Objective To predict the renal function after nephroureterectomy (NUR) for upper urinary tract urothelial cancer (UTUC) based on preoperative technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) renal scintigraphy. Subjects and methods We retrospectively reviewed 238 patients who originally underwent nephroureterectomy for UTUC between 2007 and 2010. Of these patients, 129 underwent MAG3 renal scintigraphy before unilateral NUR. Serum creatinine was measured in all of the patients before surgery, and renal function was monitored for one year after surgery. Preoperative and postoperative eGFRs were compared and analyzed based on the preoperative MAG3 renal scintigraphy. Results A total of 129 patients, including 62 men (48%) and 67 women (52%) with an average age at surgery of 69.0 years (range from 48 to 87) were included in this study. The mean preoperative creatinine level was 1.42 mg/dL, and the baseline eGFR was 54.76 ml/min/1.73 m2. One year after NUR, the mean creatinine level was 1.89 mg/dL, and the eGFR was 44.44 ml/min/1.73 m2, a mean decrease of 18.73%. The preoperative effective renal plasma flow (ERPF) of the operated kidney was 91.65 ml/min/1.73 m2, and that of the remaining kidney 158.30 ml/ min/1.73 m2. The average preoperative ERPF of the resected kidney accounted for 34% of total preoperative ERPF, which was statistically significant in its relation to the decrease in eGFR. The decrease in eGFR ratio was also significantly correlated with the calculated decrease in ERPF ratio (R2 = 0.279, p < 0.001). The predictive equation of renal function one year after NUR was established as following: eGFR decreased ratio = –0.80 × predictive ERPF decreased ratio +0.72. Conclusion We developed an equation to predict postnephroureterectomy 1 year eGFR before surgery based on preoperative MAG3 renal scintigraphy results and preoperative eGFR. The equation could be more accurate in the situation if the diseased kidney is not hydronephrotic.
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