Radiation therapy in the treatment of giant cell tumor of bone.

PURPOSE: To assess the local control rate and potential complications of radiotherapy, and the factors influencing response to radiotherapy for primary and locally recurrent giant cell tumor of bone.

METHODS AND MATERIALS: Twenty patients were irradiated for giant cell tumor of bone between 1983 and 1993. Fourteen patients received radiotherapy at the time of primary diagnosis (10 had biopsy and 4 partial surgery) and 6 patients at the time of local recurrence (following additional surgery in 2). Fourteen patients had tumors of the extremity and six of the vertebral column. The radiotherapy dose ranged from 40-60 Gy in 15-30 fractions over 3-6 weeks. The response to radiotherapy was assessed by clinical and radiological criteria and the probable factors influencing response were analyzed.

RESULTS: The median follow-up period was 48 months (range, 4 months to 13 years). Local control was obtained in 18/20 patients. The two local failures were salvaged, one by reirradiation and the other by surgery. Only one patient died of giant cell tumor, following extensive bone marrow infiltration. There was no serious late toxicity or malignant transformation. The response to radiotherapy was not influenced by disease status at presentation, tumor site, radiotherapy schedule, or presence of soft tissue extension.

CONCLUSIONS: Radiotherapy is effective in producing local control in primary as well as recurrent giant cell tumor of bone. There are no major complications and no significant risk of malignant transformation. Radiotherapy could be considered as the primary treatment modality in patients where surgery would produce functional deficits.