Antegrade administration of mitomycin gel for upper tract urothelial carcinoma via percutaneous nephrostomy tube: a multi-institutional retrospective cohort study

Objectives: To assess the safety profile of antegrade mitomycin gel instillation through a percutaneous nephrostomy tube (PCNT) for upper tract urothelial carcinoma (UTUC) with the aim of decreasing morbidity associated with therapy. Patients and Methods: Patients undergoing antegrade administration of mitomycin gel via PCNT were retrospectively included for analysis from four tertiary referral centres between 2020 and 2022. The primary outcome was safety profile, as graded by Common Terminology Criteria for Adverse Events (v5.0). Post-therapy disease burden was assessed by primary disease evaluation (PDE) via ureteroscopy. Results: Thirty-two patients received at least one dose of mitomycin gel via PCNT for UTUC, 29 of whom completed induction and underwent PDE. Thirteen patients (41%) had residual tumour present prior to induction therapy. At a median of 15.0 months following first dose of induction therapy, ureteric stenosis occurred in three patients (9%), all of whom were treated without later recurrence or chronic stenosis. Other adverse events included fatigue (27%), flank pain (19%), urinary tract infection (12%), sepsis (8%) and haematuria (8%). No patients had impaired renal function during follow-up and there were no treatment-related deaths. Seventeen patients (59%) had no evidence of disease at PDE and have not experienced recurrence at a median follow-up of 13.0 months post induction. Conclusions: Administration of mitomycin gel via a PCNT offers a low rate of ureteric stenosis, demonstrates a favourable safety profile, and is administered without general anaesthesia.