ESTRO 2024 - Abstract Book

S840

Clinical - CNS

ESTRO 2024

Results:

Pretreatment MRI mean ED value was associated with a statistically significant analysis and an increasing trend of mean values during and one month after the treatment (table 2). During follow up 9 patients (16,9%) experienced RN that was associated with a significant increase in ED on one month post treatment MRI. An increase in the re irradiation time interval between the first radiation treatment and re-PT was shown to be related with decrease ED values on planning MRI as well as a positive correlation between increase ED value at planning MRI with increasing GTV re- PT volume. The median OS was significantly higher in patient without onset of RN. The use of steroid before re-PT was associated with worse OS and PFS. No statistical impact in OS or PFS and increase of steroid dose during re- PT was seen, as well as between MRI edema values at baseline, mid-therapy, end and one month and increase of steroids.

Wilcoxon signed rank sum test (p value

Edema

Mean

SD

Median

IQR

Comparison

Edema (cm3) on planning

Edema (cm3) on planning MRI

48,77

44,15

36,88

41,84

0,0003

MRI vs. Edema (cm3) on mid treatment MRI Edema (cm3) on planning MRI vs Edema (cm3) on end of treatment MRI Edema (cm3) on planning MRI vs Edema (cm3) on MRI 1 month after the treatment Edema (cm3) on end of treatment MRI vs Edema (cm3) on MRI 1 month after the treatment

Edema (cm3) on mid treatment MRI

59,79

49,78

45,30

56,16

0,0022

Edema (cm3) on end of treatment MRI

60,28

45,15

45,15

60,10

0,0088

Edema (cm3) on MRI 1 month after the treatment

61,86

48,38

44,40

72,89

0,7367

Table 2: Variation and comparison of edema during and after re- PT

Conclusion:

The current study was conducted to analyse for the first time the variation of radiation induced ED before, during and after re-PT of rHGG demonstrating that re-PT is a safe and effective treatment for rHGG and ED can be a predictive and prognostic factor for the onset of RN.