Kidney-Sparing Surgery for Upper Tract Urothelial Carcinoma-Modalities, Outcomes, and Limitations.

Upper tract urothelial carcinoma (UTUC) accounts for 5-10% of urothelial cancers and is associated with high morbidity and mortality. Increasing incidence of UTUC has been observed since the 1970's, alongside the evolution of advance imaging techniques, precision biopsy equipment, and risk stratification models. The high morbidity of radical nephroureterectomy (RNU) which is still the gold-standard treatment for high-risk UTUC, has driven the development of kidney-sparing surgery alternatives for low-risk UTUC. Now, several treatment approaches have outcomes comparable to RNU for low-risk UTUC and guidelines are recommending kidney-sparing surgery for favorable low-risk disease. The main categories of kidney-sparing surgery include segmental ureterectomy, endoscopic ablation, chemoablation, and vascular-targeted phototherapy. These treatments are highly nuanced making them difficult to compare, but for most cases of favorable low-grade disease, we recommend endoscopic laser ablation with optional adjuvant intracavitary therapy. Adverse events associated with kidney-sparing surgery include ureteral stricture, bleeding requiring transfusion, and bladder recurrence of UTUC. Limitations of kidney-sparing surgery include appropriate tissue sampling (contributing to under-grading and under-staging), higher rates of ipsilateral recurrence, and potential for grade and stage progression. Collectively, these may subsequently necessitate RNU. Here, we review the technical variations and evidence behind kidney-sparing therapies as well as their practicality in the real world.