Lung cancer - II - Causes

Smoking

Incidence of lung cancer is correlated with smoking, about 90% of cases with smoking as the main cause. The risk increases with increasing the number of cigarettes smoked (doctors talk about this risk in terms of packs of cigarettes smoked per year, for example a person who smokes 1 pack per day for 10 years is known to have a history of 10 packs - years of smoking).



Pipe or cigar smoking is not healthy but have a slightly lower risk.
Cigarette smoke contains over 4,000 chemicals, many of which are certainly, scientific proved carcinogens. The risk of lung cancer decreases each year elapsed since quitting smoking. The risk comes close to the people who do not smoke at about 15 years of quitting smoking. This period is necessary for the body to replace damaged cells with healthy others. Are you a smoker? Quit today!

Passive smoking

Passive smoking is the inhalation of cigarette smoke by people who, although not smoke, live or work with people who smoke. The risk of these personae of the disease is 24% higher risk than those who do not smoke.

Asbestos fibers

Asbestos fibers are silicate fibers that were used in the past to insulate and protect the premises or to cover the various buildings. Presently the use of these fibers is prohibited or permitted only under special conditions. Asbestos fibers penetrated into the lungs may persist there for years, eventually generating disease. Cancer risk increases pulmonary extreme than if smokers working in environments contaminated by asbestos fibers.

Radon

Radon is an inert gas that occurs as a secondary product in the reaction of obtaining uranium. About 12% of lung cancer cases are due to radon. Although it is a colorless gas and have no smell there is technology for detection and annihilation of radon.

Genetics

Although most cases of lung cancer are directly related to smoking, there are cases of nonsmokers who develop the disease; this seems to suggest that the disease may be triggered genetically. Recent research seems to indicate that the gene responsible for lung cancer in nonsmokers is located on human chromosome no. 6.

Pollution

Pollution generated by cars, factories, chemical plants increases the risk of lung cancer among those exposed. About 1% of deaths are due to pollution. Experts believe that breathing polluted air present the same risk of passive smoking.


To be continued

Lung cancer - I - Intro

Lung cancer is a serious, high risk disease. There are many important things to be said about this disease, so we will structure this article into more chapters. This one is the first one.

Lung cancer, like all cancers, result from an anomaly in the fundamental unit of life cell. Normally the body maintains a system of checks and balances on economic growth in cells such as cells divide to produce new cells only when necessary. Disorders of this system of checks and balances result in an increase in cell division and uncontrolled proliferation of cells that eventually forms a mass known as tumor.

Benign tumors can usually be removed and not spread to other parts of the body. Malignant tumors, on the other hand, grow aggressively and invade other tissues of the body, which allows entry of tumor cells in the blood or lymphatic system and then to other organs. This spread is called metastasis; tumor growth areas in these organs are called metastases. Since lung cancer tends to spread or develop metastases very early, we can say that is a serious form of cancer, high risk and it is also difficult to treat.

While lung cancer can spread to any organ in the body, certain organs - particularly the adrenal glands, liver, brain, bones are the organs most commonly affected, with a high risk of developing metastases. Metastasis tumor is composed of the same type of cells as the original tumor. For example, prostate cancer, if it spreads through the blood to the lungs, talk about prostate cancer in lung cancer, not lung cancer.

The main function of the lungs is gas exchange between blood and the air we breathe. The work of the lungs, carbon dioxide is removed from the blood and the inspired oxygen enters the bloodstream. Right lung has three lobes, whereas left lung is divided into two lobes and a smaller structure called the lingula which is equivalent to the middle lobe. Major airways into the lungs are the bronchi, resulting in the trachea. Bronchi branch into progressively smaller airways called bronchiole. They end in small bags known as pulmonary alveoli. The wafers are exchanged gas itself. Lungs and chest wall are covered with a thin layer of tissue called pleura.

Various types of lung cancer can occur in any part of the lung, but 90% -95% of lung cancer cases are believed to originate from epithelial tissues, or cells lining the respiratory tract and older children (bronchi and bronhiolele), for this reason, forms of cancer are bronhogenics sometimes called carcinoma or bronchogenic cancers. Cancers can arise also from the pleura (thin layers of tissue surrounding the lungs) or, rarely, from blood vessels.

Lung cancer is the most common cause of death among people with cancer. According to the U.S. National Cancer Institute, about 1 in 14 people in USA will contact disease during their life.
Lung cancer generally occurs in older age, 70% of those affected with over 65 years, only 3% of cases occur in people under 45 years.
Pulmonary cancer was a relatively rare disease before 1930, but the number of cases increased rapidly with the increasing number of smokers, and developing industrialization.
Lately however is noted a slight decrease in the number of cases due to awareness of the negative role of smoking and quitting the habit and also because anti-tobacco campaigns.
However, lung cancer remains the leading cause of death among females; the number of deaths exceeded the number of deaths due to breast cancer.

(To be continued)