On Nov. 3, 2016 The U.S. Department of Health and Human Services (HHS) released the 14th Report on Carcinogens (RoC) that includes cobalt and cobalt compounds on its list of cancer-causing substances.
The RoC is a public health document that is science-based and congressionally mandated, describing 248 listings of agents, substances, mixtures, and exposure circumstances that are known and confirmed carcinogens. The report advises that “intracellular release of cobalt ions from particles” is a key event related to toxicity and carcinogenicity, as seen the cases of metal-on-metal hip implant failure.
Metal-on-metal hip implants are made primarily of cobalt and chromium alloy. Patients who have received this type of implant complain of loosening, bone erosion, damage to surrounding tissue, and metallosis, a dangerous blood condition that occurs when metal ions flake off the device and pollute the bloodstream.
The symptoms have been crippling for thousands of patients who have experienced significant pain and suffering they allege results from the failed device. These complaints have resulted in lawsuits against medical device manufacturers such as DePuy, Wright Medical and Stryker.
A recent study shows that the metal ions may be absorbed into the bone marrow, impairing the function of bone-forming cells. In another study, a 10- to 20-fold increase in cobalt and chromium levels were found in patients with metal-on-metal implants, many of whom have suffered from cobalt poisoning. Those symptoms include blindness, deafness, numbness of the hands and feet, and weakness that have forced them to be wheelchair bound.
The RoC report reads, “In biomonitoring studies that measured cobalt in the urine of people exposed to cobalt from various sources, the highest levels generally were due to occupational exposures and failed hip implants.”
According to the report, the normal range of cobalt occurring in a person’s system due to normal environmental exposure is 0.01 to 4.2 µg/L. The cobalt levels in a person’s system with a metal-on-metal hip implant, however, is much higher, at approximately 0.7 to 12 µg/L.