University of California San Francisco
Helen Diller Family Comprehensive Cancer Center

Smoking Is Associated with More Deaths among Women with Breast Cancer

By Jeffrey Norris, UCSF Science Cafe | November 9, 2010

D.BraithwaiteWomen who feel they need another good reason to quit smoking might want to consider their breast cancer risk.

Those afflicted with breast cancer who smoke or who have smoked in the past are much less likely to survive the disease, according to a new study by UCSF epidemiologist Dejana Braithwaite, PhD.

Braithwaite, presenting her preliminary results at the American Association for Cancer Research's annual "Frontiers in Cancer Prevention" meeting in Philadelphia on Nov. 8, reported that smokers or former smokers diagnosed with breast cancer were about 40 percent more likely to die as a result of the disease than women who had never smoked.

The study included 2,265 woman diagnosed with breast cancer. After diagnosis women were surveyed about smoking and followed to keep track of their health status. The median time of follow-up was nine years. During follow-up 164 of the women died from breast cancer, while 120 died from other causes. The results were independent of age, education, tumor characteristics and post-operative treatment.

The association in the study between smoking and a greater likelihood of death due to breast cancer was even larger among women diagnosed with a type of cancer called HER2-negative breast cancer. The preliminary findings suggest that women with HER2-negative breast cancer who smoked at the time of diagnosis or at some point in time prior to diagnosis were roughly 60 percent more likely to die from the disease in comparison to women who never smoked.

In addition, smokers with breast cancer were twice as likely to die from causes other than breast cancer. "It is unclear," Braithwaite said, "whether there is an association between smoking and life expectancy following breast cancer diagnosis that works through affecting non-breast cancer causes of death."

Read more at Jeffrey Norris, UCSF Science Cafe