Smoking is not normally associated with breast cancer but the link is growing stronger. In the current issue of The Breast Journal is a study of 6000 women diagnosed with breast cancer between 1970 and 2006. The women were separated into three groups: women who have never smoked, former smokers and current smokers. Current smokers were more likely to have been diagnosed with breast cancer at an earlier age (52) then either former smokers (age 55) and never smokers (age 56). The association was only shown in Caucasian women and not in African Americans.
Previously, The Mayo Clinic has reported that a history of smoking even 100 cigarettes in a woman's lifetime increases the risk of breast cancer. The Fred Hutchinson Cancer Research Center also has reported that women with breast cancer that to continue to smoke have a 120% increased risk of developing a second breast cancer. The use of alcohol and obesity also were associated with this increased risk.
Stanton Glanz, PhD. from the University of California in San Francisco states that earlier studies of smoking and breast cancer, did not research whether non-smoking women were exposed to secondhand smoke. Once exposure to secondhand smoke was factored into previous studies, smoking was related to a 2 times higher risk of developing breast cancer and women exposed to secondhand smoke had a 1.7 times higher risk than women who have never smoked and are not exposed to secondhand smoke. This effect was seen in pre-menopausal women that have never been pregnant.
Animal studies have shown that 20 harmful chemicals in tobacco smoke are found in the breast tissue and breast milk of smoking women. Further studies are needed to see if smoking is a causative factor in breast cancer.