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Long-Term Health Outcomes in Women With Silicone Gel Breast Implants: A Systematic ReviewLong-Term Health Outcomes With Silicone Gel Breast Implants

Ethan M. Balk, MD, MPH; Amy Earley, BS; Esther A. Avendano, BA; and Gowri Raman, MD, MS
[+] Article, Author, and Disclosure Information

This article was published at www.annals.org on 10 November 2015.


From the Center for Clinical Evidence Synthesis, Institute of Clinical Research and Health Policy Study, Tufts Medical Center, and the Mapi Group, Boston, Massachusetts, and the Center for Evidence Based Medicine, Brown University School of Public Health, Providence, Rhode Island.

Disclaimer: This review was commissioned and supported by the Plastic Surgery Foundation, through financial contributions provided by Allergan Inc., Mentor Worldwide LLC, and Sientra Inc.

Acknowledgment: The authors thank the members of the Advisory Panel and staff at the American Society of Plastic Surgeons/Plastic Surgery Foundation, Arlington Heights, Illinois, for their clinical expertise and administrative support. We also thank our colleagues Daniel Driscoll, MD (plastic surgery) and Senada Arabelovic, MD (rheumatology), at Tufts Medical Center, Boston, Massachusetts, for their clinical input.

Disclosures: Dr. Balk, Ms. Earley, Ms. Avendano, and Dr. Raman report grants from The Plastic Surgery Foundation during the conduct of the study. Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M15-1169.

Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer.

Corresponding Author: Ethan M. Balk, MD, MPH, Center for Evidence-Based Medicine, Brown University School of Public Health, Box G-S121-8, Providence, RI 02912; e-mail, ethan_balk@brown.edu.

Current Author Addresses: Dr. Balk: Center for Evidence-Based Medicine, Brown University School of Public Health, Box G-S121-8, Providence, RI 02912.

Ms. Earley: Mapi USA, 180 Canal Street, Suite 503, Boston, MA 02114.

Ms. Avendano and Dr Raman: Center for Clinical Evidence Synthesis, Tufts Medical Center, Box 063, 800 Washington Street, Boston, MA 02111.

Author Contributions: Conception and design: E.M. Balk, A. Earley, G. Raman.

Analysis and interpretation of the data: E.M. Balk, A. Earley, G. Raman.

Drafting of the article: E.M. Balk, A. Earley, G. Raman.

Critical revision of the article for important intellectual content: E.M. Balk, A. Earley, G. Raman.

Final approval of the article: E.M. Balk, A. Earley, G. Raman.

Provision of study materials or patients: E.A. Avendano, G. Raman.

Statistical expertise: E.M. Balk, G. Raman.

Obtaining of funding: E.M. Balk, G. Raman.

Administrative, technical, or logistic support: A. Earley, E.A. Avendano, G. Raman.

Collection and assembly of data: E.M. Balk, A. Earley, E.A. Avendano, G. Raman.


Ann Intern Med. 2016;164(3):164-175. doi:10.7326/M15-1169
Text Size: A A A

Background: Silicone gel breast implants were removed from the U.S. market for cosmetic use in 1992 owing to safety concerns. They were reintroduced in 2006, with a call for improved surveillance of clinical outcomes.

Purpose: To systematically review the literature regarding specific long-term health outcomes in women with silicone gel breast implants, including cancer; connective tissue, rheumatologic, and autoimmune diseases; neurologic diseases; reproductive issues, including lactation; offspring issues; and mental health issues (depression and suicide).

Data Sources: MEDLINE, EMBASE, and Ovid Healthstar (inception through 30 June 2015), and the Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews (through the first quarter of 2015).

Study Selection: 4 researchers double-screened articles for longitudinal studies that compared women with and without breast implants and reported long-term health outcomes of interest.

Data Extraction: 4 researchers extracted data on participant and implant characteristics, analytic methods, and results.

Data Synthesis: 32 studies (in 58 publications) met eligibility criteria. Random-effects model meta-analyses of effect sizes were conducted when feasible. For most outcomes, there was at most only a single adequately adjusted study, which usually found no significant associations. There were possible associations with decreased risk for primary breast and endometrial cancers and increased risks for lung cancer, rheumatoid arthritis, Sjögren syndrome, and Raynaud syndrome. Evidence on breast implants and other outcomes either was limited or did not exist.

Limitation: The evidence was most frequently not specific to silicone gel implants, and studies were rarely adequately adjusted for potential confounders.

Conclusion: The evidence remains inconclusive about any association between silicone gel implants and long-term health outcomes. Better evidence is needed from existing large studies, which can be reanalyzed to clarify the strength of associations between silicone gel implants and health outcomes.

Primary Funding Source: The Plastic Surgery Foundation.

Figures

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Appendix Figure.

Summary of evidence search and selection.

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Figure 1.

Forest plot for breast cancer: direct (within-study) comparisons.

