Testimony on Silicone Gel Breast Implants

April 12, 2005

Sidney M. Wolfe, M.D.
Director, Public Citizen’s Health Research Group
FDA Hearing on Silicone Gel Breast Implants

Despite an extra year of data on silicone gel breast implants since the last advisory committee hearing on this topic in October 2003, the FDA approval standard for medical devices – “reasonable assurance of safety” – clearly has not been met for these devices.

Whereas at the last hearing we advocated waiting at least five more years to collect more information on the thousands of women who already have had these implants, rather than precipitously approving these unsafe devices for marketing, there are several new lines of evidence that argue strongly for ending the quest for approval of the current generation of intrinsically flawed silicone gel implants before any more women are injured.

1. New Data on Commonly Occurring Silicone Gel Migration to Lymph Nodes

In a paper just published this week in the American Journal of Surgical Pathology by researchers from the Armed Forces Institute of Pathology and Case Western Reserve School of Medicine, lymph nodes from 96 women who had had silicone gel breast implants removed (and in whom there were concerns about silicone in lymph nodes) were examined in several ways for the presence of silicone and for abnormal lymph node tissue (silicone lymphadenopathy-pathologic changes in lymph nodes involving silicone). Although there was evidence of implant rupture in only 47 (49%) of these women, lymph nodes from 86 women (90%) contained droplets consistent with silicone. A control group consisted of 12 women with breast surgery mainly associated with breast cancer but without silicone gel implants. None of the lymph nodes from these 12 women contained silicone droplets. Similarly, microscopic examination of the lymph nodes revealed abnormal cells, “foamy macrophages,” occurring much more frequently in women with silicone gel breast implants than in the control group. In the lymph nodes of 91 of the 96 women (95%) with implants, there were these abnormal “foamy macrophages” sometimes replacing normal lymph node tissue, but in the non-implant women, only 4 of the 12 (33%) had these cells, and they were described as “rare.” 

The authors commented about the clinical significance of silicone lymphadenopathy:

In a patient who has post-mastectomy reconstructive surgery using silicone gel breast implants, the clinical differential diagnosis of regional lymph node enlargement should include silicone lymphadenopathy as well as metastatic breast cancer. In most individuals with silicone gel breast implants, who have had surgery for breast augmentation, one must also consider the potential for adverse health consequences of silicone migration to regional lymph nodes. … The possibility that silicone frequently migrates to regional lymph nodes of patients with patients with silicone gel breast implants must be considered in assessing the safety of these medical devices …This phenomenon [silicone lymphadenopathy] does provide a rational basis for suggesting that silicone gel implants may have an impact on the immune system. … Finally, the role of silicone in the development of lymphoma at least deserves mention since there are several case reports describing primary breast lymphoma in patients with silicone gel breast implants as well as patients with co-existent silicone lymphadenopathy and lymphoma in the same lymph node.[1]

In FDA comments on Inamed’s proposed patient brochure for silicone gel implants, the agency is clearly dissatisfied with the company’s minimizing of risk for gel migration:

FDA believes that the patient brochure does not adequately describe the reported consequences of ruptured implants, as detailed in the package insert. FDA believes that unless surveillance is actively performed for migrated gel (i.e. either with MRI, mass spectroscopy, or biopsy), it is incorrect to assume that this is a rare occurrence.

2. New FDA Extrapolations of Rupture Data from the Core Study

Table 10: Probability of Implant rupture thru 10 years for MRI cohort (silent and symptomatic) for 3 models (from pg 39, FDA Review of Inamed Data)


Constant Hazard

Linearly increasing

Quadratically increasing













Indications combined




These long-term projections provide enough evidence to stop any further consideration of possible approval for these implants.

3. Likelihood of Lower Rupture Rates with “Gummy Bear” (cohesive gel) Implants

Although new, two-year-only data for cohesive gel implants have been submitted to the FDA by Inamed, the agency has asked for more data, presumably including for longer duration of implantation and the approval of these devices, known as model 410. These devices are therefore not being considered at this meeting. The following is derived from data sent by Inamed to the FDA and information about these “gummy bear” implants available on the Internet.

Inamed Brochure on Model 410: 

“[Y]ou want the best, the safest, the most predictable results … With style 410 … you can achieve those aims.”

Overview (from Web site Breast Implants 411) 

These [cohesive gel] implants were originally invented with two purposes in mind: 1/ to make a longer-lasting implant and 2/ to make an implant that would maintain a more attractive an predictable shape … by making the gel more cohesive, so that it is less liquid-like and more solid than other silicone gel implants. For this reason they have been known as the “gummy bear implants” … If a cohesive implant is cut in half, there is no gross movement of gel. … What happens if a cohesive gel implant ruptures?    At the time of this writing there is a report of a single rupture in a series of several thousand in Sweden. If it [a rupture] did happen … the gel, being relatively stiff and solid, would not migrate in any significant amount. … Since it has the consistency of a gummy bear, the gel would presumably stay in place … Microscopic migration of gel would probably occur … This is the subject of an ongoing investigation. (emphasis supplied)” [2]

Data Submitted by Inamed to FDA on Cohesive Gel model 410.

From table 149, page 000591 of data submitted to the FDA, the two-year risk of first occurrence of overall rupture (symptomatic and asymptomatic detected with MRI) with model 410 cohesive gel implant was 1 out of 418 patients, or 0.2% (by implant, it was 1 out of 831 implants or 0.1 %) in women getting the implants for augmentation. There were no ruptures in women getting these implants for reconstruction (table 149, page 001059), thus the total rupture rate is even less than 0.1%. This is a much lower rate than found in the data from the Core Study of silicone gel implants being presented at this meeting. These data are shown in the table below.

Rupture Rate and Rate over Time (from pg 19, FDA review of Inamed data, based on 3+ years of data


MRI Cohort (n = 663 implants)

Non-MRI Cohort (n = 1119 implants)


























Total Rate





Although these data are from 3+ years, the total rate of rupture, symptomatic and asymptomatic, in the MRI cohort is 4.8%, almost 50 times higher than the two-year rate for the cohesive model 410.

In summary, we strongly urge the panel to reject the approval of the inherently flawed Inamed and Mentor silicone gel breast implants being considered at this hearing. In addition, much more data are needed, for longer periods of time, on the cohesive gel implants. Although the rupture rates at two years are much lower, there is the concern expressed above, that “Microscopic migration of gel would probably occur …. This is the subject of an ongoing investigation.” Just as the FDA has required longer-term data on the implants being discussed at these hearings, at least five more years of data on the cohesive implants will be needed to answer questions about their safety.

[1] Katzin WE, Centeno JA, Feng LJ, Kiley M, Mullick FG. Pathology of Lymph Nodes From Patients With Breast Implants: A Histologic and Spectroscopic Evaluation. Am J Surg Pathol. 2005 Apr;29(4):506-511.