Smoking Increases Death Risk For Women With Breast Cancer

(Ivanhoe Newswire) — In a large prospective cohort study, it was reported that current smokers ““ or those with a history of smoking ““ drastically increased the risk of breast cancer progression in addition to overall death among multiethnic women with breast cancer.

"We found that women who are current smokers or have history of smoking had a 39 percent higher rate of dying from breast cancer, even after we took into account a wide array of known prognostic factors including clinical, socioeconomic and behavioral factors," which Dejana Braithwaite, Ph.D, assistant professor, division of cancer epidemiology, department of epidemiology and biostatistics at the University of California, San Francisco was quoted as saying.

In due course, smoking is associated with lung cancer and moreover implicated in various other cancers, however, it is unclear what affect smoking has on breast cancer, according to Braithwaite.

"We know that smoking is associated with a lot of diseases, from lung cancer to heart disease, but the association with breast cancer is still somewhat controversial," which researcher Christopher I. Li, MD, PhD, of the Fred Hutchinson Cancer Research Center in Seattle, was quoted as saying.  "Certainly, the association between smoking and breast cancer is nowhere near as strong as the association between smoking and lung cancer, but breast cancer may be another disease to add to the long list of serious health issues related to smoking."

Even though smoking may not be a direct cause of breast cancer, tobacco use increases the risk of death among the women who already have the disease.

“Specifically, it is unclear how long women live following breast cancer diagnosis and whether smoking increases the risk of death because of breast cancer progression or whether there is an association between smoking and life expectancy following breast cancer diagnosis that works through affecting non-breast cancer causes of death,” Braithwaite adds to the debated topic.

Consequently, Braithwaite and a team of researchers set out to examine the associations between smoking and the risk of death due to breast cancer progression or non-breast cancer related causes of death.

The group of investigators enrolled 2,265 multi-ethnic women diagnosed with breast cancer between 1997 and 2000 ““ following them for an average of nine years.  Researchers examined whether smoking affected death from breast cancer, non-breast cancer related causes and death from all causes.

"Specifically, it is unclear how long women live following breast cancer diagnosis and whether smoking increases the risk of death because of breast cancer progression or whether there is an association between smoking and life expectancy following breast cancer diagnosis that works through affecting non-breast cancer causes of death," Braithwaite said.

Results showed that 164 deaths from breast cancer and 120 deaths from non-breast cancer causes occurred during follow-up.

Those women who had a history of smoking or who were current smokers additionally had a twofold-increased risk for dying from non-breast cancer related causes in comparison to women with breast cancer who had never smoked.

Analysis was further conducted to examine whether body mass index, molecular breast cancer subtype or menopausal status modified risk.  Women who were current or past smokers and moreover had a HER2-negative tumor subtype reported a 61 percent increased risk for breast cancer death compared with women who never smoked.  Smokers with a body mass index less than 25 kg/m2 had an 83 percent increased risk for breast cancer death, and postmenopausal women had a 47 percent increased risk for breast cancer death compared with those who never smoked.

"The implication of this research is that it is important for physicians to improve smoking cessation efforts, especially among women newly diagnosed with breast cancer, in order to improve breast cancer specific outcomes and overall health outcomes," Braithwaite said.

“One message women have gotten in the past is that “˜you must go for a mammogram, because we can do nothing to prevent breast cancer.’ That’s absolute nonsense,” which Dr. Anthony B. Miller, a member of the panel and associate director for research of the Dalla Lana School of Public Health at the University of Toronto, was quoted as saying.  “You can be more physically active. You can eat a good diet and avoid becoming overweight.  Do not drink heavily “” and do not smoke!”

SOURCE: The Ninth Annual AACR Frontiers in Cancer Prevention research Conference, 7 ““ 10 November 2010