Diagnostic Value of ¹⁸F-fluorodeoxyglucose Positron Emission Tomography with Computed Tomography for Lymph Node Staging in Patients with Upper Tract Urothelial Carcinoma

Background: Presence of lymph node metastases (LNM) is an important prognostic factor for cancer-specific survival (CSS) in patients with upper tract urothelial carcinoma (UTUC). In various neoplasms, ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT) is an established modality for preoperative lymph node (LN) staging. In UTUC, the diagnostic value of FDG-PET/CT for LN staging is unknown.

Objective: To determine the diagnostic value of FDG-PET/CT for LN staging in patients with UTUC.

Design, setting, and participants: Data of 152 patients with UTUC who underwent FDG-PET/CT followed by surgical treatment in eight centers between 2007 and 2017 were retrospectively collected. Patients receiving neoadjuvant chemotherapy were excluded.

Outcome measurements and statistical analysis: FDG-PET/CT results were compared with histopathology after lymph node dissection (LND). Recurrence-free survival (RFS), CSS, and overall survival (OS) were analyzed using Kaplan-Meier estimates, and compared for patients with and without suspicious LNs on FDG-PET/CT.

Results and limitations: We included 117 patients, of whom 62 underwent LND. Seventeen patients had LNM at histopathological evaluation. Sensitivity and specificity of FDG-PET/CT for diagnosis of LNM were 82% (95% confidence interval [CI]: 57-96) and 84% (95% CI: 71-94), respectively. RFS was significantly worse in patients with LN-positive FDG-PET/CT than in those with LN-negative FDG-PET/CT (p=0.03). CSS (p=0.11) and OS (p=0.5) were similar between groups. This study is limited by its retrospective design and by its sample size. Our results warrant further validation.

Conclusions: FDG-PET/CT has 82% sensitivity and 84% specificity for the detection of LNM in patients with UTUC. Presence of suspicious LNs on FDG-PET/CT is associated with worse RFS.

Patient summary: In patients with upper tract urothelial cancer, positron emission tomography with computed tomography (PET/CT) scans can detect lymph node metastases with noteworthy accuracy. Presence of suspicious lymph nodes on ¹⁸F-fluorodeoxyglucose PET/CT is associated with worse recurrence-free survival.