A 10-Year Experience of Routine MRI Screening for Silicone Implant Rupture: Are FDA Recommendations Supported by Evidence?
Theresa Y. Wang, M.D., Claudia Albornoz, MD, Qunying Hu, MD, Elizabeth Morris, MD, Peter C. Cordeiro, MD.
Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Purpose: The U.S. Food and Drug Administration recommends routine magnetic resonance imaging (MRI) for detection of silicone breast implant rupture. Current guidelines propose patients undergo screening at 3 years after implantation and every 2 years thereafter. While most would agree with the detection and treatment of symptomatic patients and ruptured implants, there is ongoing debate on whether there is evidence to support screening of asymptomatic patients. The goal of this study was to review the results of serial silicone implant MRI screening according to current guidelines to determine the validity of FDA recommendations.
Methods: All patients who underwent breast reconstruction with silicone implants by the senior author at Memorial Sloan-Kettering Cancer Center from 1999-2009 were reviewed. FDA guidelines and MRI screening timeline recommendations were followed. Patients’ medical records were retrospectively reviewed for MRIs performed, imaging findings, follow up surgical data and evidence of rupture at explantation. Sensitivity, positive predicted value and false positive rates were evaluated. Kaplan-Meier analysis was performed to detect time to event (rupture).
Results: A total of 963 screening MRIs were performed in 383 patients with 631implants. Reconstructions were bilateral in 248 patients and unilateral in 135 patients. Mean follow up was 53.2 months. The rupture rate based on MRI results was 1.9% (12/631 implants). Explantation of implants diagnosed as ruptured in the MRI demonstrated 10 intracapsular ruptures, 1 extracapsular and 1 intact implant. Sensitivity and positive predictive value were 91.6% for MRI imaging, and false positive rate was 8.4%. Kaplan-Meier analysis showed a predicted long-term silicone rupture rate of 0.0% at 3 and 5 years, 2.3% at 7 years and 15.1% at 10 years (Figure 1). The total financial cost of the 963 MRI scans alone was 1.5 million dollars. Forty-nine patients (11% of the group) had additional incidental findings in the MRI reports, and over 30% of them underwent further tests and procedures.
Conclusions: Results of this study are in agreement with others demonstrating a low prevalence of silicone implant rupture, especially in the first 5-6 years after implantation. Predicted silicone implant rupture rates are 0% at 3 and 5 years. The net harm of incidental findings, further tests and procedures, patient inconvenience and anxiety, outweighs the benefits of early routine screening. Additional considerations are the financial cost of the scans. Based on these findings, the FDA recommendation of MRI screening in asymptomatic patients seems unnecessary until the 7th year after implantation.
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