BETHESDA BHC SPB — BETHESDA -- Adding fuel to the growing controversy over silicone breast implants, two radiologists told a federal advisory panel yesterday that the devices may rupture at 10 times the rate claimed by a manufacturer.
Although they urged women not to panic, they said many patients whose implants have ruptured and leaked silicone into surrounding tissue may be completely unaware of it. Often, they experience no pain, and cannot see or feel any evidence that the implant has changed its shape.
In many cases, they said, tests such as mammography or ultrasound may be the only way to detect a ruptured implant.
"We cannot feel many of these ruptures," said Dr. Judy M. Destouet of the Washington University School of Medicine in St. Louis. "The plastic surgeons doubt whether we are reporting actual findings. But these [leaks] indeed can be clinically silent."
Dr. Destouet told the Food and Drug Administration's advisory panel that 4.6 percent of the 350 implant patients whom she screened with X-ray mammography -- about one in 20 -- showed evidence of rupture.
Dr. Kathleen Harris of the University of Pittsburgh said she found a slightly higher rate of breakage in the more than 200 implant patients she screened. Moreover, the radiologists agreed that the rupture rates may be higher than their studies found -- perhaps twice as high -- because mammograms don't always detect breaks. Their reports compared with recent claims by Dow Corning, a leading manufacturer of the gel implants, that the devices broke in one in 200 patients.
Testimony by the radiologists came in the first day of a three-day hearing into the safety of silicone-gel implants, which have been surgically placed into 1 to 2 million women over the past three decades.
Although most implants have been used for cosmetic reasons an estimated 15 to 20 percent have been used to reconstruct breasts after cancer surgery.
The radiologists said most of the ruptures occurred in pre-1985 devices, made with thinner walls than the presumably tougher implants of today. But Dr. Destouet, who performed her study between 1986 and 1991 said she noticed some ruptures in relatively modern implants, including at least one patient whose implants were only a year old.
This is the second time in three months that the advisory panel has convened to weigh evidence about the implants' safety. The first time, in November, the experts advised Food and Drug Commissioner David Kessler to allow the devices to remain on the market pending results of further safety studies.
But on Jan. 6, Dr. Kessler called for a voluntary moratorium on their use of silicone implants because of new information suggesting that Dow Corning employees and surgeons had voiced doubts about the implants' safety for many years. New concerns also revolve around case reports involving implant patients who have developed autoimmune disorders: diseases in which the immune system attacks the body's own tissue.
There have been no large-scale studies to determine whether implant patients suffer these illnesses at a higher rate than the general population, although some critics say there is compelling evidence that silicone seeping or rupturing through the rubber-like envelope is to blame in some cases.
Yesterday, Dr. Kessler said the moratorium will remain in effect until late April, when he will finally decide whether surgeons can resume their use. In the meantime, surgeons are free to use implants filled with salt water, which are thought to be relatively safe.
In some of the most emotional testimony of the day, four physicians described scores of implant patients who had suffered autoimmune diseases such as rheumatoid arthritis, lupus, and scleroderma.