TUESDAY, July 11, 2006 (HealthDay News) -- Women who smoke are more likely to develop lung cancer than men who smoke.
However, women smokers are less likely to die of the disease than their male counterparts, according to new research.
Reactions to the findings, published in the July 12 issue of the Journal of the American Medical Association, were slightly circumspect.
"It's not absolutely brand new information, but it's important," said Dr. Norman Edelman, chief medical officer of the American Lung Association.
Dr. Michael Thun, vice president of epidemiology and surveillance research at the American Cancer Society, said in a statement, "This report is based on a secondary analysis of data from a clinical trial designed to assess whether screening people at high risk for lung cancer with helical CT [computed tomography] can improve survival ... The trial was not designed to address the question that is of greatest interest in this report -- whether women are more susceptible than men to the carcinogens in tobacco smoke."
Lung cancer remains the leading cancer killer of both men and women in the United States, according to the American Cancer Society. An estimated 73,000 women and 90,500 men will die of the disease in 2006. Among women, lung cancer is responsible for more deaths than breast and colon cancer combined.
Part of the problem is there's no sure way to detect lung cancer early.
"Lung cancers get detected every which way," Edelman said. Sometimes symptoms, which indicate advanced disease, are the tip-off. Other times, X-rays taken for other reasons point up lung cancer, he said.
Spiral CT screening is a promising technology on the horizon but is not yet proven. According to Edelman, Dr. Claudia I. Henschke, of Cornell University and corresponding author of the new study, is a leading proponent of the technology.
Henschke and her colleagues looked at 7,498 women and 9,427 men aged 40 and older who had a history of cigarette smoking. All participants were screened using computed tomography for lung cancer between 1993 and 2005.
Lung cancer was diagnosed in 2.1 percent of the women and 1.2 percent of the men. And while women were roughly twice as likely to have lung cancer, they were only 48 percent as likely to die of the disease. The results remained consistent even after the researchers compensated for factors such as years of smoking, disease stage, and tumor cell type.
The authors could not explain why such a difference between the sexes might exist.
Thun pointed to several limitations of the study, one being that no distinction was made between new lung cancers and ones that had been present but gone undetected. Because women have a higher prevalence of slow-growing tumors than men, this could have skewed the results, he said.
Also, the only people allowed into the trial were those considered likely to survive surgery, another potential bias, Thun said.
According to the study authors, the results point to a need to direct more aggressive anti-smoking efforts at women and girls, and possibly to screen women who are smokers at an earlier stage.
The question is how to screen.
"There's no gold standard now for screening for lung cancer, no even decent method for screening," Edelman said. "There's no question that spiral CT will pick up lung cancer earlier than anything else, but it picks up so much benign disease, and we don't know if operating on all those will wash out the benefit."
"We really do need early detection, and it may be spiral CT," he added. "I'm not saying it's not, but it's not rock solid yet."
For much more on lung cancer, visit the U.S. National Cancer Institute.