Women who get silicone breast implants are likely to need additional surgery within 10 years to address complications such as rupturing of the device, US health regulators said.
The Food and Drug Administration will work to revise safety labels for silicone breast implants after reviewing data from several long-term studies, which also showed that the products had a small link to a rare form of cancer.
The agency said the studies overall confirmed its decision that implants can be used safely, but noted the conclusions could be limited because some women dropped out.
Not lifetime devices
"The key point is that breast implants are not lifetime devices," said Jeff Shuren, director of the FDA's Centre for Devices and Radiological Health. "The longer you have the implant, the more likely you are to have complications."
There were almost 400,000 breast enlargement or reconstruction procedures in the United States in 2010, according to the American Society of Plastic Surgeons. That includes silicone and saline implants.
Up to 70% of all women who received surgery due to disease or trauma, and up to 40% of those getting an enlargement procedure using silicone, needed another operation within 10 years, post-approval studies showed.
The FDA approved silicone gel-filled breast implants sold by Allergan and Johnson & Johnson's Mentor unit in 2006. It had banned silicone implants for most US women in 1992 after some complained that the devices leaked and made them chronically ill.
As a condition of taking the devices to market, both companies were required to conduct post-approval studies of 40,000 women for 10 years, as well as extend smaller pre-approval studies. The FDA considered the companies' results, as well as reports of negative events and scientific literature.
Based on the data, the FDA said most common complications were localised, such as the hardening of the breast area around the implant, rupture or deflation of it, and the need for additional surgeries.
Other local complications include implant wrinkling, asymmetry, scarring, pain, and infection at the incision site.
The report also found a small correlation between implants and anaplastic large-cell lymphoma, a form of cancer that affects about 3,000 Americans a year.
From 1997 to 2010, there were about 60 cases of ALCL reported for women worldwide out of about 5 million to 10 million women who had breast implants, Shuren said.
"If there's a true association between that cancer and implants, it's very, very rare," he said.
The FDA said most long-term studies confirmed initial results, and that most risks of implants were well known.
"Most women reported high levels of satisfaction with their body image and the shape, feel and size of their implants," the FDA report said, adding that they should monitor their breasts for the rest of their lives.
The agency also cautioned that post-approval study data could be limited because of the low response rates.
In the large 10-year studies of 80,000 women, Allergan collected preliminary two-year data for 60% of participants, while Mentor collected three-year data for only 21%.
Diane Zuckerman, president of the advocacy group National Research Centre for Women & Families, said the high dropout rates meant the study was not accurate.
"So many of the women dropped out before the research was completed that it is impossible to say what percentage of women need additional surgery or have health problems five or 10 years after getting breast implants," she said.
"This raises questions about FDA's reliance on studies required after a product is approved," she added. - (Anna Yukhananov/Reuters, June 2011)