Additional Value of [18F]FDG PET or PET/CT for Response Assessment of Patients with Gastrointestinal Stromal Tumor Undergoing Molecular Targeted Therapy: A Meta-Analysis

Abstract

To assess the additional value of 2-deoxy-2-[¹⁸F] fluoro-d-glucose ([¹⁸F]FDG) positron emission tomography (PET) or PET/CT over conventional morphological imaging techniques in the treatment response assessment of gastrointestinal stromal tumor (GIST) to molecular targeted therapy (MTT), we performed a meta-analysis of all the available studies to compare the predictive value of [¹⁸F]FDG PET or PET/CT and conventional imaging techniques for assessing the response to MTT in GIST. We determined the sensitivities and specificities across studies, we calculated the positive and negative likelihood ratios (LR) and made summary receiver operating characteristic curves (SROC) using hierarchical regression models. Pooled analysis included 4 studies comprising 88 patients. The performance characteristics in [¹⁸F]FDG PET or PET/CT and CT were as follows: sensitivity, 89% (95% confidence interval (CI) 78, 95), 52% (39, 64); specificity, 65% (44, 83), 92% (75, 99); diagnostic odds ratios (DOR), 5.8 (2.0, 16.8 4.9 (1.5, 16.1); positive LR, 1.9 (1.1, 3.4), 3.0 (1.1, 8.1); and negative LR, 0.23 (0.03, 1.6), 0.66 (0.42, 1.0), respectively. In SROC curves, the area under the curve (AUC) was 0.81 (SE, 0.11) and 0.71 (SE, 0.13) and the Q* index was 0.74 and 0.66, respectively. [¹⁸F]FDG PET/CT had higher sensitivity, while DOR and SROC curves showed better diagnostic performance in [¹⁸F]FDG PET and PET/CT studies as compared to CT.

Keywords: GIST; PET/CT; [18F]FDG PET; molecular targeted therapy; treatment response assessment.

Figure 1

PRISMA flow diagram of included articles. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Figure 2

Quality assessment of the included studies using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

Figure 3

Forest plots (of sensitivity and specificity) of [¹⁸F]FDG PET or PET/CT and CT and pooled the diagnostic performance of the imaging techniques. For each test, we combined the SROC curves and their corresponding findings.

Figure 4

Summary receiver operating characteristic (SROC) curve for the diagnostic performance of [¹⁸F]FDG PET or PET/CT (black curve) and CT (red curve). The size of the circle diamond indicates the weight of each study in [¹⁸F]FDG PET or PET/CT and CT, respectively. The area under the SROC curve is 0.81 for [¹⁸F]FDG PET or PET/CT and 0.76 for CT.