Silicone Breast Implants ; Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

The gel-filled implants came under scrutiny as part of an agency review of medical devices in use before 1976, when Congress authorized FDA to regulate devices. In particular, interest in the implants was spurred by reports of adverse effects, including:

Capsular contracture (shrinking of scar tissue around the implant that can cause painful hardening of the breasts)

Claims that the implants could hide some of the breast tissue, interfering with the ability to take and interpret quality mammograms

Questions about possible effects on the immune system due to migration of small quantities of silicone gel throughout the body

Concerns about cancer risk, especially in connection with polyurethane-coated implants (see accompanying article, "If You Have Implants").

The process for reviewing breast implants was set in motion in June 1988, when FDA designated them class III medical devices. This classification gave the agency authority to ask for safety and effectiveness data after 30 months. On April 10, 1991, the agency notified manufacturers that they must submit the information by July 9 or their products would be taken off the market.

FDA's General and Plastic Surgery Devices Panel, an outside advisory panel of medical and other experts, met last November to review the data submitted. It found the information inadequate to establish safety and recommended that FDA require the manufacturers to collect additional data on risks and benefits by a strict deadline to be set by the agency.

Nonetheless, citing a compelling public health need, particularly for reconstruction patients, the panel also recommended that implants remain available during the interim under certain conditions. These included requiring physicians to inform and educate prospective patients about potential risks and establishing a national registry to provide data on adverse effects.

On Jan. 6, FDA Commissioner Kessler called for a voluntary moratorium on the sale and use of all silicone gel-filled breast implants, pending review by the panel of new data not available to it at the November meeting.

FDA had obtained information that heightened the agency's concerns about how long the implants last in the body, how often they leak or rupture, and the possible harmful effects of silicone escaping into the body from gel bleed (leakage through the implant covering) or implant rupture. It appeared that the rate of rupture and the number of undiagnosed ruptures might be higher than earlier thought. Of particular concern was a possible connection between leaked silicone and connective tissue or immune-related disorders such as scleroderma, rheumatoid arthritis, and lupus.

At FDA's request, the advisory panel met again in mid-February to reconsider its previous recommendation in light of the new information, and to advise FDA on what counsel to give women who already have implants.

After three days of intensive hearings, the panel concluded that: - the percentage of implants that rupture is not known, that rupture may go undetected in some women, and that the rupture rate may be higher than previously thought implants should not be expected to last a lifetime

all implants "bleed" silicone gel through their outer envelope, and some percentage rupture, but that the health effects of the escaped gel are uncertain

there is not enough evidence to establish whether gel-filled breast implants can cause immune-related or connective tissue disorders — that is, whether women with the implants have a higher than normal incidence of these diseases, or whether certain groups of women may be particularly sensitive to these effects.

In addition, questions remained on what percentage of women experience capsular contracture, formation of calcium deposits in surrounding breast tissue, and changes in breast and nipple sensation.

Based on the findings, the panel called for tighter restrictions on the use of silicone gel implants.

In its April decision, the agency adopted the panel's recommendations. The core studies, expected to be completed in about three to five years, will focus on frequency of implant rupture and leakage, calcium deposits, frequency and severity of capsular contracture, extent of interference with mammography, and frequency of changes in breast or nipple sensation.

Questions about possible long-term effects such as immune-related disorders and cancer are under way at the University of Michigan and New York University. The National Cancer Institute will also sponsor a study on cancer risk slated to begin this year.

Other kinds of safety questions will be answered by laboratory studies conducted by the manufacturers under an FDA-imposed timetable. These pertain to the chemical composition and toxicity of the silicone material that "bleeds" out of the implant shell, the strength of the implant shell and its resistance to rupture, and the physical and chemical changes that the implants may undergo in the body.

If these studies establish safety and effectiveness, manufacturers will be able to reapply for marketing approval.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.