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Prospective Phase II Study of Radiotherapy Dose Escalation in Grade 4 Glioma Using 68 Ga-Pentixafor PET Scan.

Authors :
Madan R
Kumar N
Dracham CB
Kumar R
Trivedi G
Tripathi M
Sahoo SK
Singla N
Ahuja CK
Chatterjee D
Yadav A
Goyal S
Khosla D
Source :
Clinical oncology (Royal College of Radiologists (Great Britain)) [Clin Oncol (R Coll Radiol)] 2024 Sep; Vol. 36 (9), pp. e294-e300. Date of Electronic Publication: 2024 Apr 27.
Publication Year :
2024

Abstract

Aims: Local failure remains the major concern in grade 4 glioma or glioblastoma (GBM). Pilot studies have shown a radiotherapy (RT) dose-response relationship in GBM. Here we present our preliminary data of RT dose escalation using <superscript>68</superscript> Ga-Pentixafor PET scan. High <superscript>68</superscript> Ga-pentixafor uptake in glioma cells helps in sharp demarcation between tumour and normal brain.<br />Materials and Methods: This phase II prospective study was conducted from 2018 to 2020. Thirty, biopsy-proven cases of grade 4 glioma were included. All patients underwent post-operative MRI of the brain and <superscript>68</superscript> Ga-Pentixafor PET scan. RT was planned in 2-phases. Phase-1 GTV (GTV1) comprised of T2/flair abnormality, PET-avid disease and post-op cavity. A margin of 2cm was given to GTV-1 to create phase-1 CTV (CTV1), which was further expanded to 0.5cm to generate phase-1 PTV (PTV1). A radiation dose of 46Gy/23fr was prescribed to PTV-1. Phase-2 GTV (GTV2) consisted of CT/MRI contrast-enhancing lesion, PET avid disease and post-op cavity. A margin of 0.5 cm was given to GTV2 to create phase-2 CTV (CTV2) which was expanded to 0.5 cm to create phase-2 PTV (PTV2). RT dose of 14 Gy/7 fr was prescribed to PTV2. PET avid disease was delineated as GTV PET and a margin of 3mm was given to generate PTV-PET which received escalated RT dose of 21 Gy/7fr by simultaneous integrated boost (SIB) in phase 2 (Total dose to PTV PET = 67 Gy/30 fr). All patients received concurrent and adjuvant temozolomide. The data was prospectively maintained in Microsoft Excel sheet. SPSS v 23 was used for statistical analysis. The primary endpoints were estimation of the overall survival (OS) and progression-free survival (PFS), and secondary endpoint was to measure the incidence of radiation necrosis. Categorical variables were reported as frequency and percentage and quantitative variables were reported as median and range.<br />Results: Data from thirty patients were analysed. A median OS of 23 months was observed with estimated 1, 2 and 3 years OS of 90%, 40% and 17.8% respectively. A significant association of OS was seen with the extent of surgery (p = 0.04) and kernofsky performance status (p = 0.007). No patient developed significant radiation necrosis.<br />Conclusions: The index study did not show any survival benefit from dose escalation RT. However, all of the patients tolerated the treatment well and none of them developed radiation necrosis. Considering the small sample size as a limitation of the index study, the role of <superscript>68</superscript> Ga-pentixafor PET scan for radiation dose escalation should be further explored.<br />Clinical Trial Number: CTRI/2019/05/019146.<br /> (Copyright © 2024. Published by Elsevier Ltd.)

Details

Language :
English
ISSN :
1433-2981
Volume :
36
Issue :
9
Database :
MEDLINE
Journal :
Clinical oncology (Royal College of Radiologists (Great Britain))
Publication Type :
Academic Journal
Accession number :
38821722
Full Text :
https://doi.org/10.1016/j.clon.2024.04.011