CU 36. Partial nephrectomy and its efficacy

Radical nephrectomy (RN), firstly described by Robson et al. in 1963, had been taken as the standard operation for renal cancer for a long time. However, as the development of imagery, lots of tumors are still small without metastasis or invasion, besides, 15-25% of renal tumors are benign, so it is somewhat illogical to remove the entire kidney due to a tiny tumor. As surgery technology progresses, nephron-sparing surgery (NSS) is more suitable for treatment of small-volume tumors than RN.

Partial nephrectomy (PN) was reported by Czerny in 1887, the indication of which was dertermined by Vermooten et al. in 1950. The purpose of NSS is to completely remove the tumor but retain normal kidney tissues as more as possible. This study combines 10 years of researchers' clinical experience, reviews the NSS and PN literatures of the past decade in detail, achieves that partial nephrectomy is safe and effective for small-volume tumors, and it is also suitable for central type tumors and tumors greater than 7 cm.

From 2000 and 2011, we mainly performed four kinds of surgical procedures for renal tumors: between 2000 and 2005, we mainly use the RN approach; after 2005, we carried out partial nephrectomy, renal tumor enucleation and laparoscopic partial nephrectomy (LPN). Combining with literature data, we analyze surgical technique and efficacy as follows:

In 2010, Li et al. reported 389 cases with T1aN0M0 tumors smaller than 4 cm, the surgical approaches to whom included RN, 1 cm-NSS and mm-NSS. 1 cm-NSS refers to tumor and normal renal tissues in total at an average of 12 mm (10-15 mm); mm- NSS refers to tumor margin is 2.2 mm away from the normal kidney tissue (0-5 mm). In mm-NSS group, 2 cases had in situ relapse. 5-year survival rates in the three groups were 100%, 100% and 98.7%, respectively. It was considered that mm-NSS and 1 cm-NSS, RN are safe and effective in treating tumors smaller than 4 cm. Similarly, Korean scholars also agree that PN and RN had similar effect on pT1b RCC. Another study analyzed effects on 417 LPNs cases and 345 OPNs cases, showing that the 5-year local tumor-free rates were 96% and 94%, respectively (P=0.8). In addition, the small tumors are divided into exogenous, endogenous and central types according to according to their growth pattern, which affects their surgical approaches.

But no matter how the surgical approach is performed, the basic surgical procedures include exposure of renal pedicle, blockage of the renal pedicle vessel and tumor resection. Park et al. described the suture approaches for tumors in detail: absorbable suture 4-0 for vessels and collecting systems, absorbable suture 3-0 for medulla, 2-0 absorbable suture for renal cortex, Teflon strip (0.9 cm × 0.9 cm) and Hem-O-Lok clip were also used for renal cortex suture.

As surgical techniques develop, partial nephrectomy is also performed in those with renal tumors larger than 4 cm but smaller than 7 cm with a 5-year tumor-free survival at 92% and 10-year tumor-free survival at 88%. Factors affecting the patient survival include tumors larger than 7 cm (P=0.002), pathological stage (P=0.001) and Fuhrman grade; multivariate analysis involves pathologic stage (P<0.0001) and Fuhrman grade (P<0.007).

Conclusions: Partial nephrectomy includes open partial nephrectomy, such as 1 cm-NSS and mm-NSS; LPN; robotassisted partial nephrectomy. For those tumors smaller than 4 cm, there is no significant difference on 5-year survival in open surgery and laparoscopic surgery; however, there are more in situ relapses in laparoscopic surgery cases, which may be related to intraoperative injury to false envelope of renal tumors. In this study, we used renal tumor enucleation, which significantly decreases local tumor recurrence and improves surgery efficacy.