Re-irradiation of recurrent glioblastoma multiforme using 11C-methionine PET/CT/MRI image fusion for hypofractionated stereotactic radiotherapy by intensity modulated radiation therapy

Abstract

BackgroundThis research paper presents a valid treatment strategy for recurrent glioblastoma multiforme (GBM) using hypofractionated stereotactic radiotherapy by intensity modulated radiation therapy (HS-IMRT) planned with 11C-methionine positron emission tomography (MET-PET)/computed tomography (CT)/magnetic resonance imaging (MRI) fusion.MethodsTwenty-one patients with recurrent GBM received HS-IMRT planned by MET-PET/CT/MRI. The region of increased amino acid tracer uptake on MET-PET was defined as the gross tumor volume (GTV). The planning target volume encompassed the GTV by a 3-mm margin. Treatment was performed with a total dose of 25- to 35-Gy, given as 5- to 7-Gy daily for 5 days.ResultsWith a median follow-up of 12 months, median overall survival time (OS) was 11 months from the start of HS-IMRT, with a 6-month and 1-year survival rate of 71.4% and 38.1%, respectively. Karnofsky performance status was a significant prognostic factor of OS as tested by univariate and multivariate analysis. Re-operation rate was 4.8% for radiation necrosis. No other acute or late toxicity Grade 3 or higher was observed.ConclusionsThis is the first prospective study of biologic imaging optimized HS-IMRT in recurrent GBM. HS-IMRT with PET data seems to be well tolerated and resulted in a median survival time of 11 months after HS-IMRT.

Therapeutic options in recurrent glioblastoma—An update

“…Radiosurgery is less frequently used in glioblastoma. As favorable variables for selecting patients likely to benefit from re-irradiation again general prognostic factors such as young age, high KPS or small tumor size have been proposed [32,[34][35][36][37]. Different reports exist regarding the preferred time interval to initial radiation for benefit from re-irradiation, favoring either an interval of less than 6 months [35] or more than 6 or even 12 months [37,38].…”

Tumour progression or pseudoprogression? A review of post-treatment radiological appearances of glioblastoma

“…These include 11 Most research has been conducted using C-Met-PET (Fig 6). 78 This biomarker has been found to show increased uptake in a range of cerebral malignancies when compared to benign lesions (including radiation necrosis) with a sensitivity of 92% and a specificity of 100%. 79 It has also been shown to be more sensitive than FDG-PET 80 ; however, studies into whether C-Met-PET is useful for differentiating between tumour progression and pseudoprogression have been contradictory or suffered from a small patient sample.…”

PET/MRI and brain tumors: focus on radiation oncology treatment planning

“…Early-phase nonrandomized clinical trials have been undertaken to further investigate the possible impact of implementing AA-PET in dose-intensified radiotherapy treatment planning for HGG at initial diagnosis [27,28], but failed to show a clear clinical benefit in terms of progression-free or overall survival. This could potentially be explained by the fact that for over 90 % of the patients [29], the FET-PET-positive volume can be found inside the clinical target volume (CTV) based on contrast-enhancement in T1-weighted MRI with 20 mm margin [30].…”