3D-recurrence-patterns of glioblastomas after CT-planned postoperative irradiation.
OBJECTIVE
The introduction of computed-tomography as an advanced planning tool for the irradiation of intracranial tumours led to a controversial discussions about the optimal target-volume for the primary and postoperative treatment of malignant gliomas. This study analyses the three-dimensional tumour regrowth pattern relative to the treated volume which included the macroscopic preoperative tumour and 2-cm safety margin.


METHODS
Seventy-nine patients with histologically-confirmed Glioblastoma multiforma and documented recurrence who were irradiated in our department between 1990 and 1996 were reviewed. With the help of a computer program written for this purpose, the PTV of the CT-based treatment plan was reconstructed and its spatial outline compared with the reconstructed volume of the recurrent tumour in the control CT-study.


RESULTS
In 33 out 34 patients for which the CT-study showing tumour-recurrence was available the recurrence was completely situated within the original 90%-isodose. Only one tumour surpassed the outside surface of the PTV but was predominantly situated within the original tumourbed and suggests a tumour-regrowth within the high dose volume.


CONCLUSIONS
The above results show that target-volumes based on the preoperative size of the enhanced tumour mass well cover the site of recurrence in nearly all cases. The findings suggest dose escalation to a more restricted volume.
Oppitz
U
U
Department of Radiation Oncology, University of Würzburg, Germany.
Maessen
D
D
Zunterer
H
H
Richter
S
S
Flentje
M
M
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D018714:Radiotherapy, Adjuvant; D011881:Radiotherapy, Computer-Assisted; D014057:Tomography, X-Ray Computed