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.
Highlights
Accepted: 5 March 2021Gastrointestinal stromal tumor (GIST), the most common mesenchymal tumor of the gastrointestinal (GI) tract, has an annual incidence of 6.8–14.5 per million individuals [1,2,3].gastrointestinal stromal tumor (GIST) are often considered resistant to chemotherapy and are insensitive to irradiation; further, the lack of effective treatments and its metastatic nature generally results in a poor prognosis [4,5,6,7]
GIST usually develops from oncogenic mutations in the tyrosine kinase receptor KIT (CD117) [8], and/or platelet-derived growth factor receptor-α (PDGFRα) [9]; the identification of c-KIT and PDGFR-α has resulted in the establishment of new therapeutic approaches based on therapies targeting the receptors, namely, molecular targeted therapy (MTT)
When compared with those of CT, the diagnostic performance of [18F]FDG positron emission tomography (PET) or PET/CT was excellent in assessing the treatment response to MTT in GIST
Summary
Accepted: 5 March 2021Gastrointestinal stromal tumor (GIST), the most common mesenchymal tumor of the gastrointestinal (GI) tract, has an annual incidence of 6.8–14.5 per million individuals [1,2,3].GISTs are often considered resistant to chemotherapy and are insensitive to irradiation; further, the lack of effective treatments and its metastatic nature generally results in a poor prognosis [4,5,6,7]. GIST usually develops from oncogenic mutations in the tyrosine kinase receptor KIT (CD117) [8], and/or platelet-derived growth factor receptor-α (PDGFRα) [9]; the identification of c-KIT and PDGFR-α has resulted in the establishment of new therapeutic approaches based on therapies targeting the receptors, namely, MTT. After the introduction of tyrosine kinase inhibitors (TKIs), such as imatinib methylate in 2001 for GIST treatment, the prognosis and therapeutic outcome of this tumor entity have considerably improved. The introduction of molecular targeted therapy (MTT) in GIST has improved the prognosis and therapeutic outcome; the expensiveness of the treatment has increased the importance of appropriate diagnostic tools, encouraging early assessment and confirmation of a therapeutic response
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