ESTRO 2024 - Abstract Book

S838

Clinical - CNS

ESTRO 2024

1358

Digital Poster

Radiation induced edema and radionecrosis in re-irradiation of rHGG treated with PT: Final analysis

Ana Turkaj 1 , Daniele Scartoni 1 , Riccardo Pertile 2 , Paola Feraco 3 , Francesco Fellin 1 , Mirko Lipparini 1 , Luca Pomino 1 , Marco Cianchetti 1 , Dante Amelio 1 1 Proton Therapy Center, Azienda Provinciale per i Servizi Sanitari, Trento, Italy. 2 Trento Health Service, Clinical and Evaluative Epidemiology, Trento, Italy. 3 S. Chiara Hospital, Radiology, Trento, Italy

Purpose/Objective:

During and after re-irradiation of recurrent high-grade gliomas (rHGG) variation of edema (ED) is frequent. The aim of study is to report a quantitative analysis of radiation induced ED analyzing the temporal changes before, during and after proton therapy re-irradiation (re-PT) and correlation with Radionecrosis (RN), as well as to evaluate use of prognostic factors with impact change ED values and correlation on survival (OS) and progression-free survival (PFS).

Material/Methods:

Fifty-three patients with rHGG were re-irradiated with active scanning PT at our institution and included in the study (table 1). ED was drowned on 212 MRI scans and was quantified as any T2w and FLAIR changes excluding the Gross Tumor Volume. Radiation induced imaging changes were defined as new areas of increased T2w and FLAIR signal surrounding the treated GTV on MRI imaging ((fig. 1: example of patient with RN). We analyzed the temporal change of ED at baseline, mid, end and one month after re-PT and onset of RN as well as prognostic factors such: steroids, median time to re-PT, number of different lines of chemo before or concurrent chemo re-PT association, recurrence location disease site, histology and GTV re-PT volume with impact change ED values and correlation on OS and PFS.

N°of patients

53 (36 male, 17 female)

Median age of Re-irradiation

50 (30-69)

Performance status [KPS]

60-100

Histology GBM AA

32

(60

%)

21 (40 %)

Site

of

recurrence

Right

frontal

Left

frontal

14 10

Right

temporal

Right

occipital

8 5 5

Left

temporal

Right

parietal