Silicone implants have certainly been popular and over the course of time somewhat controversial. There have been reports that breast cancer rates in women WITH silicone implants is LESS.
I recently came across a synopsis of an article that appeared in The Journal of Environmental International. The study was done by scientists at Oregon State University. They studied removed silicone implants from patients bodies and found they contained in 5 out of 8 implants P.P. DDE a carcinogenic by product from the banned insecticide DDT. They then placed silicone discs in some mice and found some sequestration of toxins in that silicone. Perhaps this is why in part women with silicone implants have a lower incidence of breast cancer. The researchers have suggested perhaps doing more toxicology studies.