Our review reveals several new insights about the current literature using MRIs or ultrasounds to detect silicone gel implant ruptures. Although the pooled summary measures across the studies indicate relatively high accuracy of MRI in detecting breast implant rupture with a pooled sensitivity of 87% and a specificity of 89.9%, the majority of the current literature examined only symptomatic patients. This leads to a higher prevalence of silicone breast implant rupture and higher diagnostic accuracy estimates. We found the DOR, a measure of overall diagnostic test performance, of MRI to be 14-fold greater in symptomatic samples than in asymptomatic samples and 2-fold greater in symptomatic samples than in screening samples. This was shown in the subgroup analyses with higher sensitivity and specificity of the MRI in studies examining symptomatic samples than in studies using asymptomatic and screening samples (). These findings have widespread health policy implications given the F.D.A. recommendations to repeatedly screen silicone breast implant recipients with serial MRI exams.
Instituting a screening program requires careful consideration of several issues. First, the disease should have serious consequences.50
Currently, the morbidity associated with silicone breast implant rupture remains unclear and is still under study. Second, the disease must have a pre-clinical yet detectable stage.50
For silicone breast implant ruptures, this stage may be considered gel bleeds. Our results show a lack of consistency in addressing gel bleeds (). Third, a high prevalence of the pre-clinical stage among the screening population is optimal for a successful screening program. To date, there is a lack of evidence about the prevalence of subclinical gel bleeds. In addition, many studies report the mean age of implant at time of rupture to be greater than 10 years,29–31, 34–36, 47
suggesting that perhaps this group may consist of the high-risk sample that should garner directed attention. In light of this and the possibility of very low prevalence, adherence to the F.D.A. recommendation to screen with MRI at least 4 times within the first 10 years of silicone breast implantation will be costly and may potentially result in over-detection and over-treatment of a questionable non-life-threatening condition.
In addition, important screening test characteristics to consider include the sensitivity and specificity of the screening modality. Our results reveal many methodological flaws in the current literature, which may result in higher MRI sensitivity and specificity estimates (). We showed that most of the included MRI studies reported diagnostic accuracy measures on symptomatic samples, which had a DOR that was nearly 14-fold and 2-fold greater than the DOR of detecting silicone breast implant ruptures in asymptomatic samples and screening samples, respectively. Thus, although MRI’s diagnostic performance in detecting silicone breast implant ruptures in a symptomatic sample may be quite good, we find that the MRI’s accuracy is magnitudes lower in detecting rupture in asymptomatic and screening samples.
These compelling results are noteworthy given the frequency of the F.D.A. recommendations for serial MRI exams as a screening test to detect silicone breast implant ruptures. As a screening program, these recommendations have been received with wide-spread controversy. There is a lack of high level evidence establishing serious health consequences from a ruptured silicone breast implant, and yet adherence to these recommendations result in substantial cost and use of resources. In particular, the benefits of screening within the first 10 years are unclear, and the effectiveness of such a screening program warrants further investigation. Moreover, screening programs should take into account patient preferences.51
Patient acceptability influences adherence to recommendations and have been important topics for other screening programs such as colorectal cancer52, 53
and prostate cancer screening.54
The main strength of this review is our rigorous compliance with the recommended methods for carrying out and reporting a systematic review, specifically for diagnostic accuracy studies. Systematic reviews of diagnostic accuracy studies differ from intervention studies in 3 ways: the inclusion of diagnostic accuracy search terms,19
assessment of study quality and completeness of reporting,20
and meta-analysis methods. Additionally, we attempted to identify sources of heterogeneity across these studies.55
There are several limitations to our study. First, the small number of studies may explain the lack of statistical significance of our results. The wide confidence intervals of the RDORs indicate low statistical power. Eight studies were excluded because they lacked sufficient data to construct 2×2 tables, which are essential in obtaining data to conduct meta-analyses. Efforts to contact authors were largely unsuccessful. This limitation emphasizes the importance of reporting diagnostic accuracy studies using the STARD checklist.24
Another limitation is the possibility of publication bias among MRI studies, despite an extensive search through 4 databases without any language restrictions. A possible explanation for the asymmetric funnel plot may be the small number of available included studies.56