Breast implants and cancer.

BACKGROUND

Although silicone breast implants have been linked to various short-term complications, less is known about their long-range effects. Most attention has focused on connective tissue disorders, but the range of immunologic disturbances observed in women with implants suggests that consideration also be given to other chronic diseases, including cancer. The greatest attention has focused on breast cancer, given clinical reports suggesting an association and observations that mammographic visualization is deterred by implants. Findings from epidemiologic studies, however, actually suggest that breast cancer risk might be reduced among women with implants, although the biologic mechanism remains undefined. In addition, most studies do not suggest that women with breast implants have more advanced breast cancer at diagnosis or a worse prognosis than those without implants. The majority of studies have focused on women who received implants for cosmetic reasons, with little previous investigation of women who received implants for breast reconstruction following cancer surgery. In terms of other cancers, animal as well as clinical data suggest potential risks of sarcomas and hematologic cancers, including multiple myeloma. The risk of these cancers has not yet been adequately addressed by epidemiologic studies, although several ongoing studies should provide insights. It will be important for studies to consider effects of other lifestyle factors as well as to analyze relationships according to duration of implantation, a demonstrated determinant of implant deterioration. In addition, consideration should be given to type of implant, including implants with polyurethane foam covers, which can leak toluene diamine, a demonstrated carcinogen in animals.