Smoking Bad for Cancer Treatment
Breast Cancer Patients Lower Later Death Risk by Quitting
WebMD News Archive
Oct. 20, 2003 -- Smoking has been long suspected as a risk factor for breast cancer. But a new study shows even after being diagnosed, women who quit can significantly cut their risk of dying from the disease.
No studies have conclusively linked cigarette smoking to breast cancer. But last year, Canadian researchers reported in The Lancet that women who begin smoking within five years of starting menstruation are 70% more likely to develop breast cancer before age 50 than women who never smoked. The link existed regardless of how long the teens had continued to smoke, according to their analysis of cancer rates and smoking histories in 3,000 women.
This study and the present findings are important, because some past studies have suggested that smoking may actually reduce breast cancer risk in postmenopausal women. That's because smoking reduces estrogen activity that can stimulate the growth of breast cancer cells
In a new study presented Monday, which is the first study to examine the effects of smoking during early treatment for breast cancer, researchers found that women who continue to smoke while undergoing radiation or having other forms of treatment are 2½ times more likely to die later from their cancer than patients who never smoked, says researcher Khanh H. Nguyen, MD, of the Fox Chase Cancer Center in Philadelphia.
But when patients quit smoking before their treatment begins, they reduce their risk of dying from cancer within 10 years of their diagnosis to level of patients who never smoked.
"Our study suggests that smoking cessation remains an integral component in the comprehensive management of breast cancer," says Nguyen.
"Smoking sometimes influences treatment outcomes," Nguyen tells WebMD. "This is really good news, because it shows patients who have any smoking history that it's never too late to quit."
His study, presented at the annual meeting of the American Society for Therapeutic Radiation and Oncology, involved 1,039 nonsmokers and 861 smokers who have been undergoing treatment for breast cancer since 1970. He then measured their outcomes for an average of 5½ years.
Adjusting for factors such as the spread and control of the cancer with surgery and radiation treatments, his team found that women who continued to smoke were more than twice as likely to die within a decade after their treatment began compared with those who quit before treatment or who had never smoked.
"The message is, smoking is not a good thing, and discontinuing can have a positive impact -- even after a (breast cancer) diagnosis." says Bruce Haffty, MD, professor of therapeutic radiology at Yale University School of Medicine, in New Haven, Conn. He was not involved in Nguyen's research.
"Obviously, we would be reluctant to encourage people to smoke to reduce risk of breast cancer," says Haffty. "But this study shows that when you look at smoking as a single factor, it is not protective," he tells WebMD. "In fact, it worsened the outcome. When you look at overall survival, continuing to smoke has, as we would expect, a detrimental effect."
Of course, never starting is even better.