Comparison of Outcomes Between Radical Nephrectomy and Partial Nephrectomy in Clinical T2 Renal Cell Carcinoma: A Retrospective Korean Renal Cell Carcinoma Cohort Study

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J Urol Oncol. 2024;22(2):136-143

Publication date (electronic) : 2024 July 31

doi : https://doi.org/10.22465/juo.244800360018

Younsoo Chung¹, Seok-Soo Byun^1,2, Sung Kyu Hong^1,2, Sangchul Lee^1,2, Chang Wook Jeong^2,3, Seok Ho Kang⁴, Sung-Hoo Hong⁵, Ji Youl Lee⁵, Yong-June Kim⁶, Jinsoo Chung⁷, Eu Chang Hwang⁸, Tae Gyun Kwon⁹, Jung Kwon Kim^,10

¹Department of Urology, Seoul National University Bundang Hospital, Seongnam, Korea

²Department of Urology, Seoul National University College of Medicine, Seoul, Korea

³Department of Urology, Seoul National University Hospital, Seoul, Korea

⁴Department of Urology, Korea University Anam Hospital, Seoul, Korea

⁵Department of Urology, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea

⁶Department of Urology, Chungbuk National University Hospital, Cheongju, Korea

⁷Department of Urology, National Cancer Center, Goyang, Korea

⁸Department of Urology, Chonnam National University Medical School, Gwangju, Korea

⁹Department of Urology, Kyungpook National University Chilgok Hospital, Daegu, Korea

¹⁰Department of Urology, Asan Medical Center, Seoul, Korea

Corresponding author: Jung Kwon Kim Department of Urology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 82 Gumi-ro 173beon-gil, Bundang-gu, Seongnam 13620, Korea Email: andss1@hanmail.net

Received 2024 April 30; Revised 2024 June 24; Accepted 2024 July 8.

Abstract

INTRODUCTION

Renal cell carcinoma (RCC) represents 2.2% (n=431,288) of all newly diagnosed cancers, with a mortality rate of 1.8% (n=179,368) according to 2020 GLOBOCAN data [1]. Over the past 2 decades, surgical approaches to RCC have evolved [2]. Compared to radical nephrectomy (RN), partial nephrectomy (PN) has demonstrated benefits in preserving renal function [3,4]. The principle of nephron preservation is thought to play a role in patient prognosis, prompting the increased use of PN [5-9]. Consensus indicates that PN should be the treatment of choice for T1-stage tumors when feasible [2]. However, the optimal approach for T2 tumors is still under debate. Although RN remains the gold standard for tumors of stage T2 or higher, several recent reviews have suggested that PN may represent a viable alternative for T2 tumors [3,10-12].

In South Korea, the Korean Renal Cell Carcinoma (KORCC) registry has been established as a multicenter RCC database [13]. This study aimed to leverage the KORCC database to aid in determining whether to perform PN or RN in patients with stage T2 RCC. By utilizing data from the KORCC registry for clinical T2 (cT2) RCC cases, the study retrospectively compared outcomes between PN and RN.

MATERIALS AND METHODS

The study was conducted in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. The research focused on adult patients with cT2 RCC, identified from 8 tertiary hospitals in the KORCC database between 2003 and 2023. Specifically, patients with a postoperative pathologic confirmation of RCC were included. The exclusion criteria encompassed patients with a solitary kidney, bilateral renal tumors, pathologic stage N1 (pN1), or pathologic stage M1 (pM1). The patient cohort was subsequently divided into PN and RN arms based on the surgical method employed.

RESULTS

A total of 740 patients were included in this study. Prior to PSM, the PN arm comprised 53 patients, while the RN arm included 687 patients. Baseline characteristics before PSM are presented in Supplementary Table 1. The PN arm demonstrated a significantly higher eGFR compared to the RN arm (92.0 mL/min/1.73 m² vs. 77.0 mL/min/1.73 m², p<0.001), along with a significantly lower RENAL nephrometry score (9.0 vs. 10.1, p<0.001). Additionally, the PN arm had a substantially higher percentage of clinical T2a (cT2a) cases (86.3% vs. 73.2%, p=0.041). After PSM, the PN arm consisted of 44 patients, while the RN arm included 132. Baseline characteristics following PSM are detailed in Table 1. Following PSM, no significant differences were noted between the PN and RN arms, with the exception of laterality (68.2% vs. 48.5%, p=0.023) (Table 1).

