Comparison of robot-assisted partial nephrectomy with KangDuo surgical system vs. the da Vinci Si system: Quality of life and medium-term oncological outcomes

To the Editor: Renal cell carcinoma is the most common cancer of the genitourinary tract and leads to over 170,000 deaths annually worldwide. For localized tumors, robot-assisted partial nephrectomy (RAPN) has emerged as a popular option due to its numerous benefits, including better ergonomics, better functional outcomes, similar oncological outcomes, and minimal invasiveness. The KangDuo surgical robot (KD-SR), a novel robotic surgical platform, was developed by SuZhou KangDuo Robot Co., Ltd. (Suzhou, China). Recently, we reported that the KD-SR achieved noninferior outcomes compared to the da Vinci Si Surgical System (DV-SS-Si) in terms of surgical success for T1a tumors.[1] However, the oncological outcomes of the KD-SR and the DV-SS-Si are yet to be compared. In this prospective randomized cohort trial, we aimed to compare the patient-reported health-related quality of life (HRQoL) and medium-term oncological outcomes of the KD-SR vs. the DV-SS-Si for RAPN. This study was based on a double-center randomized controlled study conducted from September 2020 to March 2021 in Peking University First Hospital and Peking Union Medical College Hospital.[1] It is registered at www.chictr.org.cn (ChiCTR2100045983). Patients aged 18–75 years with a suspicion of T1aN0M0 renal cancer (R.E.N.A.L. Nephrometry Score ≤9) were included. The exclusion criteria were pregnancy and contraindication for anesthesia. The trial group accepted RAPN with KD-SR (KD-SR group), while the control group accepted RAPN with DV-SS-Si (DV-SS-Si group). The basic surgical procedures were similar to those published previously.[1] After the preparation of the renal hilum and exposure of the tumor, bulldog clips were introduced for renal hilar clamping. The tumor was completely resected approximately 0.5 cm from the edge of the tumor and the resulting renal wound was closed with running sutures. The bulldog clamps were removed after adequate hemostasis. All surgeries were performed by expert surgeons with experience of >100 standard robotic surgical procedures. In Peking University First Hospital, 60 patients were enrolled, and we further prospectively collected their HRQoL data and oncological outcomes here. Patients who did not receive allocated intervention or those without follow-up information were excluded [Figure 1A]. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines.Figure 1: The study design and the performance of HRQoL. (A) Diagram of study enrollment and final analysis cohort; (B) HRQoL data before treatment and the score changes at 3 months postoperatively in mean ± SD or median (Q1, Q3); (C) HRQoL comparison before treatment and at 3 months postoperatively in the KD-SR and DV-SS-Si groups. The global health status and functional domains comparison between KD-SR and DV-SS-Si (1) before treatment and (2) at 3 months postoperatively; the global health status and functional domains comparison for before treatment and at 3 months postoperatively in (3) KD-SR and (4) DV-SS-Si; HRQoL symptom domains comparison between KD-SR and DV-SS-Si (5) before treatment and (6) at 3 months postoperatively; Symptom domains comparison for before treatment and at 3 months postoperatively in (7) KD-SR and (8) DV-SS-Si. Significance of difference was tested using the Mann–Whitney U for (1), (2), (5), (6), and Wilcoxon-test for (3), (4), (7), (8). Only P-values <0.05 are shown. *Significance of difference was tested using the Mann–Whitney U test. †Significance of difference was tested using the independent samples t-test. DV-SS-Si: da Vinci Si surgical system; HRQoL: Health-related quality of life; KD-SR: KangDuo surgical robot; SD: Standard deviation.HRQoL was measured by the European Organization for the Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30), which was administered 1 day before surgery and 3 months after surgery. The primary endpoints were longitudinal changes in the HRQoL and medium-term oncological outcomes evaluated after at least 2 years. The QLQ-C30 contains 30 items and across the following subscales: one global health status, five functioning scales, and eight symptom scales. The financial impact of cancer was not analyzed herein. Scores were calculated according to the EORTC scoring manual, with all scale scores ranging from 0 to 100. A high score indicated a high level of functioning on the functional scale, but greater severity on the symptom scale. Fisher’s exact test, continuity-correction, or Pearson’s chi-squared test was used for categorical variables, while the independent samples t-test or Mann–Whitney U test was used for continuous variables. All the statistical analyses were performed using the Statistical Package for the Social Sciences (IBM Corp. IBM SPSS Statistics for Windows, Version 29.0.2.0, Armonk, NY), and a P value of <0.05 was considered significant. Among the 60 patients, a 77-year-old woman in good physical condition was also enrolled. In total, 29 patients were allocated to the KD-SR group and 31 to the DV-SS-Si group. One patient (1.7%) assigned to the KD-SR group did not undergo RAPN due to unsatisfactory sterilization of the surgical instruments. Three patients (5.0%) did not complete out the questionnaire as required in the DV-SS-Si group. Therefore, 28 patients in the KD-SR group and 28 patients in the DV-SS-Si group with complete HRQoL reports were included. All 60 patients were successfully contacted to evaluate oncological outcomes. As shown in Supplementary Table 1 and 2, https://links.lww.com/CM9/C118, clinical characteristics were similar between the two groups except for the operative time (112.50 [94.25–143.75] vs. 89.00 [77.00–103.75], U = 154.000, P <0.001). In the comparison of learning curves, the