Combined radiotherapy and razoxane in the treatment of chondrosarcomas and chordomas

Background: Chondrosarcomas and chordomas are reported to have low radio-sensitivity. Therefore, a study was undertaken to explore the radioresponsiveness of these tumours using the sensitising agent razoxane. Patients and Methods: Thirteen chondrosarcomas and five chordomas were irradiated with high-energy photons and razoxane in the period from 1984 to 2003. The median tumour dose was 60 Gy in the chondrosarcomas and 63 Gy in chordomas. Razoxane tablets were given at a dose of 125 mg twice daily starting 5 days before the first irradiation. The drug was continued on radiation days. Results: Eight out of the 13 chondrosarcomas had unresectable or recurrent measurable disease. There were one complete and five partial responses, while two tumours remained unchanged (response rate 75%). The median duration of response was 22 months. Three out of four patients without clear surgical margins and one patient with clear margins had locally controlled disease. Overall, local control was achieved in seven out of twelve patients who were not radically resected. All five patients with chordomas survived 5 years and remained locally controlled at that time. Among four measurable tumours, two complete and one partial regression were noted. Razoxane was well tolerated; the dose limiting toxicity was leukopenia. Conclusion: Photon irradiation together with razoxane induces major responses in a majority of patients with chondrosarcomas and chordomas. This combination therapy seems to be more effective than photon irradiation alone.