gas can come up through the soil under a home or building and enter through gaps and cracks in the foundation or insulation, as well as through pipes, drains, walls or other openings. Radon causes between 15,000 and 22,000 lung cancer deaths each year in the United States—12 percent of all lung cancer deaths are linked to radon.
Radon problems have been found in every state. The EPA estimates that nearly 1 out of every 15 homes in the U.S. has indoor radon levels at or above the level at which homeowners should take action—4 picocuries per liter of air (pCi/L) on a yearly average. Radon can be a problem in schools and workplaces, too.
Because you cannot see or smell radon, the only way to tell if you are being exposed to the gas is by measuring radon levels. Exposure to radon in combination with cigarette smoking greatly increases the risk of lung cancer. That means for smokers, exposure to radon is an even greater health risk.
Another leading cause of lung cancer is on-the-job exposure to cancer-causing substances or carcinogens. Asbestos is a well-known, work-related substance that can cause lung cancer, but there are many others, including uranium, arsenic, and certain petroleum products.
There are many different jobs that may involve exposure. Some examples are working with certain types of insulation, working in coke ovens, and repairing brakes. When exposure to job-related carcinogens is combined with smoking, the risk of getting lung cancer is sharply increased.
A recent study published in the Journal of American Medical Association suggests that particulate matter pollution can cause lung cancer.
Lung cancer takes many years to develop. But changes in the lung can begin almost as soon as a person is exposed to cancer-causing substances. Soon after exposure begins, a few abnormal cells may appear in the lining of the bronchi (the main breathing tubes). If a person continues to be exposed to the cancer-causing substance, more abnormal cells will appear. These cells may be on their way to becoming cancerous and forming a tumor.
HOW IS LUNG CANCER DETECTED?
In its early stages, lung cancer usually does not cause symptoms. When symptoms occur, the cancer is often advanced. Symptoms of lung cancer include:
- Chronic cough
- Coughing up blood
- Weight loss & loss of appetite
- Shortness of breath
- Fever without a known reason
- Repeated bouts of bronchitis or pneumonia
- Chest pain
These conditions are also symptomatic of many other lung problems, so a person who has any of these symptoms should see a doctor to find out the cause. When a person goes for an exam, the doctor ask many questions about the person’s medical history, including questions about the patient’s exposure to hazardous substances. The doctor will also give the patient a physical exam. If the patient has a cough that produces a sputum (mucus), it may be examined for cancer cells. The doctor will order a chest X-ray or specialized X-ray such as the CT scan, which help to locate any abnormal spots in the lungs. The doctor may insert a small tube called a bronchoscope through the nose or mouth and down the throat, to look inside the airways and lungs and take a sample, or biopsy, of the tumor. This is just one of several ways in which a doctor may take a biopsy sample.
A growing number of doctors are using a form of CT scan in smokers to spot small lung cancers, which are more likely than large tumors to be cured. The technique, called helical low-dose CT scan, is much more sensitive than a regular X-ray and can detect tumors when they are small.
More studies on this type of screening will show whether routine screening of smokers and others at risk for lung cancer will save lives.
If you are diagnosed with cancer, the doctor will do testing to find out whether the cancer has spread, and, if so, to which parts of the body. This information will help the doctor plan the most effective treatment. Tests to find out whether the cancer has spread can include a CT scan, an MRI, or a bone scan.
HOW IS LUNG CANCER TREATED?
The doctor will decide which treatment you will receive based on factors such as the type of lung cancer, the size, location and extent of the tumor (whether or not it has spread), and your general health. There are many treatments, which may be used alone or in combination. These include:
SURGERY may cure lung cancer. It is used in limited stages of the disease. The type of surgery depends on where the tumor is located in the lung. Some tumors cannot be removed because of their size or location.
RADIATION THERAPY is a form of high energy X-ray that kills cancer cells. It is used:
- In combination with chemotherapy and sometimes with surgery.
- To offer relief from pain or blockage of the airways.
CHEMOTHERAPY is the use of drugs that are effective against cancer cells. Chemotherapy may be injected directly into a vein or given through a catheter, which is a thin tube that is placed into a large vein and kept there until it is no longer needed. Some chemotherapy drugs are taken by pill. Chemotherapy may be used:
- In conjunction with surgery.
- In more advanced stages of the disease to relieve symptoms.
- In all stages of small cell cancer.
Some patients may also be eligible to participate in clinical trials or research studies that look at new ways to treat lung cancer.
HOW CAN YOU PREVENT LUNG CANCER?
- If you are a smoker, stop smoking. Duh. The American Lung Association has books, videos, and group programs to help you quit for good.
- If you are a nonsmoker, know your rights to a smoke-free environment at work and in public places. Make your home smoke-free.
- Test your home for radon.
- If you are exposed to dusts and fumes at work, ask questions about how you are being protected. Don’t smoke—smoking increases your risk from many occupational exposures.