Evaluating ¹⁸F-FDG PET-CT for Regional Lymph Node Assessment in Advanced Upper Tract Urothelial Carcinoma

Preoperative lymph node staging in upper tract urothelial carcinoma (UTUC) using ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography combined with computed tomography (PET-CT) is sparsely reported.

This study investigates the diagnostic accuracy of PET-CT and conventional computed tomography (CT) for detecting regional lymph node metastases in patients with UTUC, using histopathology as the reference standard.

A total of 75 consecutive patients with UTUC, who underwent radical nephroureterectomy (RNU) with regional lymphadenectomy (rLAE) between 2014 and 2024, were retrospectively analyzed. All patients underwent preoperative PET-CT.

Accuracy for PET-CT and CT was compared with histopathology in fractionated lymphadenectomy specimens in the total cohort and in the subgroup that did not receive preoperative chemotherapy (PC).

Of the 75 patients, 48 were male (64%), 23 (31%) received PC, and 18 (24%) had histologically confirmed lymph node metastases. For all patients, results for PET-CT and their 95% confidence intervals were as follows: sensitivity 83% (59-96), specificity 70% (57-82), and positive likelihood ratio (LR+) 2.8 (1.8-4.4), compared with 39% (17-64), 83% (70-91), and 2.2 (1.0-5.0) for CT, respectively. In the subgroup of 52 patients who did not receive PC, PET-CT showed a sensitivity of 75% (43-95), specificity of 90% (76-97), and LR+ of 7.5 (2.8-20.1), while CT yielded 25% (6-57), 93% (80-98), and 3.3 (0.8-14.4), respectively. The primary limitation of the study is the limited sample size, particularly the small number of patients with confirmed nodal metastases.

Preoperative PET-CT demonstrates promising diagnostic accuracy for regional lymph node staging in patients with UTUC.