The Usefulness of Preoperative 18FDG Positron-Emission Tomography and Computed Tomography for Predicting the Malignant Potential of Gastrointestinal Stromal Tumors

Abstract

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The tumor size and mitotic count, typical risk category factors, are difficult to determine preoperatively. This study aimed to evaluate the usefulness of preoperative 18F-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT) for predicting the malignant potential of GISTs by analyzing the correlation between the maximum standardized uptake value (SUVmax) and postoperative factors. Methods: Thirty consecutive patients underwent surgery after preoperative 18FDG-PET/CT and were diagnosed with pathologically confirmed GIST. The tumor size, mitotic count, MIB-1 index and National Institutes of Health (NIH) risk category were compared with SUVmax. Results: Significant correlations between SUVmax and tumor size and NIH risk category were determined. The sensitivity and specificity of SUVmax for predicting the risk of malignancy were 85.7 and 62.5%, respectively. The optimal cut-off value for SUVmax was 3.0 between patients classified into low-risk and high-risk malignancy groups. There was no significant correlation between SUVmax and mitotic count or MIB-1 index. Multivariate analysis indicated that SUVmax was the only predictive risk factor in the high-risk malignancy group. Conclusions: 18FDG-PET/CT is useful for assessing the malignant potential and bioactivity of GISTs. When SUVmax is >3.0, the tumor must be resected even if it measures <2 cm, because of its high malignant potential.

Performance of F‐18 FDG PET/CT for predicting malignant potential of gastrointestinal stromal tumors: A systematic review and meta‐analysis

“…The remaining nine full‐text articles were assessed for eligibility, and two articles were excluded because of insufficient data for the calculation of sensitivity and specificity of F‐18 FDG PET or PET/CT for the prediction of malignant potential of GISTs. Finally, 10 results from seven studies were selected and were eligible for the systematic review and meta‐analysis, and no additional studies were found screening the references of these articles . The characteristics of the included studies are presented in Table .…”

“…We conducted all analyses based on per‐patient data and/or per‐lesion data analysis. Among those seven studies included in the current review, six studies conducted patient‐based analysis of F‐18 FDG PET/CT . The remaining one study conducted both of patient‐based and lesion‐based analyses .…”

A case of pancreatic schwannoma showing increased FDG uptake on PET/CT

“…Generally, malignant tumors tend to accumulate FDG because of the hypermetabolic nature of malignant cells. Actually, FDG-PET/CT is useful for assessing the malignant potential and bioactivity of gastrointestinal stromal tumors (GISTs) [7]. It has been reported that schwannomas in peripheral nerve sheaths and in the gastrointestinal tract occasionally show increased FDP uptake even though they are benign [8], [9].…”

Subepithelial rectal gastrointestinal stromal tumor – the use of endoscopic ultrasound-guided fine needle aspiration to establish a definitive cytological diagnosis: a case report

“…Other studies found that it provides a timelier and more accurate response assessment compared to a computed tomography (CT) scan and magnetic resonance imaging (MRI) [21]. Moreover, 18 F-FDG PET may provide information about the malignancy: a tumor presenting maximum standardized uptake value (SUV) greater than 3.0 has a high malignant potential even in small tumors (<2 cm) [22]. Therefore, this imaging modality should be considered in all cases of GISTs, especially in metastatic disease, and while monitoring treatment response.…”