Lung cancer 101: Learning the facts
Posted: Wednesday, November 30, 2011 8:02 pm
Lung cancer is the uncontrolled growth of abnormal cells in one or both lungs. These abnormal cells do not carry out the functions of normal cells and do not develop into healthy lung tissue. As they grow, the abnormal cells can form tumors and impede the function of the lung, which is to provide oxygen to the body via the blood.All cells in the body contain the genetic material called deoxyribonucleic acid (DNA). Every time a mature cell divides into two daughter cells, it replicates its DNA exactly. The daughter cells are clones of the original cell, identical in every way. It is in this way that our bodies continually replenish themselves. Old cells die off and the next generation takes their place.
A cancer begins with an error, or mutation, in a cell’s DNA. DNA mutations can be caused by the normal aging process or through environmental factors, such as cigarette smoke or breathing in asbestos.
Researchers have found that it takes a series of genetic changes to create a lung cancer cell. Before becoming fully cancerous, cells can be precancerous, which means they have some irregularities (mutations) but still function as lung cells. However, precancerous changes may signify progression toward cancer. When a cell with a genetic mutation divides, it passes along its abnormal genes to the two daughter cells, which then divide into four cells with errors in their DNA and so on. Once a cell has a genetic mutation, it may develop more. With each new mutation, the cell becomes more irregular and may not be as effective in carrying out their function in lung tissue. At a later stage of disease, some cells can migrate away from the main tumor and start growing in other parts of the body. These sites are called metastases.
Lung cancer is one of the most common cancers. In 2007, lung cancer will account for approximately 15 percent of all cancer diagnoses and 28 percent of all cancer deaths. It is the second most diagnosed cancer in men and women (after prostate and breast, respectively), but it is the number one cause of death from cancer each year in both men and women. Because lung cancer can take years to develop, it is mostly found in older people. The average age of a person receiving a lung cancer diagnosis is 71 years.
Overall, lung cancer affects men more than women, but that gap is closing. The American Cancer Society’s most recent lung cancer statistics in the United States for 2009 include an estimated 116,900 men and 103,350 women will be diagnosed with lung cancer and an estimated 88,900 men and 70,490 women will die from lung cancer.
Cigarette smoking is the cause of most lung cancers, but there are other factors, too. Exposure to asbestos, radon, environmental factors, or secondhand smoke can cause lung cancer. Sometimes, a person develops lung cancer and doctors do not know why.
There are often internal factors (inherited or from our genes) as well as external or environmental factors (from outside of our bodies) involved in the development of any type of cancer.
Lung cancer is the subject of a great amount of research. Promising areas of research include the study of chemopreventive agents and research into targeted therapies, both of which show potential to halt the progression of the development of a cancer cell. However, lung cancer does not receive as much attention, both in funding and in public awareness, compared to other types of cancers that are not as common.
Advocates for lung cancer research are working hard to raise awareness of this imbalance.