Active smoking and second-hand smoke linked to breast cancer

April 23, 2009 By Paul Cantin

There is now enough scientific evidence to link both active smoking and second-hand smoke to breast cancer, according to an international panel convened by the Ontario Tobacco Research Unit, an affiliate of the Dalla Lana School of Public Health, University of Toronto, with support from the Public Health Agency of Canada.

"Until recently, evidence about the link between breast cancer and tobacco smoke, although voluminous, was inconclusive. But the panel's careful analysis of all available evidence, particularly recent evidence, led us to conclude that there is persuasive evidence of risk," said Neil Collishaw, chair of the panel. "An estimated 80 to 90 per cent of women have been exposed to tobacco smoke in adolescence and adulthood. Those women face an increased risk of breast cancer because of that exposure."

There have been many studies over the years on the relationship between cigarette smoke and breast cancer in women. The panel comprehensively reviewed all available evidence, including important recent evidence, and concluded there was a risk even non-smoking young women face through passive exposure to cigarette smoke. The panel also concluded that the relationship of active smoking to both pre- and post-menopausal breast cancer is consistent with causality, but there is not yet enough evidence to draw a conclusion about the nature of the relationship between exposure to second-hand smoke and breast cancer for older, post-menopausal women.

"It is important from a public health perspective to get the message out to the public, and young women in particular, that available evidence shows that both active smoking and exposure to passive smoke increase the risk of breast cancer," said Professor Anthony Miller, a panelist.

Prior to collaborating on the report released today, the expert panel met on November 10 and 11, 2008 in Toronto as part of the conference Tobacco Control for the 21st Century: Challenges in Research and Evaluation, organized by the Ontario Tobacco Research Unit (OTRU).

Provided by University of Toronto (news : web)