MP40-19: How to identify patients suitable for conservative management of upper tract urothelial carcinoma (UTUC) according to tumor size: implications for clinical guidelines

Eugenio Ventimiglia*, Christian Corsini, Margherita Fantin, Mario de Angelis, Pietro Dioni, Marco Moschini, Daniele Raggi, Maurilio Ponzoni, Umberto Capitanio, Andrea Necchi, Roberta Lucianò, Milan, Italy, Olivier Traxer, Paris, France, Alberto Briganti, Francesco Montorsi, Luca Villa, Andrea Salonia, Milan, Italy

Introduction: Tumor size < 2cm is the upper dimensional limit for conservative management of upper tract urothelial carcinoma (UTUC). Within this indication, we aimed to analyze the risk of adverse oncological outcomes of this approach according to specific tumor size.

Methods: Data from 151 consecutive ureteroscopies (n=39 patients) performed for UTUC at a single academic center between 2015 and 2021 were included in this analysis. Two experienced endo-urologists performed all the procedures. Ureteroscopies were performed using a digital flexible ureterorenoscope (Flex XC, Karl-Storz). Ureteroscopic biopsy forceps (3 Fr Piranha, Boston Scientific) were used in every case. Biopsy specimens were assessed by a dedicated uro-pathologist according to 2016 WHO grading classification and classified into low- vs high-grade. Tumor Ho:YAG laser ablation was performed in any case whenever feasible (VersaPulse PowerSuite 100W, Lumenis) using 1J and 10 Hz. Tumor size was evaluated at pre-operative contrast-enhanced CT-scan; for non-CT visible lesions, size was endoscopically estimated by comparing with a 0.038” nitinol guidewire. We analysed the association between tumor size and histopathological grade according to different size cut-offs (=1 and <1.5, =1.5, and =2 cm). Moreover, we explored the graphical relationship between tumor size and the multivariable adjusted probability of having high-grade tumor at biopsy (LOWESS curve).

Results: Mean [IQR] tumor size was 1.5 [0.8-2.0] cm. High grade disease was found in 34 cases (23%). At multivariable logistic regression analysis tumor size = 1.5 cm (OR 2.46 [1.06-5.88], p=0.04) and = 2.0 cm (OR 2.90 [1.24-6.93]) were associated to increased risk of having high-grade disease, whereas tumor size between 1 and 1.5 cm was not (p=0.80). We then graphically modelled the multivariable adjusted risk of high-grade disease according to different tumor size cutoffs. The risk of high-grade disease (~ 20%) remained stable for tumors < 1.5 cm, then linearly increased up to 30% for tumors > 2cm.

Conclusions: The probability of diagnosing high-grade UTUC during fURS marginally increases for tumor size = 1.5 cm as compared to smaller lesions. These patients need to be accurately counselled regarding the risk of not being enrollable in conservative management protocols.

Source of Funding: none