Modified dual time point 18F-fluorodeoxyglucose Positron Emission Tomography with Computed Tomography for Lymph Node Staging in Patients with Upper Tract Urothelial Carcinoma
Yu‐Hsiang Yang 1、Ching-Chu Lu2、Ruoh Fang Yen 2、Chao-Yuan Huang1、Jian-Hua Hong1,3
1Department of Urology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, 2 Department of Nuclear Medicine, National Taiwan University Hospital,3Taiwan Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
Purpose: To determine the diagnostic accuracy of 18F-FDG-PET/CT and modified dual time point (early phase and delay phase) FDG-PET/CT for LN detection in patients with upper tract urothelial carcinoma (UTUC) .
Patient and methods: Data of 108 patients with UTUC who underwent dual time point PET/CT followed by surgical treatment in NTUH between 2012 and 2017 were prospectively collected. FDG-PET/CT results were compared with histopathology after lymph node dissection (LND). Recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were analyzed using Kaplan-Meier estimates, and compared for patients with and without suspicious LNs on FDG-PET/CT. The dual-time-point maximum standardized uptake value (SUVmax) and the percent change of SUVmax (ΔSUV max) were measured, respectively. The optimal differential parameter was determined by receiver-operating characteristic curve analysis and evaluation of diagnostic accuracy.
Results: We included 108 patients, of whom 82 underwent LND. Seventeen patients had LN metastasis confirmed at histopathological evaluation. Sensitivity and specificity of FDG-PET/CT for LN detection were 100% (95% confidence interval [CI]: 54–100) and 84% (95% CI: 63-95), respectively. On FDG-PET/CT scan, RFS and CSS were significantly worse in patients with LN-positive than in those with LN-negative (p = 0.03, p = 0.11, respectively) but showed similar OS between the two groups. ΔSUV was able to predict lymph node metastasis in patients with UTUC with acceptable AUC(0.83).
Conclusions: FDG-PET/CT has 100% sensitivity and 84% specificity for LN detection in patients with UTUC. Presence of suspicious LNs on FDG-PET/CT was associated with worse RFS and CSS. In our series, the modified dual-time-point 18F-FDG PET/CT provided a more convenient protocol, improved the diagnostic accuracy to differentiate LN metastasis, and help patient selection for LN dissection. Larger studies are needed for further validation.