improvement of KD-SR was not obvious, which may be related to the limited cases [Supplementary Figure 1, https://links.lww.com/CM9/C118]. Additionally, our data illustrated that there was no significant difference in the postoperative exhaustion time or the postoperative activity of daily living (ADL) score at 24 h. The majority of postoperative pathological results were revealed as clear renal cell carcinoma in both groups. The baseline HRQoL data were similar between the two groups (P >0.05), and no significant impairment was found in any of the domains after 3 months. At 3 months after RAPN, significant improvements in several domains, including physical functioning, role functioning, social functioning and pain, insomnia, appetite loss, and constipation and diarrhea alleviation, were reported in the KD-SR group [Figure 1B, C]. Similar results were also found in the DV-SS-Si group. In addition, no significant difference was found in the score changes between the two groups. During follow-up, 1 patient (4%) reported recurrence after 1 year and 3 months, and another patient (4%) reported bone metastasis 1 year postoperatively, both in the DV-SS-Si group. Overall, the two groups were comparable in terms of oncological outcomes (χ2 <0.001, P = 1.00). For patients with localized T1 renal cancer, partial nephrectomy (PN) is regarded as the standard treatment and can be performed via an open, laparoscopic, or robotic approach. Compared with other approaches, robotic platforms have several advantages, such as improved visualization, meticulous dissection, and easy intracorporeal suturing, which are beneficial for complex nephron-sparing surgeries. The KD-SR is a novel robotic surgical platform developed by SuZhou KangDuo Robot Co., Ltd., in China. The feasibility and safety in RAPN have been demonstrated before[1] and this study aimed to illustrate the HRQoL and oncological outcomes to provide evidence for its further application. HRQoL provides important evidence of both the physical and psychological effects of the overall quality of treatment. For patients suffering from renal tumors, previous studies have shown variation. In a prospective study with 100 patients who underwent RAPN,[2] only mental health improved significantly after 3 months and a significant improvement was found in more domains after 6–12 months. However, Sandbergen et al[3] reported an initial decrease in the HRQoL of patients who underwent PN after 1 month and a significant improvement after 1 year. In the current study, we observed improvements in HRQoL at 3 months postoperatively, but no significant impairment was found. In comparison, we found more domains with significant improvements in both the KD-SR and DV-SS-Si groups after 3 months. A similar result was reported in bladder cancer patients by Vejlgaard et al,[4] in which HRQoL was shown to be stable or significantly improved apart from sexual functioning at 90 days after radical cystectomy. These results indicated the favorable impacts of the KD-SR on RAPN both mentally and physically. Additionally, no significant difference was found in the score changes after 3 months between the two groups, although the DV-SS-Si group had better scores in several domains at 3 months. Thus, the KD-SR achieved similar results compared with the DV-SS-Si in terms of HRQoL. However, since only one HRQoL evaluation was planned after the surgery in this study, a potential bias of the intense focus on postoperative health cannot be overlooked as patients tended to report a better perceived quality of life since they felt well observed. A long-term evaluation of HRQoL with more planned assessments is expected to demonstrate the long-term effects on HRQoL and the trend of scores. In a prospective study of 124 patients with T1 renal tumors who underwent RAPN,[5] metastasis was reported in 1 patient (0.8%), and no local recurrence was found at the 2-year follow-up. Similarly, no recurrence or metastasis was reported in the KD-SR group at the 2-year follow-up, while 1 (3.2%) recurrence and 1 (3.2%) metastasis were reported in the DV-SS-Si group.[5] Therefore, the KD-SR achieved similar medium-term oncological outcomes compared to the DV-SS-Si. There are several different design features of the two systems. For example, the KD-SR is an open vision system in the surgeon console adapted with a foot clutch for the switching system, while the DV-SS-Si is an immersive vision system with a manual clutch. For the patient cart, the DV-SS-Si is equipped with four arms in contrast to three arms for the KD-SR. In addition, the KD-SR is equipped with a three-dimensional vision system, which requires extra glasses to view and is compatible with commercially available three-dimensional endoscopy systems such as STORZ, OLYMPUS, etc., providing an excellent visual operative field. However, the KD-SR still needs improvement. For example, similar to DV-SS-Si, KD-SR lacks a tactile feedback system, which allows precise force control and less tissue damage. To compensate, the improved three-dimensional high definition visualization of the KD-SR allows the perception of tissue consistency and suture tension. Several limitations of this study should be mentioned. First, despite being a prospective randomized cohort trial, only a small number of patients were included, and follow-up of only one HRQoL assessment, EORTC QLQ-C30, was planned. Second, all enrolled patients were diagnosed with a T1a renal cancer. Also, the follow-up duration was only 2 years, which was limited for the evaluation of T1a renal cancer recurrence and metastasis. In conclusion, for patients undergoing RAPN for T1a tumors, the KD-SR achieved similar results compared to DV-SS-Si in terms of HRQoL and medium-term oncological outcomes. It may offer a new option, but more clinical trials are needed. Conflicts of interest None.