Intensity-modulated radiotherapy of sacral chordoma--a case report and a comparison with stereotactic conformal radiotherapy.

In a case of partially resected sacral chordoma, the planning target volume (PTV) received 60 Gy and the gross target volume (GTV) 72 Gy using inversely planned, intensity-modulated, radiation therapy (IMRT). IMRT was compared with 3D-conformal radiotherapy (CRT). With IMRT, it was found that dose distribution is more homogeneous within the PTV outside the GTV and allows simultaneous dose escalation within the GTV. The volume of bowel receiving a dose higher than 40 Gy was reduced from 400 cc with CRT to 220 cc with IMRT. If particle therapy is not available, IMRT seems to be a promising alternative in the treatment of sacral chordomas.