Approximately 160,000 cases of lung cancer are diagnosed annually in the United States alone—about 450 cases on any given day. A little more than 90% of all lung cancers are linked with cigarette smoking.
In the past 40 years the prevalence of smoking in the U.S. has dramatically reduced; smokers are giving up the habit and fewer young people are taking up smoking. However, even among those who have quit, health risks associated with past smoking remain. That explains the reason that approximately 50% of the 160,000 cases of lung cancer diagnosed annually are made among former smokers.
While many in the scientific community have encouraged smokers to quit, alleging that the health effects of smoking are reversible shortly after cessation, regardless of the duration or intensity of smoking exposure, this is not true.
Smoking for about 25 years appears to trigger a biological change that promotes the growth of lung cells towards the development of lung cancer—even after the smoker quits. While quitting smoking if still the best possible option at any age, damage to the respiratory system may continue to plague the ex-smoker for years after quitting—even leading to lung cancer.
Smokers of one pack a day for twenty or more years have a ten-to fifteen-fold greater risk of lung cancer than those who have never smoked. The more a person smokes or smoked in the past, the greater the risk of lung cancer and other smoking-related diseases. Every year a one-pack-a-day smoker smears the equivalent of a cup of tar over his or her respiratory tract. This can cause a variety of adverse effects, some of which can be reduced-but not entirely reversed--by quitting.
The advice for current smokers: Quit Now. Get help if necessary. Even if you have been smoking for decades you will be receive some health benefits, especially a rapid decline in risk from the number one cause of cigarette death: cardiovascular disease. As for your elevated risk of lung cancer, long-term smokers who quit ten or more years ago do have a personal risk of developing lung cancer below the 10%-15% range of continuing smokers.
Should smokers and former smokers have regular chest x-rays? Talk it over with your doctor, but be aware that chest x-rays may not assist in diagnosing lung cancer at an early curable stage. The American Cancer Society no longer recommends annual x-rays for smokers. There is some interest in the use of lower-dose CT scans to enhance detection of early-stage lesions. Several studies are now being carried out to determine if this technique will lead to an improvement in the survival rate of lung cancer patients. These CT type tests can yield many “false positives,” causing needless anxiety and sometimes needless surgery. And, unfortunately early detection of lung cancer has not proven to be helpful in saving lives from this disease.
For more information:
http://www.nhlbi.nih.gov/index.htm
http://www.cancer.org/docroot/home/index.asp
http://www.ACSH.org.
http://thescooponsmoking.org/