Table 1.

Baseline characteristics

1. Perioperative Outcomes

Table 2 delineates the perioperative outcomes for each arm. The operative time was longer for the PN arm (169.0 minutes vs. 150.4 minutes, p=0.042). No significant difference was found in the type of operation; however, the use of the robotic method was more prevalent in the PN arm (79.5% vs. 44.7%). The intraoperative complication rate was lower in the PN arm (2.3% vs. 12.9%, p=0.044), whereas the postoperative complication rate was higher in that arm (22.7% vs. 9.8%, p=0.028). Furthermore, complications of Clavien-Dindo classification grade III or higher were significantly more frequent in the PN arm (11.4% vs. 0.08%, p<0.001). Urological complications of Clavien-Dindo classification grade III or higher were also more prevalent among the arm receiving PN (6.8% vs. 0%, p=0.015). Complication rates for open and minimally invasive surgical procedures are available in Supplementary Table 2.

Table 2.

Perioperative and postoperative outcomes

At follow-up, the PN arm displayed significantly better renal function. The incidence of de novo CKD in the sixth postoperative month was 3.1% in the PN compared to 37.6% in the RN arm. This indicates that the incidence in the RN arm was over 12 times higher than that in the PN arm (p<0.001).

2. Pathology

Pathologic outcomes are presented in Table 3. A significant difference was noted in the distribution of pT stages between the 2 arms (p=0.006), with PN displaying a higher proportion of pT1 (45.5% vs. 21.2%). Other microscopic findings, including positive margins (0.0% vs. 0.8%, p>0.999), Fuhrman grade 3/4 (69.8% vs. 77.6%, p=0.302), sarcomatoid differentiation (7.0% vs. 11.3%, p=0.420), necrosis (25.0% vs. 39.3%, p=0.088), lymphovascular invasion (2.3% vs. 6.8%, p=0.259), and capsular invasion (30.2% vs. 37.5%, p=0.389), were not significantly different between the arms.

Table 3.

Pathologic outcomes

3. Oncologic Outcomes

The KM curves revealed no significant differences in OS, CSS, or RFS between the 2 arms (p=0.192, p=0.289, and p=0.471, respectively) (Fig. 1). In the 5-year survival analysis, the RN arm exhibited a 5-year OS rate of 94.4%, compared to a 100% rate in the PN arm. In comparison, the RN arm displayed a 5-year CSS rate of 96.3%, while the PN arm demonstrated a rate of 100%. Regarding RFS, the RN arm had a rate of 80.8%, and the PN arm had a rate of 93.1%.

Fig. 1.

(A) Overall survival Kaplan-Meier curve of radical nephrectomy and partial nephrectomy patients. (B) Cancer-specific survival Kaplan-Meier curve of radical nephrectomy and partial nephrectomy patients. (C) Recurrence-free survival Kaplan-Meier curve of radical nephrectomy and partial nephrectomy patients.

4. Subanalysis

Following Cox regression analysis for OS, no significant risk factors for OS were identified, perhaps due to an insufficient number of events for analysis. The results of the HR analysis for RFS in cT2 RCC are presented in Table 4. Univariable Cox regression analysis revealed significant associations for CRP levels (HR, 1.128; 95% confidence interval [CI], 1.047–1.216), necrosis (HR, 2.572; 95% CI, 1.150–9.688), capsular invasion (HR, 2.674; 95% CI, 1.172– 6.102), and lymphovascular invasion (HR, 5.047; 95% CI, 1.133–22.470). PN did not significantly impact RFS (HR, 0.675; 95% CI, 0.230–1.979). However, in the multivariable Cox regression analysis, CRP levels remained a significant factor (HR, 1.127; 95% CI, 1.045–1.215).

Table 4.

Recurrence-free survival Cox regression study

DISCUSSION

This study compared the outcomes of PN and RN for the treatment of cT2 RCC. Survival analysis using KM curves for OS, CSS, and RFS revealed no significant differences between arms. Subanalysis demonstrated that the use of PN did not significantly influence RFS; however, RFS was significantly associated with CRP levels. Urologic complications, including acute kidney injury and urine leakage, contributed to a greater incidence of Clavien-Dindo classification grade III or higher complications in the PN arm. Urine leakage was classified as a Clavien-Dindo classification grade III complication due to the need for additional intervention, specifically the placement of a ureteral stent. However, the PN arm included only 1 case of de novo CKD at 6 months postoperatively, in contrast to its occurrence in nearly onethird of the patients in the RN arm.

