Most lung cancer is caused by tobacco use. Lung cancer accounts for the most cancer-related deaths in both men and women. An estimated 231,380 new cases are expected in 2007.
Lung cancer often takes many years to develop. First, there may be areas of pre-cancerous changes in the lung. These changes are not masses or tumors. They can't be seen on an X-ray and they don't cause symptoms. As these pre-cancerous areas change and mutate to become cancer, they create chemicals that cause new blood vessels to form nearby. These new blood vessels nourish the cancer cells and allow a tumor to form. Finally, the tumor becomes large enough to be seen on an X-ray.
Once lung cancer occurs, cancer cells can break away and spread to other parts of the body in a process called metastasis. Lung cancer is a life-threatening disease because it often spreads in this way before it is found.
There are different types of lung cancers that are characterized by the cells that make up the tumors. One quarter of all lung cancers are called small-cell lung cancers. This type of lung cancer grows the fastest and quickly spreads to other organs.
Non-small-cell lung cancer (NSCLC) is the most common type of lung cancer. There are three kinds of NSCLC:
Squamous cell carcinoma is the most common type of lung cancer in men. It spreads at a slower rate than other lung cancers, and often begins in the bronchial tubes.
Adenocarcinoma is the most common type of lung cancer in women and in people who have never smoked. It usually begins along the outer edges of the lungs, under the lining of the bronchi.
Large cell carcinomas are a group of cancer with large abnormal looking cells. These tumors usually begin along the outer edges of the lung.
About 213,380 Americans are estimated to be diagnosed with lung cancer in 2007.
Lung cancer is the number-one cancer-killer in the
Lung cancer will account for 29 percent of all cancer deaths.
Often slow to develop, its symptoms can go undetected for as long as 10 to 20 years.
Although lung cancer death rates are declining significantly for men, they are on the rise for women.
Tobacco use is related to one-third of all cancer and 80 percent of all lung cancer. The best way to prevent lung cancer is not to smoke. If you already smoke, you should try to quit.
The longer you use tobacco, the greater your risk becomes. Research shows that the chances of developing lung cancer decrease once you quit and continue to abstain from tobacco for a long period of time.
You should also avoid breathing in other people's smoke. Nonsmokers exposed to secondhand smoke are at an increased risk for developing lung cancer. A nonsmoker living with a smoker has a 25 percent increased risk for lung cancer.
Never expose children to secondhand smoke. Prolonged exposure can interfere with normal lung development and increase their risk of developing respiratory illnesses such as asthma.
In the workplace, follow work and safety guidelines to reduce your exposure to hazardous chemicals and second-hand smoke.
A good diet with lots of fruits and vegetables may also help prevent lung cancer.
Cigarette smoking is by far the the leading risk factor in the development of lung cancer. Over 80 percent of lung cancers are caused by smoking. If a person quits smoking before lung cancer develops, the lung tissue slowly returns to normal. Quitting smoking at any age lowers the risk of lung cancer. Smoking low tar cigarettes does not reduce the risk of lung cancer.
- Prolonged exposure to second-hand smoke
- Occupations with exposure to hazardous agent such as arsenic, radon, gasoline, diesel exhaust, chloride, uranium, vinyl and asbestos
- Exposure to chemical products
- Radiation exposure
- Exposure to air pollution
- Tuberculosis
- Personal and family history: If you have had lung cancer, you have a higher risk of getting another lung cancer. Brothers, sisters, and children of people who have had lung cancer may have a slightly higher risk themselves.
A person is usually diagnosed with lung cancer after the growing tumor causes symptoms to appear. At this stage, the cancer cannot be treated as easily, showing why practicing prevention through a healthy lifestyle is so important.
- A persistent cough (the most common symptom)
- Constant chest pain
- Shortness of breath
- Wheezing
- Hoarseness
- Recurring pneumonia or bronchitis
- Coughing up blood
- Unusual or unexplained fatigue
- Swelling and redness of the neck or face
- Loss of appetite and loss of weight
- When lung cancer spreads to distant organs, it may cause:
- Bone pain
- Weakness or numbness of the arms or legs
- Dizziness or seizure
- Yellow coloring of the skin and eyes (jaundice)
- Masses near the surface of the body, caused by cancer spreading to the skin or to lymph nodes in the neck or above the collarbone
Regardless of your age, if any of these symptoms lasts longer than two weeks, immediately schedule an appointment with your health care provider.
Lung cancer is difficult to detect at an early stage, because symptoms do not appear until the disease has advanced. That is why prevention – particularly not smoking – is so important.
Chest x-rays are typically performed in addition to a physical exam to diagnose lung cancer. Analysis of sputum cells (spit) that is coughed up from the lungs and checked for cancer cells or a fiber optic examination of bronchial passages may also be done to assist in a diagnosis.
A spiral CT scan (spiral computerized tomography (CT) scan) is a painless procedure that produces three-dimensional, cross-sectional images of the lung. It is being investigated as a lung cancer early detection tool. Unlike conventional chest x-ray – used to diagnose lung cancer today, the CT scan can visualize much smaller growths (nodules) that may be an early tumor, as well as show changes in lung tissue that may lead to cancer.
As the result of recent research, the spiral CT is now recommended as a screening tool for smokers and former smokers. Continued research now underway is helping to clarify whether spiral CT scan can help increase survival for these high risk patients.
Other new tests for molecular markers (genetic changes that may occur before cancer develops or when it is in its early stages) in sputum may detect lung cancer earlier than traditional tests. Researchers are currently evaluating the effectiveness of these tests for screening people without symptoms of lung cancer.
Once lung cancer is diagnosed, more tests will determine the type and stage of the cancer – whether it is confined to the lungs or if it has spread to other parts of the body. Non small cell lung cancer is staged from Stage 0 (carcinoma in situ) through Stage IV (cancer has spread to other parts of the body or to another lobe of the lung). Small cell lung cancer is classified as limited stage or extensive stage small cell lung cancer.
Surgery is most often performed for non-small cell lung cancer. Surgery will remove the tumor and some of the lung around the tumor. When part of the lobe of a lung is removed the procedure is called a wedge resection. A lobectomy removes the whole lobe and a pneumonectomy removes the entire lung. If the cancer has spread to nearby tissue or lymph nodes surgery may be followed by radiation therapy alone or in combination with chemotherapy. Sometimes radiation therapy is given alone. When non-small cell lung cancer has spread to other parts of the body or the other lobe of the lung, radiation may be used to shrink the tumor and relieve symptoms. Then chemotherapy is given to some patients. Chemotherapy is the administration of anti-cancer drugs through the mouth, by needle in a muscle or by placing the placing the drug directly into an organ — this is called regional chemotherapy and may be used in some patients.
Sometimes radiation therapy uses external beams of x-rays to kill cancer cells. In other instances, internal radiation is used in which radioactive material is inserted into or near the cancer through needles or wires. Some patients may receive laser therapy in which a laser beam of intense light is used to kill cancer cells. Surgery, radiation, chemotherapy and laser therapy may be used in various combinations.
Small cell lung cancer is treated by surgical removal of the lung where the cancer is found and the nearby lymph nodes. If cancer is found in both lungs, surgery is not often used. Laser therapy may be used to kill cancer cells as well. Chemotherapy is given in combination with radiation therapy to the organ affected such as the brain, spine or bone. A combination of drugs may also be given along with radiation.
New treatments for non-small cell lung cancer are being studied and include phytodynamic therapy that uses light to activate certain drugs and biologic therapy that boosts patients own immune systems.
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