Mr. Chairman, members of the committee, I wish to thank you for your invitation to speak to you about the Breast Implant Cohort Study. I am Dr. Stachenko. I am Deputy Chief Public Health Officer responsible for the Health Promotion and Chronic Disease Prevention Branch of the Public Health Agency of Canada. I am happy that Dr. Yang Mao has been able to join us. He is Director of Health Promotion and Disease Prevention at the Centre for Chronic Disease Prevention and Control. He also takes part in the cohort study as a researcher.
The Breast Implant Cohort Study is the largest study ever designed to investigate the risk of cancer and other health outcomes in women with cosmetic breast implants. The first scientific results of this study are now available. As you are aware, an article on cancer incidence was published in English in December 2005 by the International Journal of Cancer. In response to the request of the clerk on May 11, 2005, we at the Public Health Agency have secured permission from the journal's publisher to translate the article and provide it to the committee in French. I understand that the French translation has been provided to her yesterday.
As well, a second article based on the study has been developed. It concerns the relative risk of mortality from breast cancer and from other causes. This article has been accepted by the American Journal of Epidemiology and is expected to be published within the month.
The Breast Implant Cohort Study involved identifying women in Ontario and Quebec who received implants for cosmetic purposes during the years 1974-1989, inclusively, as well as gaining access to their patient records. The study includes information from over 40,000 women aged 18 years and older. It brought together plastic surgery patients records from Quebec and Ontario and linked them to the National Cancer Registry Database maintained by Statistics Canada.
The women and physicians who participated in the study were assured that the study had passed rigorous scientific and ethical reviews.
Since the study was first announced, the frameworks for privacy, information protection, and information access have evolved significantly, both within the Government of Canada and in the provinces of Ontario and Quebec, from which the cohorts were drawn. This has considerably lengthened the time it took to gain access to patients' records and to link them to cancer data, beyond what had been originally foreseen. The study data set was completed in June 2003.
Starting in 2003, our epidemiologists and their colleagues in Quebec, Ontario, and academia have been able to undertake the epidemiological analysis and the development of scientific articles more rapidly than was anticipated.
The first article on cancer incidence found that women undergoing cosmetic breast augmentation do not appear to be at an increased long-term risk of developing cancer. Overall cancer incidence rates among women who received breast implants were similar to those of the other plastic surgery patients. In fact, women who received breast implants had lower breast cancer rates than other plastic surgery patients. As well, no increased risks were observed among the implant population at the other cancer sites examined.
As well, I can very briefly outline some of the key findings of the second article on mortality, which will soon be published. Overall, women who received breast implants for cosmetic purposes had lower mortality rates than those of the general population. A lower than expected number of deaths, mainly from cancer and cardiovascular diseases, accounted for most of this reduction. The article acknowledges that self-selection is a likely explanation for lower mortality rates; women who choose to undergo an invasive cosmetic procedure are, on average, likely to be in better health than the general population.
However, it is of note, and consistent with previous work, that increased rates of suicide were observed among women who received breast implants relative to the general population, but there were no statistical differences relative to other plastic surgery patients. The authors suggest that further studies that collect detailed risk factor data for suicides among both implant and other cosmetic surgery populations may be needed.
In closing, I would like to thank you for the opportunity to share these results with you. The Public Health Agency will be providing an information circular to practitioner organizations and the women's groups who participated in the development of the study.
I'd also like to thank the committee for its interest in the agency's ongoing risk assessment and analysis efforts for cancer and other chronic diseases.
Merci.