Metal implant, tumor

The carcinogenic feature of some metals is well known, and tumors arising at the site of metal implants have been observed in animals. Heath et al. (1971) showed that wear particles from prostheses constructed from Co-Cr alloys were carcinogenic for rat muscles, while Sinibaldi (1976) reported eight cases of bone sarcoma originating in close proximity to various metallic surgical implants used to treat common canine and feline fractures. 

The most frequently reported tumors in humans at sites of metal implants are malignant fibrous histiocytoma, fibrosarcoma, osteosarcoma and rhabdomyosarcoma, with descriptions reported of at least 20 cases for each lesion (Mathiesen et al. 1995 Laffargue etal. 2001). The same amount - 80 to 100 cases - can be esti-... 

In spite of the few cases of malignant tumors arising vith respect to the large number of metal implants used in humans, these arguments deserve serious consideration. As proposed earlier by Aspley (1989) and Jacobs et al. (1992), the establishment of an international or vorld- vide register of such cases vould facilitate future kno vledge. 

SiNiBAiDi K, Rosen H, Liu SK and Deangeiis M (1976) Tumors associated with metallic implants in animals. Clin Orthop 118 257-266. 

Well-documented cases of carcinoma and sarcoma have developed in refinery workers who inhaled nickel and chromium and in miners who were exposed to iron or even at local injection sites of iron dextran [13]. Aluminum has been linked to a high rate of lung and bladder cancer in exposed individuals and titanium has been associated with experimental induction of lymphoreticular tumors and leukemia. Although the results have not been universally accepted, many animal experiments have shown a direct correlation between the initiation of sarcomas and the injection of particulate metal debris. This appears to be related to the concentration, as well as the physical nature, of the metal implanted [14]. Metal ions, particularly cobalt, chromium, and nickel, are known to induce infidelity of DNA synthesis by causing the pairing of non-complimentary nucleotides and thereby creating a misinterpretation of the genetic code which may lead to neoplasia. 

Beryllium metal, beryllium-aluminum alloy, beryl ore, beryllium chloride, beryllium fluoride, beryllium hydroxide, beryllium sulfate, and beryllium oxide all produce lung tumors in rats exposed by inhalation or intra-tracheally. The oxide and the sulfate produce lung tumors in monkeys after intrabronchial implantation or inhalation. A number of compounds produce osteosarcomas in rabbits after their intravenous or intramedullary administration. ... 

Chromite ore roast mixed with sheep fat implanted intrapleurally in rats produced sarcomas coexisting with squamous cell carcinomas of the lungs the same material implanted in the thigh of rats produced fibrosarcomas/ However, the lARC concluded that these studies were inadequate to fully evaluate the carcinogenicity of this compound/ Other animal studies have found no increase in the incidence of tumors with chromium metal and chromite ore/ The lARC has determined that there is inadequate evidence in humans and animals for the carcinogenicity of metallic chromium and chromium(III) compounds. 

Rhabdomyosarcomas developed in rats injected intramuscularly with the powder of either pure cobalt metal or cobalt oxide. In other studies implantation of cobalt caused local fibrosarcomas in rabbits, but inhalation studies in hamsters did not reveal any increase in tumors from cobalt oxide. Lifetime exposure to cobalt sulfate by inhalation resulted in increased incidence of alveolar/bronchiolar neoplasms and a spectrum of inflammatory, flbrotic, and proliferative lesions in the respiratory tract of male and female rats and mice. ... 

There is no evidence for cancer inducement by dental alloys, but orthopedic implants and endoprostheses with evidently higher metal release may cause different types of tumors, as has been reported in several hundred cases. 

Humans concluded that there was sufficient evidence for the carcinogenicity of soluble calcium chromate and several relatively insoluble hexavalent chromium compounds in laboratory animals. Tumors were mainly induced at the administration site. In addition, experimental exposure to Be, Cd, Ni, and Sb has caused lung tumors in rats, while various beryllium compounds produced osteosarcomas in rabbits by implantation or injection (Hayes 1997). Rossman et al. (2001) could show a co-carcinogenic action of arsenic with solar UV radiation on mouse skin. Apparently strain as well as species differences of the susceptibility to the action of metals may cause variable outcome of carcinogenicity tests for example, in mice this is caused by higher metallo-thionein levels (Oberdorster et al. 1994, Waalkes and Rehm 1994). 

Silver in the metallic state is not readily eliminated from the body. Following intramuscular implantation, silver will complex with sulfur-containing amino acids or proteins and may remain permanently immobilized at the site of the implant (Luckey and Venugopal 1997). Implantation of silver foil has been demonstrated to induce fibrosarcoma in rats at the implant site, particularly when implanted subcutaneously (Oppenheimer etal. 1956). Subcutaneous injection of colloidal silver has likewise been shown to induce tumor formation. Autometallography is used to highlight... 

Injection site tumors are induced by many nickel compounds that do not cause cancer in animals by other routes of exposure. In fact, most of tihe published literature on nickel carcinogenesis concerns injected or implanted metallic nickel or nickel compounds these data are of limited value in determining carcinogenic exposure levels for avian and terrestrial wildlife. The applicability of these studies to a recommendation for human workplace exposure is also questionable. Nevertheless, injection or implantation site sarcomas have... 

The radiation source used in radiation therapy may be inside or outside the body. In almost all cases, radiation therapy uses gamma radiation emitted by radioisotopes. Any alpha or beta radiation that is emitted concurrently can be blocked by appropriate packaging. For example, is often administered as seeds consisting of a core of radioactive isotope coated with 0.1 mm of platinum metal. The platinum coating stops the alpha and beta rays, but the gamma rays penetrate it readily. The radioactive seeds can be surgically implanted in a tumor. 

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