Random-effects model meta-analysis of ESs of incident breast cancer in women with breast implants compared directly with women without implants. Subgroup analyses were based on whether 100% of women in each study had silicone gel implants. See the Methods section for description of adequate and inadequate statistical adjustment. Adj = adjusted; ES = effect size; ND = no data; OR = odds ratio; Phet = chi-square P value for heterogeneity; RR = risk ratio.

* Adjusted only for age and year of implantation.

† Adjusted for age, race, time since surgery, and “predictors of cancer.”

‡ Adjusted for “extraneous variables.”

Grahic Jump Location
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Figure 2.

Forest plot of breast cancer: SIR analyses.

Random-effects model meta-analysis of SIRs of incident breast cancer in women with breast implants indirectly compared with the general population. Studies explicitly or implicitly adjusted only for demographic variables, such as age and race. No studies of women all with silicone gel breast implants reported SIR analyses. ND = no data; Phet = chi-square P value for heterogeneity; SIR = standardized incidence ratio.

* Adjusted only for age and year of implantation.

Grahic Jump Location
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Figure 3.

Forest plot of rheumatoid arthritis.

Random-effects model meta-analysis of ESs of incident rheumatoid arthritis in women with breast implants directly compared with women without implants. See the Methods section for description of adequate and inadequate statistical adjustment. Adj = adjusted; ES = effect size; HR = hazard ratio; ND = no data; OR = odds ratio; Phet = chi-square P value for heterogeneity; RR = risk ratio.

* Adjusted only for age and year of implantation.

† Adjusted for age, body mass index, tobacco use, hormone replacement therapy, and history of breast cancer.

‡ Adjusted for age, race, time since surgery, calendar year, education, and family history.

§ Adjusted only for age and time since s urgery.

Grahic Jump Location
Grahic Jump Location
Figure 4.

Forest plot of Sjögren syndrome.

Random-effects model meta-analysis of ESs of incident Sjögren syndrome in women with breast implants directly compared with women without implants. See the Methods section for description of adequate and inadequate statistical adjustment. Adj = adjusted; ES = effect size; ND = no data; OR = odds ratio; Phet = chi-square P value for heterogeneity; RR = risk ratio.

* Adjusted only for age and year of implantation.

† Adjusted for age, race, time since surgery, calendar year, education, and family history.

‡ Adjusted only for age and time since surgery.

Grahic Jump Location
Grahic Jump Location
Figure 5.

Forest plot of Raynaud syndrome.

Random-effects model meta-analysis of ESs of incident Raynaud syndrome in women with breast implants directly compared with women without implants. See the Methods section for description of adequate and inadequate statistical adjustment. Adj = adjusted; ES = effect size; ND = no data; OR = odds ratio; Phet = chi-square P value for heterogeneity; RR = risk ratio.

* Adjusted only for age and year of implantation.

† Adjusted only for age.

‡ Adjusted for age, connective tissue disease history, depression, tobacco use, alcohol use, body mass index, parity, and age at first birth.

§ Adjusted for age, race, time since surgery, calendar year, education, and family history.

Grahic Jump Location

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Comment
Posted on November 17, 2015
Tim Brown, FRCS
Plastic Surgeon
Conflict of Interest: None Declared
This recent study examines systematically the literature concerning silicone breast implant usage over the last 50 years, and the possible impact on women’s health (1). Not surprisingly, it concluded (as does almost every meta analysis in the history of medical publication), that further work needs to be undertaken; the evidence in inconclusive and that the study design is poor in many cases.
The conclusions of the review will undoubtedly be used to further the particular agendas of any interested party: the Universities to set up (well funded) implant registries; the surgeons to convince patients that implants are safe; and the “body activists” to convince women that “all is vanity” and issues with implants are an inevitable result of tinkering with nature. As a work of literature analysis, it is excellent, but as an article which enhances our knowledge and patient care, it fails dismally.
Perhaps the biggest issue is the assumption that breast implants have not changed since their conception in 1963. The article acknowledges that “the current evidence is mostly based on older generation implants inserted before the mid 1990s”. Both the elastomer shell and cohesive gel filler are radically different from these early products, and it beggars belief that the conclusions concerning the former should be used to judge the latter. Accepting this is the case, the study should exclude all studies that review usage of the now obsolete, pre 1997 liquid gel implants.
It is also worth perhaps taking a more global view, that despite half a century of using silicone breast implants in many millions of women, we still have to look very, very hard indeed to demonstrate whether any true associations exists between silicone gel implants and long term disease. Accepting that there is insufficient data concerning potential cofounders, it is entirely possible that as our environment continues to change, so will those cofounders, and as such a true answer will always be elusive. The suggested solution is the development of breast implant registries to monitor the life of an implant and the individual in which it is placed. The problem with breast implant registries that aim to act as clinical quality, rather than product registries, is that they can never predict all cofounders in a changing environment, and as such will always produce inadequate results once the data is examined many years later. Focused, hypothesis based research remains the manner in which these associations should be examined.
It needs to be openly acknowledged that since the Second World War silicones are ubiquitous within our environment. They are present in everything from foodstuffs and cosmetics, to the syringes which may be used to treat patients suffering from the diseases examined in these studies. Perhaps a more meaningful endeavour might be to examine the impact on long term health in individuals who have a known high exposure to liquid silicones, including diabetics, hairdressers, car mechanics and those working in silicone breast implant factories?

