Artikel
Usefulness of [18F]FET-PET for chemotherapy monitoring in non-contrast enhancing glioma
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Veröffentlicht: | 8. Juni 2016 |
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Gliederung
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Objective: Monitoring treatment response in non-contrast enhancing gliomas by means of conventional MRI can be difficult, as many patients show no radiological changes during therapy. Molecular imaging using [18F]FET-PET might detect metabolic changes within the tumour prior to structural volume reduction on MRI.
Method: 62 patients with a histologically proven grade II (n= 45) or grade III (n=17) glioma receiving alkylating chemotherapy with temozolomide or PCV were included. MRI and 18FET-PET investigations were scheduled prior to the beginning of chemotherapy and after 6 months. We analysed T2-volume as well as 18FET-PET based biological tumour volume (BTV) and maximal tumour-to-brain ratio (TBRmax). T2-volume, BTV and TBRmax changes of >-20% were classified as therapy response, while change of >+20% was regarded as therapy failure; all other patients were categorized as stable. Overall survival (OS) and progression free survival (PFS) times were calculated from beginning of therapy. Cox regression analysis was performed for outcome analysis, [18F]FET-PET and MRI parameter changes were assessed via t-test.
Results: During the follow-up time of 59.6 months, 10 patients out of 20 patients experiencing tumour progression had died. Mean OS time was 98.8 months, mean PFS time 77.4 months; median values were not reached yet. Response or failure assessed by BTV and TBRmax was highly associated with both PFS and OS (p<0.0001), while T2-volume based assessment was not associated with outcome (p=0.09 for PFS and p=0.21 for OS). PFS time in patients classified as responders according to a BTV reduction of >-20% was 91.0 months, compared to 43.0 months in patients rated as stable and 19.3 months in patients with a BTV increase of >+20%.
Conclusions: [18F]FET-PET-based monitoring provides an additional possibility to assess metabolic changes in glioma patients undergoing chemotherapy and might help to identify non-responders.