Diagnostic Accuracy of Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography in Differentiating Tumor and Bland Thrombus in Patients With Cancer: A Systematic Review and Meta‐Analysis

INTRODUCTION: Differentiating tumor thrombus from bland thrombus can be challenging. This study assessed the diagnostic performance of positron emission tomography-computed tomography (PET/CT) scans in differentiating bland versus tumor thrombi in patients with cancer. METHODS: We systematically searched for observational studies evaluating the diagnostic accuracy of PET/CT scans in differentiating tumor from bland thrombi in adult cancer patients. We included patients with suspected tumor or bland thrombus on PET/CT who underwent histopathological evaluation and/or confirmatory imaging or clinical follow-up. Sensitivity and specificity were estimated using a random-effects model. Positive and negative likelihood ratios (LR+ and LR-) and diagnostic odds ratio (DOR) were derived from the pooled estimates. RESULTS: Five studies were included (217 patients; mean age 55.9 years). Hepatobiliary malignancies (49%) and renal tumors (24%) were the most frequent, with the renal vein, portal vein, and inferior vena cava most frequently involved. Maximum standardized uptake value (SUVmax) was significantly higher in malignant compared to bland thrombi, with reported diagnostic cutoffs ranging from 2.25 to 3.63. PET/CT scan showed diagnostic accuracy with pooled sensitivity 92.2%, specificity 94.2%, LR- 0.121, LR+ 10.919, and DOR of 91.770. CONCLUSION: PET/CT scan may be beneficial in distinguishing tumor from bland thrombus in cancer patients.