Abstract
PurposePET using radiolabeled amino acid [18F]-fluoro-ethyl-L-tyrosine (FET-PET) is a well-established imaging modality for glioma diagnostics. The biological tumor volume (BTV) as depicted by FET-PET often differs in volume and location from tumor volume of contrast enhancement (CE) in MRI. Our aim was to investigate whether a gross total resection of BTVs defined as < 1 cm3 of residual BTV (PET GTR) correlates with better oncological outcome.MethodsWe retrospectively analyzed imaging and survival data from patients with primary and recurrent WHO grade III or IV gliomas who underwent FET-PET before surgical resection. Tumor overlap between FET-PET and CE was evaluated. Completeness of FET-PET resection (PET GTR) was calculated after superimposition and semi-automated segmentation of pre-operative FET-PET and postoperative MRI imaging. Survival analysis was performed using the Kaplan–Meier method and the log-rank test.ResultsFrom 30 included patients, PET GTR was achieved in 20 patients. Patients with PET GTR showed improved median OS with 19.3 compared to 13.7 months for patients with residual FET uptake (p = 0.007; HR 0.3; 95% CI 0.12–0.76). This finding remained as independent prognostic factor after performing multivariate analysis (HR 0.19, 95% CI 0.06–0.62, p = 0.006). Other survival influencing factors such as age, IDH-mutation, MGMT promotor status, and adjuvant treatment modalities were equally distributed between both groups.ConclusionOur results suggest that PET GTR improves the OS in patients with WHO grade III or IV gliomas. A multimodal imaging approach including FET-PET for surgical planning in newly diagnosed and recurrent tumors may improve the oncological outcome in glioma patients.
Highlights
Gliomas are the most common primary tumors of the central nervous system after meningiomas, showing a prevalence rate of 47.6 per 100.000, and a worldwide annual incidence of 4–6 cases per 100,000 [1, 2], constantly increasing during the last two decades [3]
Using a semi-automated segmentation algorithm, we firstly looked for differences between tumor extension of preoperative biological tumor volume (BTV) in FET-PET and contrast enhancement (CE) MRI; and secondly investigated how complete or nearcomplete removal of BTV (= PET-gross total resection (GTR)) defined as < 1 cm3 calculated residual BTV influences overall survival (OS)
Biological tumor volume defined by FET‐PET corresponds only partially to the CE delineation of the tumor
Summary
Gliomas are the most common primary tumors of the central nervous system after meningiomas, showing a prevalence rate of 47.6 per 100.000, and a worldwide annual incidence of 4–6 cases per 100,000 [1, 2], constantly increasing during the last two decades [3]. The WHO 2016 classification of tumors of the central nervous system classifies diffuse gliomas into WHO grade II and III astrocytoma, WHO grade. II and III oligodendroglioma and grade IV glioblastoma [4]. The additional introduction of molecular markers like IDH mutation and 1p/19q co-deletion [8] has shown that the genetic background plays a pivotal role for oncological prognosis and treatment response, making them indispensable for tumor classification [4, 9, 10]. The treatment of patients with glioma of the WHO grades III or IV encompasses surgical resection, followed by radiotherapy and chemotherapy [11, 12]. Surgical resection plays a pivotal role in the glioma treatment by improving both,
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