Localized hyperthermic treatment of experimental bone tumors with ferromagnetic ceramics.

Localized hyperthermic treatment was carried out with use of a metastatic bone tumor model in rabbits. The experimental bone tumor was created by transplantation of pieces of tumor line VX2 into the medullary canal of rabbit tibiae. Two weeks after the transplantation, a ferromagnetic ceramic pin was inserted in the medullary canal. Then, hyperthermia (HT) of the tumor was accomplished with use of an alternating magnetic field for 50 min. All the rabbits were killed 5 weeks after tumor transplantation, and the therapeutic effect was evaluated histologically and roentgenographically. Almost all the tumor cells within the bone marrow were killed by this procedure. The area of tumor necrosis in the HT group was significantly larger than in the control group. The pathological fracture rate and displacement rate were reduced significantly by this treatment (38.5 and 0%) compared with the controls (92.3 and 92.3%). Therefore, HT with the use of ferromagnetic ceramics was effective for local control of malignant bone tumors and seems to be a promising new method of treatment.