Dose-escalated conformal radiotherapy of glioblastomas -- results of a retrospective comparison applying radiation doses of 60 and 70 Gy.
BACKGROUND
Dose escalated three-dimensional conformal radiotherapy with 70 Gy against glioblastomas was compared retrospectively with the standard scheme of 60 Gy using 2-D-planning.


METHODS
In the period from 1994 to 1998, a series of 135 patients with glioblastomas was treated by surgery and postoperative radiotherapy. A conversion from 2-D into 3-D-planning was carried out in 4/1996. The prescribed total dose for the first 65 patients was 60 Gy (group 60). A boost up to 70 Gy was added for the remaining 70 patients (group 70).


RESULTS
The median survival time was 8.0 months for group 60 and 8.3 months for group 70. A dependency on the applied dose range was found. The median survival time was 3 months for patients who received a radiation dose of 55 Gy or less, 8.6 months for doses between 56 and 65 Gy, and 9.6 months for patients with a dose between 66 and 75 Gy (p < 0.01). In a multivariate analysis only the performance status maintained significance (p = 0.02) as a prognostic factor, while the dose range reached borderline significance (p = 0.09).


CONCLUSIONS
No statistically significant survival prolongation was reached despite a dose escalation to 70 Gy.
Graf
Reinhold
R
Centre of Radiation Medicine, Humboldt-University, Berlin, Germany. reinhold.graf@charite.de
Hildebrandt
Bert
B
Tilly
Wolfgang
W
Sreenivasa
Geetha
G
Ullrich
Renate
R
Felix
Roland
R
Wust
Peter
P
Maier-Hauff
Klaus
K
D001932:Brain Neoplasms / Q000401:mortality* / Q000532:radiotherapy*; D015897:Comorbidity; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005858:Germany / Q000453:epidemiology; D005909:Glioblastoma / Q000401:mortality* / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011832:Radiation Injuries / Q000401:mortality*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013534:Survival; D016019:Survival Analysis; D016896:Treatment Outcome