San Antonio, Texas USA (UroToday.com) In patients presenting with localized renal cell carcinoma (RCC) 25% will have pre-existing chronic kidney disease (CKD) even in the presence of a normal serum creatinine level. In addition, 20% of patients undergoing nephron-sparing surgery will developed significant CKD within 5 years of surgery. It is well known that decreasing GFR has been correlated with risk of death, cardiovascular events and hospitalization.
In this session, Dr. Dipen Parekh (University of Miami) discussed modifiable factors that may impact the development of CKD in patient’s presenting with localized RCC. The pre-operative evaluation of these patients is crucial in the stratification of patients at high risk of developing significant CKD following renal surgery. Import factors in the pre-operative evaluation include proteinuria, hypertension, hyperlipidemia, and reduce GFR. Identifying patients at high risk of developing significant CKD should be then be considered from nephron-sparing surgery (NSS) and early referral to nephrology as early referral to nephrology has been associated with improvement in overall survival in patients with diabetes showing evidence of CKD.
In regards the surgical technique surgeons have the ability to control the percentage of volume parenchyma spared and the ischemia time during a nephron-sparing procedure. In a study by Campbell and colleagues (Mir et al, Urology 2013), assessing prediction factors of CKD in patient with solitary rental units showed that percentage of renal preservation as the most important factors in the developed of significant CKD. The study was validated in collaboration with the Mayo clinic (Thompson et al, Urology 2012) in which warm ischemia time (WIT) was added to the multivariate analysis model showing that percentage of parenchyma spared was the only predictor associated with development of CKD.
The speaker further focuses on the effect of WIT on renal dysfunction by reviewing historical and contemporary studies on the matter. The first mention of the effect of ischemia on renal damage was presented by Dr. Novick in the 1980’s concluding that ischemia can be sustained with eventual recovery of renal function if ischemia is limited to 30 minutes. The speaker then presents a counter argument with a contemporary prospective randomized trial assessing the effect of ischemia on functional biomarkers, structural biomarkers and electron microscopy structural changes during nephron sparing surgery (NSS). The study looked at serum samples and core biopsies of normal renal parenchyma prior, at 10 minutes intervals and following renal ischemia during NSS. The study showed no difference in serum marker (Creatinine, Cystatin-C and eGFR) between patients with WIT < 30 min compared to those with WIT up to 60 minutes. There was also no difference in structural biomarkers on immunohistochemical analysis looking at several markers of cell integrity (Actin, Integrin, pTyr). In regards to intracellular changes there was significant difference in mitochondria swelling as time of ischemia increased; however, all the changes were reversed 5 minutes after reperfusion.
The speaker concludes pre-screening of patients at risk of developing significant CKD is of most importance to identify patients in which maximal parenchymal preservation should be performed. In regards to ischemia, it appears to be safer than previously though and should not be a limiting factor in regards to providing patients with the best oncological control, parenchymal preservation and renal reconstruction.
Presented By: Dipen J. Parekh, MD, University of Miami Miller School of Medicine
Written By: Andres F. Correa, MD, Society of Urologic Oncology Fellow, Fox Chase Cancer Center
17th Annual Meeting of the Society of Urologic Oncology - November 30 -December 2, 2016 – San Antonio, Texas USA