June 1, 2009 - The risk of lung cancer induced by smoking has been recognized since 1955. At first the tobacco companies resisted the scientific community's objective evidence but with time and persistent advocacy by scientists, everyone accepted the association of cancer, heart disease and lung disease caused by tobacco use.
During the ensuing decades, researchers have endeavored to isolate the noxious chemicals in tobacco that cause disease. Some early thoughts were to find the offending chemicals so these agents could be removed. More recently, however, finding these compounds in the urine of smokers has resulted in the ability to determine who is at higher risk to develop lung cancer.
Interestingly, only one in ten smokers will get lung cancer. Determining who could be that “one” person is an important motivator for the 10% at risk to stop smoking if they want to live. “Urinary levels of tobacco-specific nitrosamine metabolites in relation to lung cancer development in two prospective cohorts of cigarette smokers,” was an abstract shared recently by Dr. J. .M. Yuan during proceedings of the 100th Annual Meeting of the American Association for Cancer Research.
Dr. Yuan and his associates developed a test for a known carcinogen (cancer causing chemical) called 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol—also known by the much simpler moniker, NNAL. The researchers took blood and urine samples from over 80,000 Chinese and Singaporeans from 1986 to 1999 and measured the levels of NNAL. These researchers then patiently followed the smokers over the ensuing years to see which 10% of the smokers developed lung cancer.
The conclusions are interesting and again support the fact that smoking causes cancer. The risk of lung cancer was 8.5 times greater in those who had the highest levels of nicotine and NNAL. The challenge now is to make the test inexpensive and easy to obtain so that smokers can be screened. The researchers say this test is not yet ready for general clinical use.
Why do some smokers have a higher level of NNAL and get lung cancer while other smokers survive? The scientists are still searching for the answer to this question. The leading theory at this time is that some smokers have a genetic make up that breaks down the toxins in tobacco differently than other smokers. If a smoker can get rid of the toxins quickly, the overall exposure is less and, presumably, the chances of survival are better.
Bottom line: don't smoke, but if you do—or did in the past— the opportunity to know whether you have a high level of NNAL will help predict whether you are at a higher risk for lung cancer. Knowing you are at risk should make you more vigilant for early detection of lung cancer and ultimately improve your chances of survival.
Dr. Allen Weiss is CEO & President of the NCH Healthcare System. He is board certified in Internal Medicine, Rheumatology and Geriatrics, and was in private practice in Naples, Florida from 1977 - 2000. Dr. Weiss is active in a variety of professional organizations and boards, and has been published in numerous medical journals, including the American Journal of Medicine and the Journal of Clinical Investigation.