18F-FET-PET-guided gross total resection improves overall survival in patients with WHO grade III/IV glioma: moving towards a multimodal imaging-guided resection

Abstract

Purpose PET 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. Methods We 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. Results From 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. Conclusion Our 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.

Amino acid PET-MRI of malignant gliomas for biopsy planning

“…The histopathological results obtained from material collected from early FET-avid areas outside contrast enhancement in MRI showed 100% agreement with the nal histopathological diagnosis, con rming the reliability of FET-PET imaging and the value of PET and MRI image fusion for biopsy planning, surgery, and radiotherapy. Indeed, tumor resection based on FET-PET has been associated with a better prognosis in patients with higher-grade gliomas 19 , and residual tumor volume in postoperative PET-FET images was an important prognostic factor in patients with GBM [20][21][22] . Recently, we also showed encouraging results of radiotherapy with a boosted radiation dose based on early and late PET images 23 .…”

Recapitulating the Key Advances in the Diagnosis and Prognosis of High-Grade Gliomas: Second Half of 2021 Update

“…Whether a gross total resection (GTR) of the biological tumor volume, defined as <1 cm 3 of residual volume (PET-guided GTR), correlates with better outcomes for the patients was investigated by Ort and co-workers [ 55 ]. Patients undergoing PET-guided GTR at initial or recurrent resections showed longer OS, with a median of 19.3 months versus 13.7 months for patients with residual PET ( Figure 4 g).…”

Amino Acid Tracer PET MRI in Glioma Management: What a Neuroradiologist Needs to Know

“…The results were consistent regardless of age, MGMT, IDH mutation, promoter, or adjuvant therapy regimens. 17 High-and low-grade subregions may coexist in gliomas. HGGs demonstrate higher uptake of AATs than LGGs.…”