Silicone-gel implants for breast augmentation are not without problems, but Utah plastic surgeons say the cancer threat has been greatly exaggerated and is needlessly alarming millions of women who've had the operation.

Dr. Gary R. Hunter is president of the Utah State Plastic Surgery Society. Hunter, like other local plastic surgeons, has been barraged with calls since a private health advocacy group recently called for an immediate halt to the use of silicone implants for breast enlargement.In a letter to the federal Food and Drug Administration, the Public Citizen Health Research Group urged the agency to tell women who have had such a procedure they may run a heightened risk of problems, including cancer.

The FDA has already scheduled a meeting of its plastic surgery devices advisory panel to review potential health problems.

According to an FDA document, there have been reports of fibrous tissue growth around implants, which can cause a painful hardening of the breast. It is also possible that the implants could interfere with mammography pictures of the breast. Moreover, small quantities of the gel have also been shown to migrate throughout the body, and this has raised questions about possible effects on the immune system and a fetus.

A study by Dow Corning Corp., a major manufacturer of silicone-gel, showed the gel can produce tumors in laboratory rats. But company officials said patients who have had such surgery, or who are considering it, face no significant risk - based on all the data available.

Nevertheless, it's Dow's study that ignited the concern of the Public Citizen Health Research Group.

Hunter insists the study is misleading.

"Women with breast implants have been followed up for up to 25 years, and the type of cancer found in the study of rodents has never been reported in this population," he said. "As a matter of fact, current data indicates that breast cancer of any type is not any more common in augmented women than in women without implants."

Hunter said researchers have known since the early 1950s that certain types of laboratory mice and rats develop fibrosarcoma in response to almost any type of solid implant, including cellophane, metals and various plastics.

"Responsible scientists agree that the incidence of fibrosarcoma in rats injected with silicone gel has little if any relevance to humans," he said. "The Public Citizens Health Research Group's dramatic over-reaction to this very limited study can only unnecessarily alarm the estimated 2 million American women who have breast implants, as well as the many more who are contemplating the procedure."

Hunter said if silicone carried special dangers, persons with pacemakers and plastic joints, as well as insulin-dependent diabetics, would have shown a higher than normal incidence of cancers.

It's estimated that insulin-dependent diabetics, who are injected with silicone-lubricated syringes, have as much of the substance in their bodies over a lifetime as women who have breast implants.

The FDA said about 130,000 breast implants are done per year, most for cosmetic purposes.

In view of the large number of women who receive them, the FDA has invoked a procedure whereby silicone gel implants will have to undergo the type of scientific review normally associated with new medical devices.

This means that in order for the implants to remain on the market, manufacturers will have to supply the FDA with scientific data demonstrating that they are safe and effective.