Lung cancer,
like all cancers, result from an abnormality in the body's basic unit of life
ie cells. Normally, the body maintains a system of inspections (checks) and
balances on the growth of cells so that cells divide to produce new cells only
when needed. Interruption or disruption of this system of checks and balances
on cell growth results in a division and proliferation of cells that are not
controlled, which in turn form a mass known as a tumor.
Tumors
can be benign or malignant; when we speak of "cancer", we refer to these tumors are considered malignant.
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, allowing the entry of tumor cells into the bloodstream or
lymphatic system tumors that spread to other places in the body. This
deployment process termed metastasis; the areas of tumor growth in places far
away called metastases. Since lung
cancer tends to spread, or metastasize, very early in its course, he is a
very life-threatening cancer and one of the cancers most difficult to treat.
Because lung cancer can spread to any organ in the body, certain organs -
particularly the adrenal glands, liver, brain, and bones - are places where the
most common for lung cancer spread.
The
lungs also is a place that most common cancers to spread
from other parts of the body. Areas of spread of tumors formed from the type of
cells the same as primary tumor. For example, if prostate cancer spreads
through the bloodstream to the lungs, it is prostate cancer that spread into
the lungs instead of lung cancer.
The main function of the lungs is the exchange of gases between the air we breathe and the blood. Through the lungs, carbon dioxide removed from the body and oxygen from the air entering the bloodstream. The right lung has three lobes, where the left lung is divided into two and a tiny structures called Lingula which is the same as the middle lobe. The streets of major air to enter the lungs are the bronchi, which branch from the trachea. Bronchi progressively branch off into the streets of smaller air called bronchioles which end in tiny sacs known as alveoli, where gas exchange occurs. Lung and chest wall is covered by a thin layer of tissue called the pleura.
Lung cancer
can occur anywhere section of the lung, and 90% -95% of lung cancers are
thought to arise from epithelial lung, or the cells lining the streets of
larger air and smaller (bronchi and bronchioles); for this reason, cancer, lung
cancer is sometimes called bronchogenic carcinomas or bronchogenic cancers. Cancers can also arise from the pleura
(the thin tissue layer that surrounds the lungs), called mesotheliomas, or
rarely from supporting tissues in the lungs, for example, the blood vessels.
How Common Lung Cancer?
Lung cancer
is responsible for most deaths caused by cancer in men and women around the
world. The American Cancer Society estimated that 213.380 new cases of lung
cancer in the United States will be diagnosed and 160.390 deaths due to lung
cancer will occur in 2007. Lung cancer is largely a disease of the elderly;
almost 70% of people who are diagnosed with this condition are over age 65
years, which is less than 3% of cases occur in people under the age of 45
years.
Lung cancer
is uncommon before the 1930s but increased dramatically over the next decades
when smoking increased. In many countries that are developing, the incidence of
lung cancer is beginning to decline following the public education about the
dangers of smoking and smoking cessation programs are effective. Nevertheless,
lung cancer remains among different types of the most common cancer in both men
and women around the world.
Lung
cancer has also been passed in the breast cancer cause the most deaths related
to cancer in women in America.