Lung cancer is a disease which consists of uncontrolled cell growth in tissues of the lung. This growth may lead to metastasis, which is the invasion of adjacent tissue and infiltration beyond the lungs. The vast majority of primary lung cancers are carcinomas, derived from epithelial cells. Lung cancer, the most common cause of cancer-related death in men and women, is responsible for 1.3 million deaths worldwide annually, as of 2004. The most common symptoms are shortness of breath, coughing (including coughing up blood), and weight loss.
The main types of lung cancer are small-cell lung carcinoma and non-small-cell lung carcinoma. This distinction is important, because the treatment varies; non-small-cell lung carcinoma (NSCLC) is sometimes treated with surgery, while small-cell lung carcinoma (SCLC) usually responds better to chemotherapy and radiation. The most common cause of lung cancer is long-term exposure to tobacco smoke. The occurrence of lung cancer in nonsmokers, who account for as many as 15% of cases, is often attributed to a combination of genetic factors, radon gas, asbestos, and air pollution including secondhand smoke. Lung cancer may be seen on chest radiograph and computed tomography (CT scan). The diagnosis is confirmed with a biopsy. This is usually performed by bronchoscope or CT-guided biopsy. Treatment and prognosis depend upon the histological type of cancer, the stage (degree of spread), and the patient's performance status. Possible treatments include surgery, chemotherapy, and radiotherapy. Survival varies, depending on stage, overall health, and other factors, but the overall five-year survival rate for all persons diagnosed with lung cancer is 14%.
Unfortunately, the symptoms of lung cancer can take many years to develop which often leads to diagnosis at an advanced stage of this disease. Some of the symptoms that may occur include:
- Smoker's cough that persists or becomes intense.
- Persistent chest, shoulder, or back pain unrelated to pain from coughing.
- Increase in volume of sputum.
- Wheezing.
- Nonsmoker's cough that persists for more than 2 weeks.
- Change in color of sputum.
- Blood in sputum.
- Repeated episodes of pneumonia or bronchitis.
Other symptoms that can be related to late-stage lung cancer can include:
- Fatigue.
- Loss of appetite.
- Headache, bone pain, aching joints.
- Bone fractures not related to accidental injury.
- Neurologic symptoms, such as unsteady gait and/or episodic memory loss.
- Neck and facial swelling.
- Unexplained weight loss.
Other signs and symptoms may be caused by the spread of lung cancer to other parts of the body, including headaches, weakness, pain, bone fractures, bleeding, or blood clots.
If you or someone you know experiences any of these signs or symptoms consult a physician immediately. Early detection can mean the difference between life and death for lung cancer patients--the 5-year survival rate for patients whose cancer is found while it is still localized (affecting only the lungs) is almost fifty percent.
If your physician is suspicious of your symptoms he can order screening tools such as CT scans and PET scans which can detect lung cancer earlier than conventional X-rays and increase your chance of survival. Source
The most common cause of lung cancer is smoking.
Smoking causes lung cancer because there are substances within tobacco that are known to cause cancer. These substances are known as carcinogens (which means "cancer-causing agents"), and it is these carcinogens that cause the actual damage to the cells in the lungs. A cell that is damaged may become cancerous over a period of time.
One cannot predict which smoker is at greater risk of developing lung cancer. In general, though, a smoker's chances of developing cancer depends on:
- The age that the person began smoking
- How long the person has smoked
- How many cigarettes per day the person smokes
Passive smoking - breathing in someone else's smoke - may also increase the risk for developing lung cancer.
There are other causes of lung cancer not related to smoking. People who smoke and who also are exposed to these other causes have an even higher risk for lung cancer.
These other causes include:
- Exposure to cancer-causing agents through a person's job. This includes exposure to asbestos, either in the mining or construction industries. Inhaled asbestos particles may remain in the lungs, damaging lung cells. It also includes exposure to certain industrial substances like coal products, vinyl chloride, nickel chromate, arsenic, and exposure to some organic chemicals like chloromethyl ethers.
- Exposure to radiation, either through one's occupation or for medical reasons, such as repeated x-rays, though this is quite uncommon.
- Radon gas, which occurs naturally in rocks and soil in certain areas, may cause lung damage and may eventually result in lung cancer if it seeps into your home. The presence of radon in the home can be measured using an inexpensive kit that can be purchased at department or hardware stores.
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