Can breast reconstruction with gel-filled silicone implants increase the risk of death and second primary cancer in patients treated by mastectomy for breast cancer?

An increased risk of cancer and autoimmune disease associated with gel-filled silicone implants has been suggested recently, but these possible detrimental effects have not been adequately studied in patients with breast cancer. In order to evaluate these effects, we have studied 146 patients with breast cancer treated by mastectomy at the Gustave Roussy Cancer Institute between 1965 and 1983 and who received a gel-filled silicone implant for immediate or delayed breast reconstruction between 1976 and 1984. These patients were compared with 146 matched controls with breast cancer who were treated in the same center by mastectomy without breast reconstruction and were matched for age at diagnosis (within 10 years), year of diagnosis (within 3 years), stage, histologic type of the tumor, histopathologic grade, and nodal status. The relative risks of death, relapse, and second primary cancer were estimated by means of the Cox proportional hazards model stratified on age at diagnosis. The risks of distant metastasis and death due to breast cancer were significantly lower in the breast reconstruction group than in the control group. The risks of local recurrence, second breast cancer, and second primary cancer in another site than the breast were not significantly different between the two groups of patients. Our results do not support the hypothesis of a detrimental effect of gel-filled silicone implants either in the course of breast cancer or in the risk of death due to other diseases.