Silicone Gel Breast Implants – Report of the Independent Review Group, 1998

In response to concerns expressed by women about a possible link between silicone gel breast implants and health problems, the British Minister of Health asked the Chief Medical Officer to conduct a review of the use of silicone gel breast implants in the United Kingdom. The Chief Medical Officer addressed this request by setting up an Independent Review Group (IRG).

The IRG was given the responsibility of reviewing the evidence relating to possible health risks associated with silicone gel breast implants. The members of the group were selected for their independent views, their knowledge and understanding of the issues, and their lack of any invested interest in the conclusions reached. The members and advisors of the group included a cell biologist, epidemiologist, histopathologist, internist, immunologist, lawyer, medical microbiologist, pathologist, plastic surgeon, rheumatologist, and toxicologist. The IRG evaluated an extensive literature, and took evidence from expert witnesses, patients, patient groups, clinicians, lawyers, manufacturers, and scientists. They gathered evidence from experts in the United Kingdom and overseas.

By the time this report was published in 1998, the IRG had evaluated both the existing and emerging scientific evidence for a link between silicone gel breast implants and adverse effects on health. In addition, they gathered evidence on the quality and quantity of information routinely provided to women considering breast augmentation.

The IRG:

–       Reviewed the existing medical reports and evidence

–       Identified and considered new evidence

–       Considered the possible existence of a new, undefined syndrome

–       Considered the range of risks associated with silicone gel breast implants

–      Examined whether patient information is satisfactory

–       Considered how good clinical practice can be assured


The IRG considered evidence from a number of sources:

–    Oral evidence from representatives of patient groups, lawyers, researchers, physicians, plastic surgeons, manufacturers, and the National Breast Implant Registry.

–   Written evidence from women with breast implants, replies to requests for information, and additional information from those who gave oral evidence.

–   Plaintiff and defense submissions to the scientific panel appointed to review the scientific merits of evidence presented in litigation in the United States

–   Unpublished scientific information, legal submissions, letters from women with silicone gel breast implants, internet and press articles

–   Scientific publications

–   Data provided by implant manufacturers.


The IRG reached a number of important conclusions:

1. There is no histopathological or conclusive immunological evidence for an abnormal immune response to silicone from breast implants in tissue.

2. There is no epidemiological evidence for any link between silicone gel breast implants and any established connective tissue disease. If there is a risk of connective tissue disease, it is too small to be quantified. The IRG cannot justify recommending further epidemiological studies to investigate this hypothesis.

3. Good evidence for the existence of atypical connective tissue disease or undefined conditions such as ‘silicone poisoning’ is lacking. It is possible that other conditions such as low-grade chronic infection may account for some of the non-specific illnesses noted in some women with silicone gel breast implants.

4. The overall biological response to silicone is consistent with conventional forms of response to foreign materials, rather than an unusual toxic reaction.

5. There is no evidence that children of women with breast implants are at increased risk of connective tissue disease.

6. The IRG recognized that there were issues such as the precise incidence of rupture where the scientific data were incomplete so that rigorous conclusions could not be drawn.


The IRG noted several additional observations:

–   There are physical and psychological benefits of breast implantation for many women.

–   There are a number of complications such as capsular contracture and gel bleed associated with breast implantation.

–   Information provided to women to assist them in making informed decisions about whether to proceed with breast implant surgery is frequently inadequate, in terms of broke both quality and quantity.

–   There is a need to extend the principles of good clinical practice and clinical audit across some areas of the private sector

–   There is a need to improve scientific quality in a number of areas of research relating to aspects of silicone gel breast implants.


To address these areas of concern, the IRG made several recommendations.


more to come