In a systematic review and meta-analysis, Huang et al. [14] revealed that compared to RN, PN—a more technically demanding surgery—necessitates a longer operative time and results in greater intraoperative blood loss. In our study, the operative time was significantly longer for PN than RN; however, EBL did not differ significantly between the arms. Despite the absence of a significant difference in EBL, the higher frequency of complications underscores the technically challenging nature of the procedure.

Several studies have examined survival outcomes for cT2 RCC. Bertolo et al. [15] reported an all-cause mortality rate of 3.3%, a cancer-specific mortality rate of 0.8%, and a recurrence rate of 10% after robot-assisted laparoscopic PN for cT2a RCC. Klett et al. [11] found no significant difference in OS, CSS, or metastasis-free survival between RN and PN. Similarly, a multicenter study by Kopp et al. [16] on cT2 RCC revealed no significant difference in OS, CSS, or progressionfree survival. An investigation of cT2 RCC conducted by Alanee et al. indicated that PN and RN yielded comparable results in terms of CSS [12]. Amparore et al. [17] compared the 5-year survival of cT2 RCC between PN and RN and found no significant difference in all-cause or cancer-specific mortality. However, some research suggests that PN may be associated with superior OS outcomes [18]. After reviewing several studies on cT2 RCC, we conclude that the oncologic outcomes of PN and RN are similar. In our study, KM curves also displayed no significant differences between PN and RN in OS, CSS, or RFS.

The results of this study suggest a lower complication rate than those reported in previous research [15,19-21]. PN carries an inherently higher risk of complications compared to RN because it involves breaching the collecting system, potentially leading to the development of pseudoaneurysms after renorrhaphy. De novo CKD has been shown to occur in approximately half of cases following RN, whereas the incidence after PN is more variable and generally lower [3,22]. In our study, de novo CKD occurred in approximately one-third of the patients after RN, while only 1 case arose following PN. CKD is associated with reduced survival in patients with cancer, as noted by Lee et al. [23].

According to O’Brian et al. [24], elevated CRP levels are indicative of poor prognosis in urological cancers. Hu et al. [25] reported that a higher CRP concentration was associated with comparatively poor OS and CSS in cases of RCC. Additionally, elevated CRP levels have been associated with worse CSS and progression-free survival in patients with localized RCC [25]. Wu et al. [26] found that both OS and CSS were significantly associated with pooled HR, suggesting a connection between increased CRP and reduced survival in RCC. In our study, we confirmed an association between CRP level and RFS.

This study is notable for its utilization of data from multiple tertiary hospitals in Korea. However, the multicenter nature of the data may have introduced variations in the techniques employed for PN. The accuracy of renal function tracking was also compromised by incomplete follow-up data. Additionally, several biases are inherent to the retrospective nature of the study and the reliance on surgical data from tertiary hospitals. The exclusion of pN1 and pM1 cases further restricted the comparison of surgical outcomes in advanced RCC and limited the survival analysis. Preoperatively determining nodal status is challenging, which is another inherent limitation of retrospective study designs. The methods used, such as open surgery, handassisted laparoscopic surgery, pure laparoscopic surgery, and robotic-assisted laparoscopic surgery, are varied and may not reflect current surgical trends. We also attempted a Cox regression analysis for OS, but it did not yield meaningful results, presumably due to an insufficient number of events; thus, it was difficult to analyze the HRs for OS. Finally, the PSM process resulted in the removal of many cases, which likely contributed to the challenges regarding Cox analysis. Nevertheless, the use of PSM to address confounding variables and balance the data is another strength of the present study.

CONCLUSIONS

In cT2 RCC, PN demonstrated a lower incidence of de novo CKD compared to RN, with no significant differences in survival outcomes. These findings suggest that PN could represent a viable alternative to RN for select patients with cT2 RCC, offering comparable survival outcomes while reducing the risk of de novo CKD. Additional research and prospective studies are required to validate these findings in advanced RCC.

Supplementary Materials

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