Radiotherapy for chordomas and low-grade chondrosarcomas of the skull base with carbon ions.
OBJECTIVE
Compared to photon irradiation, carbon ions provide physical and biologic advantages that may be exploited in chordomas and chondrosarcomas.


METHODS
Between August 1998 and December 2000, 37 patients with chordomas (n = 24) and chondrosarcomas (n = 13) were treated with carbon ion radiotherapy within a Phase I/II trial. Tumor conformal application of carbon ion beams was realized by intensity-controlled raster scanning with pulse-to-pulse energy variation. Three-dimensional treatment planning included biologic plan optimization. The median tumor dose was 60 GyE (GyE = Gy x relative biologic effectiveness).


RESULTS
The mean follow-up was 13 months. The local control rate after 1 and 2 years was 96% and 90%, respectively. We observed 2 recurrences outside the gross tumor volume in patients with chordomas. Progression-free survival was 100% for chondrosarcomas and 83% for chordomas at 2 years. Partial remission after carbon ion radiotherapy was observed in 6 patients. Treatment toxicity was mild.


CONCLUSIONS
These are the first data demonstrating the clinical feasibility, safety, and effectiveness of scanning beam delivery of ion beams in patients with skull base tumors. The preliminary results in patients with skull base chordomas and low-grade chondrosarcomas are encouraging, although the follow-up was too short to draw definite conclusions concerning outcome. In the absence of major toxicity, dose escalation might be considered.
Schulz-Ertner
Daniela
D
Department of Radiation Oncology, University of Heidelberg, INF 400, Heidelberg 69120, Germany. d.ertner@dkfz-heidelberg.de
Haberer
Thomas
T
Jäkel
Oliver
O
Thilmann
Christoph
C
Krämer
Michael
M
Enghardt
Wolfgang
W
Kraft
Gerhard
G
Wannenmacher
Michael
M
Debus
Jürgen
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes / Q000627:therapeutic use*; D002813:Chondrosarcoma / Q000532:radiotherapy*; D002817:Chordoma / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019292:Skull Base Neoplasms / Q000532:radiotherapy*; D013238:Stereotaxic Techniques
D002250:Carbon Radioisotopes