Comparative Analysis of Long-Term Renal Outcomes in Upper Tract Urothelial Carcinoma: Local Ablation Versus Radical Nephroureterectomy.

(1) Background: Upper tract urothelial carcinoma (UTUC) is typically managed through radical nephroureterectomy (RNU) or local ablation (LA). Compared to RNU, LA offers nephron-sparing benefit for select patients but may present increased recurrence risk. This study primarily compares long-term differences between LA and RNU in chronic kidney disease (CKD) progression, estimated glomerular filtration rate (eGFR) decline, all-cause mortality, and need for dialysis. (2) Methods: A retrospective cohort study was conducted using the TriNetX database, examining patients with UTUC treated with RNU (n = 2007) or LA (n = 4172). Propensity score matching balanced both cohorts (n = 1965 per group). Risk ratios and hazard ratios with 95% confidence intervals were calculated over 10 years. (3) Results: At 10 years, LA preserved higher mean eGFR (53.49 vs. 46.72; p < 0.001) and lower mean creatinine (1.56 vs. 1.66; p = 0.017). However, LA held a higher incidence of end-stage renal disease (ESRD) (3.6% vs. 2.2%, p = 0.008) and all-cause mortality (26.7% vs. 23.5%, p = 0.016). There was no significant difference in rates of dialysis (p = 0.79). (4) Conclusions: RNU did not carry an increased risk of ESRD, advanced stages of CKD, need for renal dialysis, or overall mortality compared with LA. LA may delay but not totally prevent renal dysfunction when compared to RNU, and exhibits a more gradual timeline.