Supplementary Material for: Real-world insights: Balancing diagnostic benefits and oncological risks of ureteroscopic biopsy before radical nephroureterectomy for upper tract urothelial carcinoma

Purpose:

The role of diagnostic ureteroscopy (URS) prior to radical nephroureterectomy (RNU) remains controversial due to concerns about an increased risk of intravesical recurrence. However, existing studies frequently exhibit two major confounders: lack of reporting on the use of mitomycin C instillation after RNU and not excluding patients with a history of bladder cancer.

Methods:

We retrospectively evaluated the proportion of RNU patients for whom the URS biopsy result before RNU was decisive for therapy. The impact of URS biopsy on intravesical recurrence (IVR), overall survival (OS), and cancer-specific survival (CSS) was evaluated using univariate and multivariable Cox regression analyses and Kaplan-Meier curves.

Results:

Between January 2005 and November 2022, 229 patients with upper tract urothelial carcinoma (UTUC) underwent RNU with single post-operative mitomycin C instillation at our department. After excluding those with a history of bladder cancer, 148 RNU patients were included in the final analysis (prior URS biopsy: 125 (84%), no URS biopsy: 23 (16%)). Before RNU, both urine cytology and CT were inconclusive in 37% of patients. URS biopsy confirmed UTUC in 73% of these cases. Univariate and multivariable Cox regression analyses revealed no significant differences in IVR, OS, or CSS between patients who underwent URS biopsy before RNU and those who did not.

Conclusion:

URS biopsy was essential for clinical decision-making in one-third of patients who underwent RNU. There were no oncologic disadvantages for patients who underwent URS biopsy prior to RNU, demonstrating its utility in clinical practice without compromising oncologic outcomes.