Volumetry may predict early renal function after nephron sparing surgery in solitary kidney patients

Abstract

We investigate the impact of the residual kidney volume measured by tumor volumetry on preoperative imaging in predicting post-operative renal function. Nephron sparing surgery (NSS) in renal cell carcinoma (RCC) is the standard treatment for T1 kidney tumors. Resection of kidney tumors in solidary kidneys needs precise preoperative counseling of patients regarding post-operative renal function. Patients planned for renal tumor surgery who underwent prior nephrectomy on the contralateral side were included. We identified 35 patients in our database that underwent NSS in solitary kidneys and met the inclusion criteria. Tumor volumetry was performed on computer tomography (CT) or magnetic resonance imaging (MRI) with the Medical Imaging Interaction Toolkit (MITK). Clinical and pathological data were assessed. Follow-up data included renal function over 3 years. Mean age was 64 ± 8.1 years. Mean tumor volume on imaging was 27.5 ± 48.6 cc. Mean kidney volume was 195.2 ± 62.8 cc and mean residual kidney volume was 173.4 ± 65.3 cc. We found a correlation between renal function (MDRD) and residual kidney volume on imaging 1-week post-surgery (p = 0.038). Mid- and long-term renal function was not associated with residual kidney volume. In conclusion, renal volumetry may predict early renal function after NSS.

Keywords: Nephron sparing surgery; Renal cell cancer; Renal function; Solitary kidney; Tumor volume.

Figure 1

Tumor (red circle) and kidney (blue circle) are contoured and the volume is calculated.

Figure 2

Regression analyses of the renal function (MDRD) and the residual kidney volume on imaging 1-week post-surgery. Patients with pre-operative GFR ≥ 45 and < 45 ml/min are shown in blue and red, respectively.