PET in the clinical management of glioma: Evidence map

OBJECTIVE. Several studies have assessed PET to complement the anatomic information obtained from other imaging modalities in various clinical contexts for the management of glioma. We constructed an evidence map of clinical evidence on the use of PET in glioma and identified research gaps. MATERIALS AND METHODS. We searched PubMed and Scopus (from inception through June 30, 2011) to identify studies assessing the use of PET for glioma regardless of setting of care or indication. We extracted test OBJECTIVEs, study characteristics, and phases of diagnostic evidence and then assessed research diversity and temporal trends in the literature. We excluded studies assessing only technical feasibility and optimization of PET. RESULTS. A total of 129 studies were considered eligible; the number of articles published annually has greatly increased over time (p for trend < 0.001). Most studies (n = 118, 91%) assessed diagnostic or prognostic performance; fewer studies reported on the impact of PET on diagnostic thinking (n = 4, 3%), therapeutic decisions (n = 4, 3%), or patient-relevant clinical outcomes (n = 3; 2%). Fluorine-18 FDG (n = 73, 57%) or 11C-methionine (n = 44, 34%) were the two most commonly evaluated PET tracers. Pretherapy assessment (n = 72, 56%) and monitoring of treatment response (n = 48, 37%) were the most common settings of test use assessed in the research studies. CONCLUSION. More primary studies, particularly studies of newer tracers focusing on biopsy or treatment planning, are needed to better characterize the role of PET in specific contexts.