Adding 11C-methionine PET to the EORTC prognostic factors in grade 2 gliomas

Purpose The management of adult patients with grade 2 gliomas remains a challenge for the clinical neuro-oncologist. Several clinical prognostic factors appear to be as important as treatment factors in determining outcome. From the European Organisation for Research and Treatment of Cancer (EORTC) trials 22844 and 22845, a prognostic scoring system has been proposed based on the presence of unfavourable prognostic factors. The aim of the present study was to assess the additional prognostic value of C-11-methionine (MET) measured by positron emission tomography (PET) in the setting of the EORTC prognostic scoring system. Methods In this retrospective review, 129 patients with supratentorial grade 2 gliomas were subjected to a PET study as part of the pre-treatment tumour investigation. One hundred and three cases were classified as low-risk patients (0-2 unfavourable factors) and 26 cases as high-risk patients (3-5 unfavourable factors) according to the EORTC criteria. MET PET was evaluated as an extra prognostic factor in both groups. Results In the high-risk group, patients with high MET uptake had a worse outcome than patients with low MET uptake. A similar trend was found for the low-risk group in patients with oligodendrocytic tumours. Conclusions Our findings further strengthen the role of MET PET as an important prognostic tool in the management of this group of patients.