Smoking is not considered a major risk for breast cancer, and overall, it may present no risk at all. But some studies have suggested that smoking may increase the risk of breast cancer in certain women. A study published in the November 18, 2002, issue of the British Journal of Cancer analyzed data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women who did not have breast cancer. It concluded that smoking had little or no independent effect on the incidence of breast cancer. But there appear to be some exceptions:
- A study published in the October 5, 2002, issue of The Lancet suggested that teenage girls who smoke increase their risk of developing breast cancer before menopause. The risk doubles for women who started to smoke within five years of starting to menstruate. By age 50, women who began smoking as teens had a risk of breast cancer that was 80-percent higher than if they had not begun to smoke so early in life.
- Women who have a family history of breast and ovarian cancer may increase their own risks if they smoke, according to results of a study published in the April 2001 issue of Cancer Epidemiology Biomarkers & Prevention.
- Women who smoke and develop breast cancer are more likely than other women to develop a more aggressive form of the disease (called "hormone receptor negative") that isn't as easy to treat as the more common type and also tends to have a poorer prognosis. Results of a study published in the January 2, 2001, edition of the International Journal of Cancer suggested that this type of breast cancer is twice as likely to occur among present and former smokers than among women who never smoked.
Whatever your personal risk of breast cancer, please bear in mind that lung cancer will kill 68,510 American women this year, more than breast and ovarian cancer combined. You also should know that almost 90 percent of all lung cancer that occurs in women is caused by smoking, and that women are 1.5 times more likely to develop lung cancer than men are. And don't forget that smoking also increases your risk of heart disease, the number-one killer of women.
Andrew Weil, M.D.