Photo: Getty Images
Lung cancer is the leading cause of cancer mortality in U. S. females. The American Cancer Society estimates 71,340 deaths from lung cancer in American women in 2011. For men, the number is only slightly higher at 85,600.
Christina S. Baik of Tufts Medical Center, Boston, Massachusetts, and colleagues studied the characteristics of female lung cancer based on the Nurses' Health Study, which included 121,700 female U. S. nurses.
“There is increasing evidence that lung cancers in women are biologically distinct from those of men,” Baik wrote. Women are more likely to develop the adenocarcinoma type of lung cancer, and adenocarcinoma cancers in women are more likely to include mutations in the epidermal growth factor receptors, which respond to targeted chemotherapy. In addition, women with lung cancer are more likely than men to be lifelong nonsmokers.
Baik identified 1,729 cases of lung cancer in the Nurses' Health Study. Of these cases, 8 percent occurred in women who never smoked. Current smokers accounted for 45 percent of lung cancers, and former smokers developed the remaining 47 percent.
Female hormones including estrogen may have a small effect on lung cancer risk, according to Baik's results. Menopause before age 44 and oral contraceptive use for at least five years were associated with increased risk.
Lung cancer statistics are different in Europe. Isaura Parente Lamelas and colleagues in Spain studied lung cancer in 1,290 patients admitted to a single hospital between 1999 and 2006. Of these cases, only 14.7 percent were women. Unlike their American counterparts, 83 percent of the Spanish women with lung cancer had no history of smoking. There was no difference in survival between men and women in this group.
Research into the role of estrogen may offer improvements in lung cancer therapy, according to a report by Susan E. Olivo-Marston at the National Institites of Health and colleagues. They found a significant association between above average levels of estrogen in the blood and poor prognosis for lung cancer patients, both women and men.
1. American Cancer Society. Cancer Facts and Figures 2011. Web.