Predict the residual renal function using preoperative GFR of 99mTc-DTPA dynamic renal images on RCC patients with nephron sparing surgery

1320 Objectives: In previous studies, some researchers have tried to predict the post-operation residual renal function using the proportion of tumors in homolateral renal volume on dynamic renal imaging.Based on some inconsistent clinical cases, we aimed to explore the relationship between the tumor size and renal function of the patients who underwent nephron sparing surgery. Methods: In this retrospective study, 79 patients (include 30 cortex invasion, 39 medulla invasion and 10 renal sinus invasion, age: 56.6 ± 11.2 years) with renal tumor nephron sparing surgery during December 2016 to November 2018 were collected. According to the tumor size, the patients were divided into three groups (group A: <30 mm; group B: ≥30 and <50 mm; group C: ≥50 mm). There was no significant difference in gender, age, BMI, tumor position of kidney, history of hypertension and diabetes between three groups (Table 1). All patients underwent both 99mTc-DTPA renal dynamic scans and double sample methods to gain GFR (gGFR and tGFR, respectively) before the operation. 22 patients had another renal dynamic scan within 1 month after surgery. The clinical parameters, such as: operative time, urea nitrogen (BUN) and creatinine (Cr), of pre- and post-operative, were recorded. And the age, body weight and postoperative creatinine value were used for the calculation of the creatinine clearance rate (Ccr). Results: (1) Among three groups, no significant difference was observed in pre- and post-operative Ccr (P>0.05); (2) Compared with the preoperative affected renal function, postoperative residual renal function (GFR) has lightly decreased, but the changes were not significant (P>0.05). (3) There was no significant difference in the gGFR and tGFR of the three groups (P>0.05). Conclusions: In patients with renal tumor, with the increase of tumor size, the level of pre- and post-operative Ccr, GFR of affected kidney, gGFR and tGFR didn’t decrease significantly. we concluded that the tumor size has no effect on the renal function of patients with renal tumor. Considering the tumor has no normal glomerular structure, the affected renal function of pre-operation from 99mTc-DTPA dynamic renal images can be used to reflect the postoperative residual renal function. Key words: Residual renal function; Nephron sparing surgery; 99mTc-DTPA dynamic renal images; Tumor size