Reference
1. Nanayakkara PW, de Blok CJ. Silicone Gel Breast Implants: What We Know About Safety After All These Years. Ann Intern Med. 2015 Nov 10. doi: 10.7326/M15-242
Should Physicians Encourage Breast Augmentation?
Posted on February 16, 2016
Sonya Del Tredici, MD
General Internist, Wellspan Health, York, PA
Conflict of Interest: None Declared
TO THE EDITOR:

I read with interest Balk and colleagues’ systematic review article, The Long-Term Health Outcomes in Women with Silicon Gel Breast Implants (1), as well as the two accompanying editorials on the post-marketing surveillance efforts of these products (2-3). To my disappointment, none of the authors addressed a fundamental issue in this discussion: why are these implants so popular with American women, and what is our role as physicians in encouraging these surgeries? In the current era of high-value care, should so many medical resources be spent on breast augmentation? Should physicians support the body dysmorphia that makes women with normal and healthy bodies seek out costly, invasive, and possibly risky interventions to make themselves conform to an unnatural and unattainable ideal?

As a general internist I have many patients with breast implants, and as they get older, most wish they had never had them done. I am glad that no conclusive health risks have been identified, but there are many long-term annoyances, not quite rising to the level of “complications,” such as difficulties with breastfeeding, problematic mammograms, partial ruptures, scarring, discomfort lying on the stomach, and unnaturally youthful breasts that no longer match the normally aging body of a woman in her 50s or 60s.

Rather than hearing, “Your body is healthy and normal” from their physicians and society, women are told they are deformed and undesirable, and encouraged to get breast augmentation. As physicians we should be discouraging women from getting any kind of breast implants except in the cases of true disfigurement from mastectomy or trauma, and support women in accepting their normal healthy bodies.

Sonya Del Tredici, MD
Wellspan Health
York, Pennsylvania

References

1. Balk EM, Earley A, Avendano EA, Raman G. Long-term health outcomes in women with silicone gel breast implants. A systematic review. Ann Intern Med. 2016; 164:164-75. doi:10.7326/M15-2427

2. Nanayakkara PW, de Blok CJ. Silicone Gel Breast Implants: What We Know About Safety After All These Years. Ann Intern Med. 2015 Nov 10. doi: 10.7326/M15-242

3. Rohich RJ, Wan D. Working Toward a Solution: The Unasnwwered Questions about Silicon Gel Brest Implants. Ann Intern Med. 2016; 164:201-202. Doi 10.7326/M15-2307.
Author's Response
Posted on April 11, 2016
Ethan Balk, MD, MPH, Gowri Raman, MD, MS
Brown University, Tufts Medical Center
Conflict of Interest: None Declared
We respectfully submit that Dr. Brown is over-interpreting our review’s purpose, methodology, and conclusions. We evaluated the narrow question of whether there is sufficient comparative observational study data to support (or refute) any putative associations between silicone gel implants and long-term adverse health outcomes. Future reviews would need to assess the evidence regarding associations of environmental silicone exposure and health outcomes. Assessing the totality of evidence regarding breast implants, the answer was, in brief, no, the examined evidence is inadequate to make conclusions about silicone gel implants’ long-term safety. This conclusion in no way supports any pro- or anti-surgery, implant, or silicone agenda. Dr. Brown makes an important point that the composition and design of silicone gel implants have evolved over time. However, this concern is only one among many, including that only rare studies evaluated silicone gel implants, per se, that the types of breast implants were almost never adequately described, and, crucially, that all studies made inadequate (or no) adjustments for the fundamental differences between women who chose to have breast implants and those who chose not to. Furthermore, if we had limited the analysis to studies of new implants, and in particular only silicone gel breast implants in use today, it would have been a very brief analysis with essentially no findings. We agree that a registry would be of value for future researchers to better analyze putative harms from silicone gel breast implants. But, as Dr. Brown notes, no such registry will ever capture all potential confounders. In addition to the registry, future well-analyzed studies (or re-analyses of existing studies) will be necessary. However, it is unrealistic to expect that any future study will conclusively demonstrate any association, or lack of association, for all diseases or conditions, particularly rare ones.


Ethan M. Balk, MD MPH

Center for Evidence-Based Medicine, Brown University School of Public Health, Box G-S121-8, Providence, RI 02912.

Gowri Raman, MD, MS

Center for Clinical Evidence Synthesis, Tufts Medical Center, Box 063, 800 Washington St., Boston, MA 02111.
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