Equation Predicts Renal Function after Nephroureterectomy to Treat Upper Tract Urothelial Carcinoma.

PURPOSE: A preoperative tool is warranted to predict renal function after radical nephroureterectomy, as this would optimize treatment plans and avoid postoperative end-stage renal disease. Therefore, this study aimed to develop an equation to predict postoperative renal function changes.

MATERIALS AND METHODS: We reviewed the medical records of 487 patients who were diagnosed with upper tract urothelial carcinoma treated by unilateral radical nephroureterectomy with bladder cuff excision between 2010 and 2020. Renal function was comprehensively evaluated preoperatively using 99mTc-mercaptoacetyltriglycine renal scintigraphy. Serum creatinine was evaluated before, and 3 and 6 months postoperatively. We then developed a predictive equation using Pearson linear correlation analysis.

RESULTS: The median preoperative effective renal plasma flow was 241.30 mL/min., of which the lesion side accounted for 35.6% of the total. A predictive equation for changes in postoperative renal function was established. The preoperative lesion-side effective renal plasma flow ratio was significantly associated with an estimated glomerular filtration rate (eGFR) decline ratio at 3 months postoperatively (r = 0.613, P <0.001). Internal validation of the patients during 2021 confirmed that the equation could predict eGFR decline (r = 0.896) and radical nephroureterectomy-related cisplatin ineligibility (100%) at 3 months postoperatively.

CONCLUSIONS: We established an equation that assists in predicting changes in postoperative eGFRs based on the preoperative lesion-side effective renal plasma flow ratio. This equation can also predict postoperative residual renal function.