By Lisa Rapaport
(Reuters Health) – Long-time smokers may face an increased risk of death if they develop breast cancer, according to a Japanese study that adds to a growing body of evidence highlighting the lethal effects of cigarettes.
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.
p> Fewer years of smoking were moreover linked to an increased risk of death from breast cancer, yet the extra risk was so small that it might have been due to chance.
Other studies have explored the connection between smoking & survival among breast cancer patients, yet 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, a breast oncologist at Miyagi Cancer Center Hospital in Japan, in email to Reuters Health.
Worldwide, breast cancer is the most usual malignancy in women. About one in nine women will eventually develop it, according to the National Institutes of Health. The risk increases with age, from 1 in 227 at age 30 to 1 in 26 by age 70. Factors such as obesity, inactivity, alcohol use or early menstruation can increase the risk.
For the current study, Kawai & colleagues followed 848 women who were treated at the Miyagi Cancer Center Hospital between 1997 & 2007 for newly diagnosed breast cancer.
Women who described themselves as current smokers were typically younger when their breast cancer was diagnosed, approximately 49 years old on average, compared with 53 for women who claimed to be former smokers & 58 for nonsmokers.
The current smokers moreover tended to weigh less, have more advanced tumors, & have fewer health complications than the other women in the study.
With half of the women in the study followed for at least seven years, the researchers saw 170 deaths from all causes â€“ including 132 deaths from breast cancer.
Roughly one third of the women hadnâ€™t yet gone through menopause when they started the study. In this subset, those who had smoked for more than approximately 21 years were three times more likely to die of any cause, & nearly three & a half times more like to die of their breast cancer, than those who never used cigarettes.
Researchers moreover examined exposure to second-hand smoke among women whose husbands were current or former smokers & found no significant impact on the womenâ€™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 approximately their exposure to cigarettes, the researchers acknowledge in the journal Cancer Science. The study moreover lacked data on second-hand smoke that didnâ€™t come from the womenâ€™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 & Stanford University School of Medicine.
â€œThere are now quite a few studies suggesting that active smokers diagnosed with breast cancer have poorer survival â€“ not to mention accumulating evidence that smokers may have a greater risk of developing breast cancer,â€ Reynolds, who wasnâ€™t involved in the study, said by email.
This study, however, didnâ€™t look at whether smoking causes breast cancer.
Even if not all of the evidence is conclusive, it should still be enough to motivate patients to abandon cigarettes, said Mia Gaudet, strategic director of breast & gynecologic research at the American Cancer Society in Atlanta, in an email.
â€œRegardless of whether or not a woman has breast cancer, quitting smoking is likely to be the best lifestyle alter a woman can make to improve her health,â€ she said.
SOURCE: http://bit.ly/1TOoirO Cancer Science, online July 14, 2015.