Breast cancer is the type of cancer most closely linked with women in the public consciousness, but lung cancer has now surpassed it as the leading cause of cancer deaths among women. According to a report published today in the Journal of the American Medical Association, fatalities for females suffering from the disease are up 600 percent since 1930, whereas the number of men who died of lung cancer over the same time period declined. The researchers suggest that future studies of the etiology of lung cancer need to include more women and take gender-related differences into account.

In 2003 80,100 women in the U.S. were diagnosed with lung cancer--a 60 percent increase from 1990--and 68,800 of them died. Over the same time period, the number of new cases among males was constant. Much of the discrepancy can be attributed to differences in smoking behavior, Mark G. Kris of Memorial Sloan-Kettering Cancer Center and his colleagues report. Since the 1960s, the number of male smokers has decreased by about half, whereas the number of female smokers declined by only 25 percent. In addition, the disease behaves differently in some female patients, leading to increased protein expression, decreased rates of DNA repair and increased incidence of mutation in specific genes. "Many of these women stopped smoking 20 years ago yet still get cancer," Kris says. "However, their response to some targeted therapies is more favorable than men and we are trying to figure out why."

In the U.S. lung cancer now kills as many women as breast cancer and all gynecological cancers combined. "The extraordinary increase in lung cancer rates seen among U.S. women in the 20th century will be repeated among women in developing countries during this century unless effective tobacco control measures are implemented," the team concludes. "Curtailing the increase in tobacco use among women in developing countries represents one of the greatest opportunities for disease prevention in the world today."