PD58-06: Antegrade Administration of Reverse Thermal Mitomycin Gel for Primary Chemoablation of Upper Tract Urothelial Carcinoma via Percutaneous Nephrostomy Tube: a Multi-Institutional Real-World Experience

Kyle Rose*, Tampa, FL, Gopal Narang, Scottsdale, AZ, Geoffrey Rosen, Columbia, MO, Craig Labbate, Houston, TX, Justin Campagna, Scottsdale, AZ, Alice Yu, Brandon Manley, Phillipe Spiess, Roger Li, Tampa, FL, Mehrad Adibi, Houston, TX, Katie Murray, Columbia, MO, Wade Sexton, Tampa, FL, Mitchell Humphreys, Scottsdale, AZ

Introduction: Reverse thermal mitomycin gel (MG) is approved for treatment of low-grade upper tract urothelial carcinoma (UTUC). In the pivotal OLYMPUS trial, repeated retrograde instrumentation of the upper urinary tract under general anesthesia was required for drug instillation. This increased the cost and morbidity associated with therapy and may have contributed to the 44% incidence of ureteral stenosis, and 14% rate of therapy discontinuation. We sought to assess the safety profile and effectiveness of MG instillation through a percutaneous nephrostomy tube, with aims to decrease complications and morbidity with chemoablation.

Methods: After IRB approval, patients who underwent MG therapy for UTUC via a percutaneous nephrostomy tube at multiple institutions were pooled and analyzed for patient demographics, response to therapy, and recurrence patterns. Patients underwent induction therapy which included six installations of once-weekly MG. Primary disease evaluation (PDE) included ureteroscopy post-induction therapy to assess treatment response. The primary outcome was safety profile including complications following antegrade administration, and the secondary outcome was complete response (CR) rate at the time of PDE.

Results: Twenty-six patients received induction therapy with MG via percutaneous nephrostomy tube, 6 (23%) of whom had solitary kidneys. Nine (35%) patients went on to receive at least one dose of maintenance therapy. Ureteral stenosis occurred in 4 (15%) patients. Other adverse events included fatigue (27%), flank pain (19%), UTI (12%), sepsis (8%), and hematuria (8%). No patients had impaired renal function during follow up and no deaths occurred. Thirteen patients (50%) exhibited a CR at post-induction ureteroscopy, while 12 (46%) had a partial response. One patient experienced progression to invasive disease and required a nephroureterectomy. At a median follow up of 7 months (IQR 3-9) post-induction, no patients who experienced a CR recurred.

Conclusions: Antegrade administration of MG via percutaneous nephrostomy tube offers similar efficacy with a lower rate of ureteric stenosis compared to a retrograde approach. In addition to the lower morbidity profile, percutaneous administration allowed for chemoablation without the use of general anesthesia. Antegrade administration of MG is efficacious, safe and should be considered in patients who are not otherwise candidates for, or defer, immediate radical nephroureterectomy.

Source of Funding: none