Lung cancer rates among white and Hispanic women born since the 1960s are on the rise, according to a new study published in the New England Journal of Medicine. Why these rates are climbing faster among women than men, however, remains unclear.
The authors studied data from North American Association of Central Cancer Registries on invasive lung cancers diagnosed between the years 1995 and 2014. All U.S. states were included in the data but four: Kansas, Maryland, Vermont and Minnesota.
Overall, the authors found that invasive lung cancers have “generally decreased” among men and women of all races and all ethnic groups from ages 30 to 54. Those drops have been the most significant among men.
One attention-grabbing finding from the group’s research is that lung cancer is more prevalent in women than in men among the country’s white and Hispanic populations. For example, among whites between the ages of 40 and 44, the female-to-male incidence rate ratio was 0.88 from 1995-1999 and 1.17 in 2010-2014. And among Hispanics in the same age group, the female-to-male incidence rate ratio was 0.79 from 1995-1999 and 1.22 in 2010-2014.
The authors explained that the smoking habits of these men and women don’t fully explain the differences in cancer rates.
“The prevalence of smoking among white women born after the 1970s and among Hispanics born after the 1960s approached, but did not exceed, that among their male counterparts,” wrote lead author Ahmedin Jemal, DVM, PhD, of the American Cancer Society, and colleagues. “Moreover, the average number of cigarettes smoked per day continues to be considerably lower among women than among men. Women are more likely than men to smoke menthol cigarettes, which are not associated with a higher risk of lung cancer than nonmenthol cigarettes. Furthermore, the use of tobacco products other than cigarettes, such as cigars and smokeless tobacco (e.g., chewing tobacco), has been much lower among women than among men.”
Jemal et al. went on to explore these statistics further, looking at causes of lung cancer not associated with tobacco.
“Occupational exposure to lung carcinogens, such as asbestos and arsenic, which have synergistic effects with smoking and were historically more common among men than among women, have decreased dramatically over the past several decades," the authors wrote. "This may have contributed to the steeper decline in lung cancer among men. Although exposure to secondhand smoke has also decreased substantially over the past several decades, the decline has not been shown to differ significantly between men and women.”
Another potential clue for the difference in incidence rates is related to medical imaging: more indolent lung tumors are being found through CT screening in women than in men.
Though the “why” is still unclear, Jemal and colleagues concluded that their findings have “important implications for public health” and more research is necessary.
“It may foreshadow a higher future burden of overall lung cancer among women than among men as younger cohorts age, which further underscores the need to intensify antitobacco measures to decrease smoking among young women,” the authors concluded. “Our finding also calls for continued monitoring of sex-specific risks of lung cancer and for etiologic studies, including studies of sex differences in smoking-related susceptibility to lung cancer, to identify reasons for the higher rates of lung cancer among young women.”
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.