June 1, 2004 -- Women have no higher lung cancer risk than men, according to a worldwide panel of researchers. But both men and women need to quit smoking to improve their odds of survival, the researchers say.
Their report appears in the June 2 issue of the Journal of the National Cancer Institute.
"Women do not appear to have a greater susceptibility to lung cancer than men, given equal smoking [habits]," writes lead researcher Chris Bain, PhD, an epidemiologist with the University of Queensland in Brisbane, Australia.
However, not everyone is convinced. One cannot dispute evidence that women -- including nonsmokers -- have higher rates of lung cancer than male nonsmokers, writes William J. Blot, PhD, an epidemiologist with Vanderbilt University Medical Center in Nashville, in an accompanying editorial. He calls for further investigation of these differences.
"The possibility remains that some differences in the way females and males are exposed to and/or respond to carcinogenic agents do exist," Blot writes.
Short History of Smoking/Lung Cancer
It is indeed a controversial issue, notes Blot. Early studies of the smoking/lung cancer link involved men almost exclusively, he points out. When risks among female smokers were first reported, the risks tended to be lower than for men -- not unexpected, since women typically start smoking later in life, and smoke fewer cigarettes on a daily basis, he explains.
However, in the 1990s, several studies indicated that among women and men who were long-time smokers lung cancer risk was higher for women. Researchers began to look for reasons. Are there biological differences in how men and women's bodies metabolize or detoxify nicotine? Could female hormones affect lung tumor growth?
In this report, Bain's research group analyzed data from more than 60,000 women and 25,000 men who participated in two major studies. After taking into account each person's age, daily smoking habits, age when each began smoking, and time since quitting, researchers found no difference between men's and women's lung cancer risk.
Bain's research group didn't stop there. It reviewed six additional studies that examined lung cancer risk and found that among men and women with similar smoking habits women didn't have a higher susceptibility to lung cancer than men.
Gender-Specific Type of Lung Cancer?
However, the data do suggest that a specific type of lung cancer may be more prevalent in women -- even though women's risk is no different, Bain writes.
Indeed, it is "noteworthy" that the researchers found a 33% higher rate of lung cancer among nonsmoking females than in similar nonsmoking males, Blot adds.
In his editorial, Blot calls for further research into the biological underpinnings of this trend. In the meantime, it's important to get the "stop smoking" message to both men and women, he writes.
SOURCES: Bain, C. Journal of the National Cancer Institute, June 2, 2004: vol 96, pp 826-834. Blot, W. Journal of the National Cancer Institute, June 2, 2004: vol 96, pp 812-813. WebMD Medical News: "Smoking Seems More Harmful to Men Than Women."