Accuracy of High-Frequency Endoluminal Ultrasonography for Clinical Staging of Upper Tract Urothelial Carcinoma

Introduction: Staging of upper tract urothelial carcinoma (UTUC) remains a dilemma due to imaging and biopsy limitations leading to understaging. We seek to determine the accuracy of endoluminal ultrasound (ELUS) for clinical staging of UTUC.

Materials and methods: Patients evaluated for UTUC underwent retrograde pyelography, ureteroscopy, and ELUS. ELUS was performed using mechanical radial scanning at 20 MHz in B-mode with a 5F probe. Cine clips were evaluated by 2 radiologists blinded to ureteroscopic and pathology findings. Results were compared to pathology from nephroureterectomy. Inclusion criteria were patients who underwent nephroureterectomy without pretreatment or managed endoscopically for cTa-1 disease and were without recurrence for >1 year.

Results: From 2008 to 2013, 53 patients underwent ELUS without complication. Twenty-seven patients met inclusion criteria with conclusive ELUS imaging. ELUS accurately identified 16 of 21 patients with non-muscle invasive (MI) disease (18 pTa, 2 pT1, 1 CIS) and 1 of 6 patients with at least MI disease (2 pT2, 4 pT3). For MI disease, the positive predictive value (PPV), negative predictive value, and accuracy was 76.2%, 16.7%, and 63%, respectively, while for non-organ confined (OC) disease results were 0%, 81.8%, and 66.7%, respectively.

Conclusions: With current technique and instrumentation, ELUS may prove useful in select cases to confirm findings of non-MI and OC disease. However, it has insufficient PPV for stage pT2-3 disease. Further studies and better instrumentation are needed before incorporation into clinical practice.