Purpose: Surgery is generally proposed for the treatment of giant-cell bone tumours but other options are discussed. The problem is to decide between curettagefilling and enucleation, using or not local adjuvant treatment with curettage, and filling with an autograft, an allograft, or cement. The purpose of this work was to provide a new perspective to the treatment of giant-cell tumours based on the tumour pathophysiology and calcitonin infiltration.

Material and methods: We report 25 cases of benign giant-cell tumours treated by calcitonin. Mean patient age was 31 years. Female gender clearly predominated (75%). All of the tumours were located at the extremity of long bones. We grouped the tumours as quiescent benign tumours, and active or aggressive tumours according to the Enneking classification. Our treatment protocol included four stages after histological confirmation of the diagnosis on the biopsy specimen. The first stage was aggressive curettage, followed by intramuscular injection of calcitonin until cutaneous healing. The third stage involved daily washing of the tumour cavity with saline solution for one month. The final stage lasted two months with intramuscular injections of calcitonin.

Results: We analysed outcome at mean three years (range 2 – 20 years). Progressive filling of the tumour cavity was observed in the majority of patients starting with the first month of treatment even for the aggressive forms where tumour resection was tempting. Using the Enneking scale, our rates were near 90%, largely above the rates obtained with other conventional techniques. There were no complications. We did however have eight cases of recurrence including three which were treated again with the same protocol with good outcome.

Discussion and conclusion: Giant-cell bone tumours are clearly hormone sensitive. Calcitonin would appear to arrest the osteolytic process by attacking the osteoclast-like cell which bears calcitonin-receptors. Daily washing of the tumour cavity is designed to modify the microenvironment and eliminate tumour growth factors and cytokines expressed by giant-cells. More detailed studies of the cell membrane might reveal an explanation of certain calcitonin escape phenomena which are the cause of more or less long-term recurrence.