For those of you contemplating breast implants, and for those of you who have already had them, the best available data on breast cancer risk have been published. A Canadian study, published in Cancer Epidemiology (see here for abstract; email Dr. Stark if you want the entire article; he can’t post it here for copyright reasons) gives us the best data to date. The Canadians compared about 400 women with breast cancer and implants to 400 women with breast cancer without implants. There was a large excess of Stage III cancers found in the implant group, implying that the implant obscured the ability of the clinician and/or mammographer to detect cancer early. Although the differences in outcome (death rates) were not statistically significantly different in the two groups, Dr. Stark believes that this is a reflection of sample size rather than the absence of a biologic effect: there weren’t enough women studied to get to p < 0.05. If you look at the study it is clear however that at least in Canada implants delay breast cancer diagnosis. Why Canada? The Canadian health system is cost effective but referrals to specialists are not as common as in the US. Not stated in the article was whether radiologists in Canada are allowed to specialize in mammography. If not one might imagine a scenario in which early breast cancer detection in the US was simply better than in Canada. In the absence of data contained herein purporting to show any of this inherent bias, however, one is forced to conclude that patients with breast implants represent a special, and growing, subset of otherwise healthy women, for whom breast cancer screening must be approached somewhat differently.