Study: Metal hips don't heighten cancer risks

For all the bad press metal-on-metal hips generate these days over potential malfunctioning and other safety concerns, a new study offers a small piece of good news for the products: The implants don't appear to boost cancer risks after their first 7 years of use.

The British Medical Journal published the details, and a Bloomberg story offers a good summary of the findings, which scientists compiled using computer models. 

Researchers evaluated data from the U.K.'s National Health Service and the National Joint Registry of England and Wales involving 40,576 patients with metal-on-metal hip implants. They also gathered data from 248,995 patients with alternative bearings. What they looked for, according to the story: incidences of cancer based on hospital admissions.

What they found: Patients with the metal hip implants have about the same risk of developing cancer as does the general population or patients with non-metal implants. This included cancers such as malignant melanoma prostate and blood cancers, which as Bloomberg notes can be connected to metal ions inside the body.

Still, metal-on-metal implants aren't in the clear yet as far as cancer. The researchers, from the University of Bristol in the U.K. and elsewhere, cautioned that a longer-term study is necessary because certain tumors take a longer time to develop. Such a review would focus on what happens to the body when implants leak metal particles, the story notes.

The research is a small glimmer of good news for manufacturers of metal hips even as the bad news mushrooms. Earlier this week, U.K. regulators urged surgeons to stop using metal-on-metal hip implants made by Johnson & Johnson ($JNJ) and Stryker ($SYK) because of their implants' higher rate of repair or replacement needs, compared with competing ceramic or plastic joint implants. In the U.S., Consumer Reports recently blasted the safety of hip and other joint implants, and the FDA is seeking studies of artificial hips from every approved manufacturer.

- read more in the Bloomberg story
- check out the journal abstract