Stereotactic fractionated radiotherapy for chordomas and chondrosarcomas of the skull base

Purpose: To investigate the treatment outcome of patients suffering from sk ull base chordoma or chondrosarcoma after fractionated stereotactic radioth erapy. Methods and Materials: We report 45 patients treated for chordoma or chondr osarcoma with postoperative fractionated stereotactic radiotherapy between 1990 and 1997, Patients had CT and MRI for 3D treatment planning performed under stereotactic guidance. Median dose at isocenter was 66.6 GS for chord omas and 64.9 Gy for chondrosarcomas. MRI imaging was obtained in intervals after therapy to evaluate local relapse. Survival was calculated according to the Kaplan-Meier method. Results: All chondrosarcomas had achieved and maintained local control and recurrence-free status at follow-up of 5 years, Local control rate of chord omas was 82% at 2 years and 50% at 5 years. Survival was 97% at 2 years and 82% at 5 years, At maximum follow-up of 8 years local control and survival rate of chordomas was 40% (82%). Clinically significant late toxicity deve loped in one patient. Conclusions: Our results demonstrate the feasibility of fractionated photon beam therapy and its success in the treatment of skull base tumors. Modern 3D treatment techniques provide superior results compared to conventional techniques. The role of high-precision radiotherapy compared to particle be am therapy in the treatment of these tumors is not yet fully clear and furt her research is needed. (C) 2000 Elsevier Science Inc.