Reducing clinical target volume margins for multifocal glioblastoma: a multi-institutional analysis of patterns of recurrence and treatment response
- Author:
Francesco MARAMPON
1
;
Giovanni Luca GRAVINA
;
Elisa CINELLI
;
Lucy ZACCARO
;
Miriam TOMACIELLO
;
Nunzia Di MEGLIO
;
Francesco GENTILI
;
Alfonso CERASE
;
Armando PERRELLA
;
Mariya YAVORSKA
;
Sami ABURAS
;
Luciano MUTTI
;
Maria Antonietta MAZZEI
;
Giuseppe MINNITI
;
Paolo TINI
Author Information
- Publication Type:Original Article
- From:Radiation Oncology Journal 2025;43(1):13-21
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:No guidelines exist to delineate radiation therapy (RT) targets for the treatment of multiple glioblastoma (mGBM). This study analyzes margins around the gross tumor volume (GTV) to create a clinical target volume (CTV), comparing response parameters and modalities of recurrence.Material and Methods: One-hundred and three mGBM patients with a CTV margin of 2 cm (GTV + 2.0 cm) or 1 cm (GTV + 1.0 cm) were retrospectively analyzed. All patients received a total dose of 59.4–60 Gy in 1.8-2.0 Gy daily fractions, delivered from 4 to 8 weeks after surgery, concomitantly with temozolomide (75 mg/m2). Overall survival (OS) and progression-free survival (PFS) were calculated from the date of surgery until diagnosis of disease progression performed by magnetic resonance imaging and classified as marginal, in-field, or distant, comparing site of progression with dose distribution in RT plan.
Results:OS in mGBM CTV1 group was 11.2 months (95% confidence interval [CI], 10.3–12.1), and 9.2 months in mGBM CTV2 group (95% CI, 9.0–11.3). PFS in mGBM CTV1 group occurred within 8.3 months (95% CI, 7.3–9.3), and 7.3 months in mGBM CTV2 group (95% CI, 6.4–8.1). No difference was observed between the two groups in terms of OS and PFS time distribution. Adjusted to a multivariate Cox risk model, epidermal growth factor receptor amplification resulted a negative prognostic factor for both OS and PFS.
Conclusion:In mGBM, the use of a 1 cm CTV expansion seems feasible as it does not significantly affect oncological outcomes and progression outcome.
