Purpose: The aim of this paper is to evaluate efficacy of radiotherapy for giant cell tumor of bone given either postoperatively or as sole treatment, and to assess prognostic factors for treatment outcome.
Methods and materials: The study includes 37 patients. In 9 cases, soft tissue involvement was noted. Nonradical operation followed by radiotherapy was given to 23 patients, and 14 patients received irradiation only. Total dose of 39--64 Gy was delivered. The average follow-up was 5 years. Probability of local tumor control (LTC) depending on the treatment strategy was calculated, and prognostic factors were assessed.
Results: LTC was noted in 31 cases. Ten-year LTC for surgery with irradiation was 83% and 69% for radiotherapy alone; however, this difference was not statistically significant. For tumors smaller than 4 cm LTC probability was above 90%, and it decreased to less than 60% for tumors larger than 8.5 cm. No dose-response relationship has been found. In 7 cases, late normal tissue effect occurred.
Conclusions: Giant cell tumors of bone can be considered as radiosensitive and radiotherapy with total dose of 40--45 Gy seems to be an effective sole treatment especially for tumors smaller than 4 cm in diameter. For larger tumors, surgery combined with postoperative radiotherapy should be considered.