Trial Information

Assessment of 18Fluoro-thymidine PET-CT for the Volume Definition of High-grade Gliomas (GLIO-TEP) : Correlation With Histopathology

- Background: 18FDG is the most widely used tracer for oncologic positron emission
tomography (PET). However, the high glucose utilization of normal gray matter limits
its utility in brain explorations. More recently, 18FLT was introduced as a PET tracer
for tumor imaging. It has been found useful for non-invasive assessment of the
proliferation status of various tumors. Its potential clinical use in the evaluation of
brain tumors has not been clearly determined because of sparse studies.

- The primary objective of this study is to assess the positive predictive value of
PET-CT uptake of 18FLT in diagnosing malignant tissue by comparison with the
histopathological gold standard diagnosis according to the WHO grading malignancy scale
and the Ki-67 proliferation index, at the time of preoperative evaluation.

- Secondary objectives are: to describe and compare preoperative tumor volumes and
postoperative residual tumor volumes as assessed by 18FLT PET-CT and MRI, and to
describe a quantitative proliferation index with PET (SUV for "standardized uptake
value").

- Study design: This is an exploratory cross-sectional study at two separate times:
pre-and postoperative. Eligible patients will be included consecutively. Histological
samples will be analyzed blindly to imaging data. Assessments of PET-CT and MRI volumes
will be blind to each other.

- Procedure: After information and written informed consent and before surgery, patients
will undergo MRI and 18F-FLT PET-CT to obtain the tumor volume according to both
modalities. Then, surgeons will make different biopsies from i) areas with MR
abnormalities and FLT uptake, ii) area with FLT uptake and no MR abnormality (on the
surgery approach way or in not functional areas), iii) area with MR abnormality without
any FLT uptake, iiii) area without any uptake where biopsy is possible because the area
is on the surgery approach way. Then, the samples will be blindly analyzed to determine
the Ki-67 proliferation index and WHO grading malignancy scale. Patients will undergo
again 18F-FLT PET-TDM and MRI at least 4 weeks after surgery, in the week preceding
radiotherapy, to determine residual tumor volumes.