More Evidence Smoking Raises Risk of Death From Breast Cancer
(Reuters Health) – Long-time smokers may face an increased risk of death if they develop breast cancer, according to a study from Japan.
Among more than 800 women with breast cancer, those who had smoked for more than two decades had at least triple the odds of dying of any cause, or from breast cancer in particular, compared with women who never used cigarettes.
Fewer years of smoking were also linked to an increased risk of death from breast cancer, but not to a statistically significant extent.
Other studies have explored the connection between smoking and survival among breast cancer patients, but the current research is among the first to assess the impact of the duration of smoking on outcomes for women with this type of tumor, said study co-author Dr. Masaaki Kawai of Miyagi Cancer Center Hospital, in email to Reuters Health.
Dr. Kawai and colleagues followed 848 women who were treated at the Miyagi Cancer Center Hospital between 1997 and 2007 for newly diagnosed breast cancer.
Women who described themselves as current smokers were typically younger when their breast cancer was diagnosed, about 49 years old on average, compared with 53 for women who claimed to be former smokers and 58 for nonsmokers.
The current smokers also tended to weigh less, have more advanced tumors, and have fewer health complications than the other women in the study.
With a median follow up of seven years, the researchers saw 170 deaths from all causes – including 132 deaths from breast cancer.
Roughly one third of the women were premenopausal at diagnosis. In this subset, those who had smoked for more than 21 years were three times more likely to die of any cause, and nearly three and a half times more like to die of their breast cancer, than those who never used cigarettes.
Researchers also examined exposure to second-hand smoke among women whose husbands were current or former smokers and found no significant impact on the women’s risk of death from any cause or from breast cancer specifically.
One limitation of the study is its reliance on patients to accurately report information about their exposure to cigarettes, the researchers acknowledged online July 14 in the journal Cancer Science. The study also lacked data on second-hand smoke that didn’t come from the women’s spouses.
Even so, the findings add to a growing body of research pointing to the specific risks smoking poses for women with breast cancer, said Peggy Reynolds, a researcher at the Cancer Prevention Institute of California and Stanford University School of Medicine.
“There are now quite a few studies suggesting that active smokers diagnosed with breast cancer have poorer survival – not to mention accumulating evidence that smokers may have a greater risk of developing breast cancer,” Reynolds, who wasn’t involved in the study, said by email.
Cancer Science 2015.