[The initial results in the fractionated 3-dimensional stereotactic irradiation of clivus chordomas]

The purpose of this study is to determine the impact of fractionated three-dimensional stereotactic radiotherapy on local tumor control and radiation induced side effects in patients with spheno-occipital chordoma.

13 patients with chordoma of the clivus (8 female, 5 male, median age at radiotherapy 42 years) were treated with a three-dimensional non-coplanar stereotactic irradiation technique using 15 MeV-photons. Median dose applied was 70 Gy. Irradiation was performed in 2 patients after biopsy and in 11 patients after resection of chordoma (2 R1-resections and 9 R2-resections).

After a median follow-up period of 32 months (4 to 80 months) 12 patients are alive (92%). One patient died 4 months after radiotherapy due to tumor progression. Three of the surviving patients developed local recurrence. Until now local tumor control is 69%. In two patients who had macroscopic tumor after surgery a complete regression occurred (verified by CT and MRI respectively). Early radiation complications were moderate, only headache and dizziness were observed. Also late radiation complications were low. Only one patient developed an endocrine dysfunction due to pituitary injury. Ongoing hormone replacement was necessary in this case. No patient developed sequelae of the optic system, cranial nerves or brain stem.

With regard to local tumor control our results are in the more favorable range compared to the results obtained with conventional photon irradiation techniques. In spite of the high doses applied both early and late radiation complications were in an acceptable range. Further adequate follow-up must prove, whether these promising results will be corroborated in the future.