Smoking Linked to Breast Cancer Spread

Breast cancer patients who smoke have a much higher risk of the disease spreading to their lungs than do nonsmokers, according to a new study released today.

Researchers at the University of California, Davis, School of Medicine and Medical Center found that women whose breast cancer had spread to the lungs were twice as likely to be smokers than women whose breast cancer had not spread.

The study, conducted by Dr. Susan Murin, an associate professor of medicine at the university, and John Inciardi, a statistician at the university, monitored 87 patients with invasive breast cancer that had spread to the lungs.

Researchers compared them with 174 women with breast cancer that had not spread. Each was matched by year of diagnosis, age at diagnosis, size of primary tumor and whether cancer was found in the lymph nodes.

Study Supports Earlier Studies

The findings, published in the June issue of the journal Chest, support earlier studies linking smoking to a higher risk that a breast cancer will spread to the lungs or that women who smoke are more likely to die of breast cancer than nonsmokers.

"Women are in many ways more frightened of breast cancer than lung cancer, because it's so much more common. Everyone knows someone who has breast cancer," Murin said in a statement.

"But women are more likely to survive breast cancer if they don't smoke. If we can let them know that, it might motivate some women to quit."

Murin said other lifestyle factors, such as diet and exercise, may also play a role in the interplay between smoking, breast cancer and the spread of cancer to the lungs.

"Smokers generally have less healthy diets and tend to exercise less than their nonsmoking counterparts," Murin said in the statement. "We need to further study this relationship."