Lung cancer is the leading cause of cancer death in both men and women in the United States and Great Britain. It surpassed breast cancer as the leading cause of cancer death in women and in 2007, 160,390 people were projected to succumb to lung cancer. This number is greater than the number of deaths from colorectal, breast and prostate cancer combined.
Like any other cancer, lung cancer happens when normal cells transform and grow without normal controls. These cells form a mass or tumor that is different from the surrounding tissue and is dangerous because it takes oxygen, nutrients and space from a healthy cells. Most lung tumors are malignant, which means they invade and destroy the healthy tissue around them and can then spread through the body.
There are specific populations of people who are at higher risk of developing lung cancer than the general population. The biggest risk factor for developing lung cancer today is cigarette smoking. As far back as the 1950s research clearly establish the relationship between tobacco smoke and lung cancer.
Cigarettes contain more than 4000 chemicals, many of which are carcinogenic. This means that many of the chemicals in the cigarettes causes cancer. Added to the cigarettes is nicotine which is the drug that is addictive in nature. So while smoking one or two cigarettes a day will not cause lung cancer within a year, the nicotine in the cigarettes ensures that no one will ever smoke just one.
A person who smokes more than one pack a day increases their risk of developing lung cancer by 25 times greater than someone who has never smoked. However once a person quits smoking the risk for lung cancer will gradually decrease over time. This is because of the self-healing process which happens in the body as the lungs are gradually cleared of the build up of chemicals and carcinogenic factors.
Approximately 15 years after quitting, the risk for lung cancer will decrease to the level of someone who has never smoked. And while tobacco is the primary cause of lung cancer, cigar and pipe smoking increases the risk of lung cancer but not as much as cigarettes.
Researchers estimate that approximately 90% of people who develop lung cancer have used tobacco. This risk factor will also depends upon the number of cigarettes smoked, the age at which a person starts smoking and how long a person has smoked.
There are other causes or risk factors for lung cancer which can expose a person to developing this condition even though they never smoked. Some of those factors include exposure to cancer causing agents through a person’s work. This means that an individual may have been exposed to asbestos in the air environment which remains in the lungs and damages the cells. Other industrial substances such as coal products, vinyl chloride, nickel chromate, arsenic and exposure to some organic chemicals will also increase the risk of developing lung cancer.
Passive smoking, or inhaling tobacco smoke from other smokers who may be sharing a living space with an individual, is also another established risk factor for developing lung cancer. Researchers have discovered that non-smokers who live with a smoker have a 24% increase in risk for developing lung cancer as compared to non-smokers.
Radon gas is a natural, chemically inert gas that is the byproduct of the decay of uranium. This gas is known to cause lung cancer, with an estimated 12% of cancer deaths attributable to radon gas annually in the United States. This makes radon the second leading cause of lung cancer in the US. If an individual also smokes this will greatly increase the risk of developing lung cancer. Radon gas will travel through the soil and enter homes through gaps in the foundation, pipes or a sump pump drain. The US Environmental Protection Agency believes that one out of every 15 homes has dangerous levels of radon gas. This gas is odorless and invisible but is easily detected with simple test kits. Once it is determined that a home has radon gas effective solutions are available in order to mitigate the levels of gas in the home.
If a person has other lung diseases, most notably chronic obstructive pulmonary disease, they also carry an increased risk for developing lung cancer even after the effects of cigarette smoking has been excluded. There have been numerous studies that have shown that lung cancer is more likely to occur in both smoking and non-smoking relatives of people who have had lung cancer than in people in the general population. This means that there is likely other individual genetic susceptibilities which play a role in the risk factors for lung cancer.
Any prior history of lung cancer will also increase the risk of a person developing a second tumor over and above the general population who develop a second cancer. Researchers have also linked the development of lung cancer to air pollution from vehicles, industry and power plants in exposed individuals. This risk factor may fall under the category of air and job pollution. Up to 1% of lung cancer deaths can be linked to breathing polluted air.