Correlation Between Confocal Laser Endomicroscopy (Cellvizio®) and Histological Grading of Upper Tract Urothelial Carcinoma: A Step Forward for a Better Selection of Patients Suitable for Conservative Management

Abstract

Background: Despite the recent growing interest in the conservative management of upper tract urothelial carcinoma (UTUC), the diagnostic process is still a challenge for the risk of tumor undergrading. Real-time confocal laser endomicroscopy (CLE) provides in vivo microscopic images of tissues using a low-energy laser light source.

Objective: To describe our initial experience with CLE for the real-time characterization of UTUC.

Design, setting, and participants: Fourteen flexible ureteroscopies (f-URS) were performed at our center with CLE for UTUC. Lesions were preoperatively identified at computed tomography-intravenous urography. Cellvizio system was used during f-URS to perform CLE on the targeted lesions. Biopsies were then performed.

Intervention: f-URS with CLE.

Outcome measurements and statistical analysis: Surgeon's CLE readings (low-grade/high-grade/carcinoma in situ [CIS]) were documented in the operation notes. A dedicated genitourinary pathologist-blinded to the surgeon reading-examined all specimens. A third person collected prospectively the CLE readings and the histopathological reports. Cohen's Kappa analysis was performed to test interobserver agreement.

Results and limitations: The mean diameter of tumors at computed tomography scan was 26mm (range, 5-50mm). In eight patients, CLE allowed to obtain images compatible with low-grade UTUC, in five patients with high-grade UTUC, and in one case with CIS. We found correspondence between the CLE images and the final histopathological results in seven out of seven cases of low-grade UTUC (100%), in five out of six cases of high-grade UTUC (83%), and in one out of one case of CIS (100%). Substantial agreement was found at interobserver agreement (k=0.64) between CLE and histological reading. No complications and/or limitations related to the use of CLE were recorded.

Conclusions: CLE is a promising new technology in providing a reliable real-time histological characterization of UTUC lesions. Ideal targets might be UTUC patients potentially candidates for conservative management.

Patient summary: We believe that a conservative treatment for low-grade upper tract urothelial carcinoma is an option that must be considered. The diagnostic process is still lacking of accurate tools. In this study, we find that confocal laser endomicroscopy, using the Cellvizio system, seems to help the clinician to have a real-time histological characterization of upper tract urothelial carcinoma lesions. This could better select patients for a conservative treatment.

Keywords: Confocal laser endomicroscopy; Flexible ureteroscopy; Upper tract urothelial carcinoma.