BERKELEY, CA (UroToday.com) - Partial nephrectomy (PN) has emerged as the reference standard for the treatment of small renal cell carcinomas (RCCs), with equivalent oncological outcomes and better preservation of renal function than radical nephrectomy (RN). Furthermore, nephron-sparing surgery (NSS) is imperatively indicated for those who need to optimize postoperative renal function, such as those with tumors in a functional or anatomical solitary kidney. However, PN for solitary kidneys is still a challenging technique in terms of the risk of postoperative hemodialysis. In particular, the validity of laparoscopic PN for the solitary kidney has not been established. Although radiofrequency ablation and cryoablation are considered as treatment options, PN remains the standard procedure for NSS. In this article, we reported short-term functional and oncological outcomes of patients who underwent open and laparoscopic PN for RCC in a solitary kidney.
The median reduction rate of estimated glomerular filtration rates (eGFR) at 3 months after PN was 20.9 %. Three patients who preoperatively had stage 4 chronic kidney disease (CKD) needed temporary hemodialysis after PN. Fifteen patients (93.8 %) developed postoperative acute kidney injury (AKI) with stage 1 in 5 patients, stage 2 in 6 patients, and stage 3 in 4 patients. Risk factors for developing AKI stage 3 were total ischemic time and preoperative eGFR (P = 0.02 and P = 0.004, respectively). All patients whose preoperative eGFR was less than 30 mL/min developed AKI stage 3 postoperatively. Only one patient needed chronic hemodialysis at 8 months after operation. Negative surgical margins were achieved in all patients including the one with pathological T4 disease. No patient showed local or systemic recurrence of the disease during the follow-up period and all patients survived at the final day of observation.
The short-term oncological outcome was the same as, or more acceptable than, for elective PN in a previous report from our institution. The 10-mm margin of normal renal tissue may have provided a favorable oncological outcome in our series. On the other hand, a decrease in the surgical margin might preserve functional renal volume, which leads to better postoperative renal function. Further investigation is needed to determine the appropriate surgical margin to achieve the best outcome for both cancer control and renal function. The median decrease rate of eGFR at 3 months after PN in our study was similar to the other major reports. Preoperative renal function may contribute more strongly to progression to required temporary hemodialysis. In recent years, some investigators have reported that alternative NSS techniques, such as radiofrequency ablation and laparoscopic cryoablation, had protective effects on renal function compared to standard PN in solitary kidneys. These treatments can also be considered to prevent postoperative development of acute kidney injury in selected cases with CKD stage 4.
Our results suggest that PN is a feasible and safe treatment for RCC in a solitary kidney. However this study was a retrospective design and short-term follow period. Thus, further prospective multicenter studies are needed to clarify the long-term renal function and oncological safety of PN for RCC in an anatomically or functionally solitary kidney.
Takeshi Maehana, MD, and Toshiaki Tanaka, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Urology
Sapporo Medical University School of Medicine
South 1 West 16, Chuo-Ku, Sapporo, Hokkaido, 060-8543, JAPAN