A new study has found that metal-on-metal hip implants are not associated with an increased risk of cancer in the early years following implantation. However, even the study’s authors acknowledge that its findings are limited, and that much more extensive research will be needed before it can be confidentially stated that metal-on-metal hip replacement devices don’t raise cancer risks.
Metal-on-metal hip replacement have come under scrutiny in recent years, following the high-profile recall of DePuy Orthopaedics’ ASR hip implant devices, which were failing prematurely in an unexpectedly high number of people. Since then, a number of studies have found evidence that that the devices can shed dangerous amounts of chromium and cobalt into patients’ bloodstream, leading to early implant failure, adverse local tissue reactions, bone and tissue loss, the development of pseudotumors and other long-term health problems.
Earlier this summer, the U.S. Food & Drug Administration’s Orthopaedic and Rehabilitation Devices Panel recommended that new warnings be included on the labels for such devices, and that metal-on-metal hip implant patients undergo regular monitoring to ensure their devices are not failing.
Some research has raised concerns that exposure to the dangerous amounts of metal ions shed by all-metal hip implant devices could cause genetic changes at the cellular level that are associated with the development of cancer. But according to a report from MassDevice.com, a study published in the British Medical Journal in April and presented last week at a meeting of the British Orthopaedic Association found “no association between metal-on-metal hip replacements and increased incidence of cancer in the first seven years after hip replacement.” The study was performed by the UK National Joint Registry (NJR) and based on UK National Health Service Hospital Statistics.
According to a report from Reuters, however, the researchers were unable to reach any conclusion regarding the risk of cancer associated with metal-on-metal hip replacement over the long-term. The NJR said that metal-on-metal hip implants should continue to be tracked, as many cancers can take longer to develop.
“We must, however, point out that many cancers have prolonged latency after initial exposure to carcinogens and thus long-term follow up is needed to provide a definitive answer,” the NJR said in its Annual Report.