Silicone is used in thousands of ways and we all have some of it in our bodies. It's used as a lubricant in water pipes, in copy machines, hairspray, perfumes, hospital needles and syringes, pacemakers, joint implants, and many medications. Cow's milk has more silicone in it than the mother's milk of a woman with breast silicone gel implants.
In none of these silicone uses has any health problem been found.
Diagnosing cancer in the presence of implants - no study has found any delay in cancer diagnosis because of the presence of breast implants. Implants hide anywhere between 20% to 60% of breast tissue during a mammogram, especially if they're placed above the muscle, and mammograms must be done a little differently. However, in comparing groups of women with and without implants, no significant difference was found as to the size or stage of the tumor when it was diagnosed.
Family history of breast cancer - About one in nine women develop breast cancer, and if there's a family history of it, the chances of it recurring are much higher. As a precaution, all cosmetic surgeons will do a good breast exam before any augmentation procedure, and some will have such patients get a mammogram before their augmentation.