The answer to the first question is that there is no evidence to link breast implants with the development of cancer in the breast. With regards to mammography, a breast implant does reduce the amount of breast tissue that is visualised on the x-ray by around 45% where the implant is in a sub-mammary pocket, and by around 25% in cases of sub-muscular or dual plane augmentation.
A recent Canadian meta-analysis (a study of published evidence) appearing in the British Medical Journal suggests that survival in women diagnosed with breast cancer following breast augmentation is slightly reduced compared with women without breast implants. However, the authors urge caution in the interpretation of their results due to the small number of studies evaluated and the non-standardised methodology employed in each one.
The lifetime breast cancer risk for women in the United States is estimated at one in eight. In women under 30 years the risk is around one in 1,900 and in those under 40 around one in 200. Patients with breast implants should be advised that there may be a risk of slightly later detection of non-localised breast cancer by routine screening, although displacement techniques at mammography and other imaging modalities, such as ultrasound and MRI, may have a role in improving early detection.
Most plastic surgeons will advise that women over 40 years considering any form of cosmetic breast surgery should undergo screening mammography in advance.
There is still, therefore, no real clarity on this issue, with articles on breast implants and breast cancer and silicone and breast cancer risk in the North American literature having shown that breast cancer is detected no later in women with implants than those without, and that outcomes are no worse.