People who smoke tend to have a greater risk of death once they're diagnosed with lung cancer compared to those who don't light up, find Florida doctors in a recent study.1 Not only are there differences in survival rates between the two groups, but certain patient characteristics are unique, as well, say physicians with the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida.
Lung cancer, known medically as adenocarcinoma of the lung (ADD-en-oh-car-sin-oh-muh), is the leading cancer killer in both men and women. In 2002, it was estimated that nearly 170,000 new cases of the disease would be diagnosed in the U.S.2 Risk factors include cigarette, cigar, and pipe smoking; exposure to secondhand smoke; exposure to radon gas; and exposure to asbestos.3 While lung cancer and diseases like idiopathic pulmonary fibrosis (IPF) are pathologically different, experts say lung cancer can be a complication in people diagnosed with IPF.4,5
Better Odds for Non-Smokers
In their study, George Simon, MD, and his colleagues wanted to determine if there were differences in the odds of survival for smokers diagnosed with lung cancer as compared to those who don't smoke. They analyzed that information, as well as other patient characteristics, in 132 non-smokers treated for lung cancer at their clinic, comparing the results to data from smokers with the disease, also treated at the cancer center.
Simon and his team learned that there were significant differences in the survival odds between the two groups. Smokers faced a 5-year survival rate of just 16% compared to 23% over the same time span in those without the habit. "Smoking was identified as an independent negative prognostic factor," they wrote.
When analyzing patient characteristics, the researchers found that the average age of smoking patients at diagnosis was lower compared to non-smokers (63.5 years v 59.4 years), and there was a larger percentage of women in the group that never smoked, they found. "Our data show that never-smokers with adenocarcinoma are predominately female, present at a higher mean age, and have improved survival when compared to current smokers," Simon and his associates wrote.
Pathological Differences
Simon said that lung cancer in nonsmokers exhibits a unique behavior, which is why survival odds are better. Lung cancer in smokers is derived directly from the carcinogenic properties of cigarette smoke, he said, whereas non-smoking-derived lung cancer possesses its own unique pathological characteristics and behavior.
These distinct pathological characteristics "warrant further investigation" focusing specifically on the differences, Simon and his team wrote.
In an editorial accompanying the analysis in the journal Chest, doctors at the Cleveland Clinic Foundation concurred with the findings. Peter Mazzone, MD, and his colleagues further underscored the need to classify patients with lung cancer in future clinical research to help contribute to the body of evidence that exists.
1. Nordquist LT, Simon GR, Cantor A, Alberts WM, Bepler G. Improved survival in never-smokers vs current smokers with primary adenocarcinoma of the lung. Chest 2004 Aug;126(2):347-51.
2. American Lung Association. Facts About Lung Cancer.
3. National Cancer Institute. National Institutes of Health (NIH). Lung Cancer: Who's at Risk?
4. Yoshimura A, Kudoh S. Idiopathic pulmonary fibrosis and lung cancer [in Japanese]. Gan To Kagaku Ryoho 2003 Feb;30(2):215-22.
5. Ma Y, Seneviratne CK, Koss M. Idiopathic pulmonary fibrosis and malignancy. Curr Opin Pulm Med 2001 Sep;7(5):278-82.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
