Preliminary novalis experience in the treatment of skull base chordomas with stereotactic radiosurgery and stereotactic radiotherapy

Purpose: The treatment of chordomas is challenging. The role of radiation therapy in addition to Surgery is well established. Different techniques have been applied aiming to improve turner local control. This is the first report using shaped beam and intensity modulation radiotherapy (IMRT) with Novalis. The purpose of this new technique is to allow higher doses to be delivered to the tumor without damaging vital structures close to the lesion. Materials and Methods: Eight patients with histologically confirmed diagnosis of chordoma were treated with Novalis in a single dose or in a fractionated regimen. Three patients were treated with stereotactic radiosurgery (SRS), 1 with hypofractionated radiotherapy (HSRT) and 4 were treated with fractionated radiotherapy (FSRT). There were 5 males and 3 females, median age was 60 year. Median follow-up for SRS cases was 30 months, 28 months for HSRT and 24 months for FSRT. Volumes and dose range for optic apparatus and brainstem were evaluated. Results: Local tumor control was achieved in all cases. Chordomas remained stable with SRS and HSRT. In the FSRT group, two lesions disappeared, one decreased in size and the other was stable. Same volume tumors submitted either to SRS or fractionation presented different responses. Also tumors receiving the same radiation dose but with different volumes showed different behavior. Doses delivered to eloquent structures were superior to tolerable doses described in the literature. No complications due to high doses of radiation were detected. Conclusion: All three methods offered satisfactory local control. Fractionated schemes seem to provide better tumor response since disappearance and decrease in tumor size were only observed in this group. Shaped beam and IMRT techniques allowed a higher dose to the tumor than conventionally given and still sparing damage to adjacent structures. Copyright (C) 2004 S. Karger AG, Basel.