SILVER SPRING, Md. — US medical authorities are revisiting the safety of breast implants used by millions of American women, the latest review in an ongoing debate about their potential health effects.
A panel of specialists assembled by the Food and Drug Administration opened a two-day meeting Monday to discuss the latest evidence about the risks of illness and complications with the devices, which have been sold since the mid-1960s.
Breast augmentation is the most popular form of cosmetic surgery in the nation, with roughly 300,000 women undergoing the procedure each year. Another 100,000 women receive implants for breast reconstruction after cancer surgery.
The panel will hear from researchers, plastic surgeons, patients, and manufacturers and then recommend next steps. The FDA is not required to follow the group’s advice, though it often does.
For now, the FDA isn’t proposing any new restrictions or warnings. The agency’s longstanding position is that implants are essentially safe as long as women understand they have complications, including scarring, pain, swelling and implant rupture.
The FDA and other regulators around the world have been grappling with how to manage a recently confirmed link to a rare cancer and thousands of unconfirmed claims that the implants can contribute to other chronic ailments.
‘‘It is essential we try to understand breast implant illness,’’ said Stephanie Manson Brown, an executive with implant maker Allergan. But she added that there is no medically recognized definition of the problem or standardized way to diagnose it.
Most confirmed cases of the cancer, known as breast implant-associated anaplastic large cell lymphoma, have involved a particular style of implants with a textured surface, designed to reduce scar tissue and slippage.
The FDA has said it is unclear if the cancer is solely linked to textured implants or also involves smooth implants, which make up most of the US market. Lack of data on the total number of implants in use makes it almost impossible to determine how frequently the cancer occurs, the agency notes.
Thousands of women have also blamed their implants for a host of chronic ailments, including rheumatoid arthritis, chronic fatigue and muscle pain. The panel will hear from dozens of women; many of them have called on the agency to place new warnings and restrictions on the implants.
In 1992, the FDA temporarily pulled silicone gel implants from the market because of fears they might cause breast cancer, lupus and other disorders. But when studies seemed to rule out most of the disease concern, regulators returned them to the market in 2006.
But critics of that research noted its shortcomings at Monday’s meeting.
‘‘The studies at that time were not very good and did not have the statistical power to determine rare diseases,’’ said Diana Zuckerman, president of the nonprofit, National Center for Health Research, which published an analysis of more than 20 breast implant studies last year.
The FDA says on its website there is no ‘‘apparent association’’ between breast implants and chronic, debilitating diseases, however, earlier this month the FDA appeared to signal a shift in its thinking.
The agency said it would begin studying whether certain materials used in breast implants can trigger health problems in patients.