Particle contamination on the surface of breast implants made by Brazilian devicemaker Silimed poses, at worst, a "one in a million" risk to patients, according to a report released on Monday by the Dutch National Institute for Public Health and the Environment (RIVM).
Last fall, EU regulators suspended all CE certificates for Silimed devices after German notified body TÜV SÜD found man-made fibers on the surface of the company's implants.
After the inspection, Sientra, the largest US distributor of Silimed implants, briefly halted sales of Silimed devices, but resumed sales in January after a third-party review found the devices to be safe.
For its part, the US Food and Drug Administration (FDA) said it was taking a "cautionary approach" to monitoring the Silimed devices, but did not issue any safety alerts or recalls for the implants.
Now, in a report commissioned by regulators in the UK, Ireland, Belgium and the Netherlands, RIVM says the risk to patients from the presence of the fibers is minimal.
"The worst case scenario shows a chance of 1 in a million that adverse health effects may occur," writes RIVM.
In light of the findings, Medicines and Healthcare products Regulatory Agency (MHRA) Director of Devices John Wilkinson says his agency is "currently liaising with the European Independent Clinical Expert Advisory Group about the safety of these products and will carefully evaluate their advice before we reach a finalised position."
However, Wilkinson says, "There is no suggestion in the RIVM report that women who have Silimed breast implants should seek to have them explanted or that any additional clinical follow-up is required."
While the study did find fibers, now believed to be man-made mineral fibers such as glasswool and rockwool, consistent with those reported by TÜV SÜD on samples of the devices manufactured between 2009 and 2015, "It is safe to conclude that the fibre dose stemming from the breast implants is far below the limit that is considered acceptable for daily, lifelong occupational exposure. Thus, the likelihood that appreciable inflammation reactions will occur is very low," the report says.
Similarly, the report concludes that the risk of patients developing cancer as a result of exposure to the fibers is within the acceptable range, even for a worst case scenario.
RIVM also acknowledges that there are "a number of uncertainties" in its analyses, owing to the fact that the toxicity studies used as reference relate to inhalation exposure to smaller sized fibers. However, despite these uncertainties, RIVM says it expects the actual risks from the fibers to be lower than the risks calculated in the report.