High Rates of Lung Cancer Found for Female Non-smokers

New research shows that about 20% of the women who get lung cancer have never smoked. The figure for men is about 8%. These figures are higher than was previously thought.

The figures for smokers, though, remains much higher, with current smokers being 10 to 30 times more likely to get lung cancer than people who have never smoked.

The study, done by researchers at Stanford University School of Medicine and the Northern California Cancer Center, will be published in the February 10th issue of the Journal of Clinical Oncology. The researchers analyzed data that tracked the incidence in lung cancer in over a million people in the United States and Sweden.

Ellen Chang, ScD, co-author of the study, said she thought it was likely that many of the cases of lung cancer in those who never smoked could be attributed to second-hand smoke. That might also explain some of the gender differences that the study found. Because more men smoke than women, women may be more likely to be exposed to second-hand smoke.

Lead author Heather Wakelee, MD, said that some environmental pollutants, including asbestos, chromium, arsenic and radon, are also believed to cause lung cancer in people who have never smoked, but that hasn't been conclusively proven. More research is needed. Eventually, doctors will be able to understand how the cancer works on a molecular level, which, she hopes, will lead to the discovery of new treatments.

Dr. Wakelee also hopes that the studies will help to lessen the stigma associated with lung cancer. "I have a lot of patients who have never smoked," she said. "And because of the stigma, people are embarrassed to speak out about their disease. They feel like as soon as they say they have lung cancer, everyone judges them."

The stigma affects not only patients, but also funding and other support for research, Dr. Wakelee said. Although more than 180,000 Americans are diagnosed with lung cancer every year, and although lung cancer kills more patients than breast, colon and prostate cancers combined, it does not have the visible support that some other diseases do. Dr. Wakelee says she hopes that some day the symbol for lung cancer support -- a clear ribbon -- will be easily recognized.

Chang said that "non-smoking-associated lung cancer is an increasingly important issue even if only because the population of never-smokers is growing."

Sources

Many lung cancer cases in nonsmokers: study, by Maggie Fox, Feb. 9, 2007, Reuters

Lung Cancer Rates Higher Among Female Non-Smokers Than Previously Thought, Stanford Study Shows, Feb. 8, 2007, Business Wire press release