Robotic-assisted radical colorectal cancer surgery with the KangDuo surgical robotic system vs. the da Vinci Xi surgical system in elderly patients: A multicenter randomized controlled trial

To the Editor: Recently, a novel robotic surgical platform, the KangDuo surgical robot (KD-SR), has emerged in China. As depicted in Supplementary Figure 1, https://links.lww.com/CM9/C379, the KD-SR-01 system integrates an open vision system, which not only enables a natural posture for surgeons and mitigates potential neck strain, but also enhances effective communication between the primary surgeon and their assistant. Previous studies have demonstrated encouraging outcomes of this novel robotic surgical system in certain instances.[1] By the end of 2019, China’s elderly population aged ≥60 years had surged to a staggering 253 million individuals, constituting an impressive 18.1% of the total populace.[2] Elderly colorectal cancer (CRC) patients are featured by lower health performance status, more cautious perioperative risk evaluation, worse surgical tolerance, and more postoperative complications. Hence, the outcomes of the KD-SR system for elderly patients is a pivotal inquiry in its clinical advancement for treating CRC. Regarding robotic surgical platforms, the da Vinci robot’s dominance in global surgical robotics stems from its proven track record in delivering improved patient outcomes along with increased surgeon efficiency.[3] Furthermore, the da Vinci robot provides a standardized platform for robotic-assisted surgeries. Thus, we aimed to assess the outcomes of the KD-SR-01 in elderly CRC patients by comparing it with the da Vinci Robotic System through a multicenter randomized controlled trial. This multicenter prospective randomized controlled trial was conducted from July 2022 to May 2023 at Peking University First Hospital (Center I), the Second Affiliated Hospital of Harbin Medical University (Center II), and the First Affiliated Hospital of Chongqing Medical University (Center III). The original protocol was registered at www.chictr.org.cn (ChiCTR2200063172). The study was approved by Ethics Committee of Drug Clinical Trials, Chinese Academy of Medical Sciences and Peking Union Hospital (No. KS2022261). Written informed consent was obtained from all patients after providing a comprehensive explanation regarding the study’s objectives. Inclusion criteria included: (1) confirmation of colorectal adenocarcinoma through pathological biopsy; (2) age 60 years or older; (3) absence of extensive infiltration and metastasis as observed on imaging; (4) American Society of Anesthesiologists Physical Status Classification System grade I–II classification; and (5) voluntary participation in this trial with informed consent provided. Exclusion criteria included: (1) patients with familial adenomatous polyposis or cancerous lesions resulting from ulcerative colitis; (2) individuals unable to tolerate anesthesia and luminal surgery procedures; (3) body mass index (BMI) >30 kg/m2; (4) presence of intestinal obstruction, hemorrhage, or perforation necessitating emergency surgery; and (5) participants concurrently involved in other investigational drug or device clinical trials that were not yet completed. Withdrawal criteria included: (1) the subject’s withdrawal of informed consent; (2) the investigator’s determination that the subject was no longer suitable for continuation within the clinical trial; (3) death of the subject; (4) loss to follow-up; and (5) sponsor’s request for termination of the trial. All surgeries were performed by expert surgeons from three large tertiary centers with experience of >100 standard robotic surgical procedures (Prof. Yi Xiao in Center I, Prof. Guiyu Wang in Center II, and Prof. Zhengqiang Wei in Center III). More detailed surgical procedures are given in Supplementary Method and Supplementary Figure 2A–I, https://links.lww.com/CM9/C379. In this study, the primary outcomes were surgical success and conversion rates. The secondary outcomes were time to first flatus, National Aeronautics and Space Administration task load index (NASA-TLX) score, and operational experience score. The NASA-TLX was employed for subjective evaluation, utilizing the Paper/Pencil Version.[4] To simplify its application, we made modifications to the original NASA-TLX continuous rating scale (0–100), transforming it into a 10-point scale while eliminating the weighting process. The ratings were then straightforwardly summed up to provide an estimation of overall workload.[1] Safety datums included total operative time, docking time, console time, blood loss, postoperative adverse events, number of harvested lymph nodes, negative margins, ultrasonography, and laboratory tests. The Clavien-Dindo classification system was employed for the evaluation of all adverse events.[5] Ultrasonography was performed on postoperative weeks 4. Laboratory parameters for follow-up included measurement of serum white blood cell (WBC), hemoglobin (Hb), neutrophil (NEUT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) on postoperative day 1, day 3, and postoperative weeks 4. Non-normally distributed continuous variables were analyzed by Mann–Whitney’s U test. Categorical data were analyzed by the Chi-square test or Fisher’s exact probability method. Statistical significance was set at P <0.05. As shown in Supplementary Figure 3, https://links.lww.com/CM9/C379, a total of 65 CRC patients with robot-assisted colorectal surgery (25 patients in Center I, 28 patients in Center II, and 12 patients in Center III) were enrolled in this study and assigned to either the da Vinci Xi surgical system (DV-Xi) group (33 patients) or KD-SR group (32 patients). No notable difference could be found between the DV-Xi group and KD-SR group regarding sex (P = 0.649), age (P = 0.537), BMI (P = 0.584), ASA grade (P = 0.492), comorbidity (P = 0.492), tumor location (P = 0.924), tumor differentiation (P = 1.000), histologic type (P = 0.614), pT stage (P = 0.822), pN stage (P = 0.492), TNM stage (P = 0.480), and maximum tumor diameter (P = 0.859) [Supplementary Table 1, https://links.lww.com/CM9/C379]. In DV-Xi and KD-SR groups, all surgeries were successfully performed without the need for conversion to open or laparoscopic surgery. There was no significant difference in terms of time to first flatus between the two groups (P = 0.738). Moreover, the KD-SR group had comparable outcomes to the DV-Xi group in mental demand (P = 0.946), physical demand (P = 0.532), temporal demand (P = 0.513), performance (P = 0.373), effort (P = 0.824), frustration (P = 0.811), and NASA-TLX scores and operational experience score (P = 0.492) [Table 1]. Table 1 - Outcomes and safety comparison of DV-Xi and KD-SR in the treatment of elderly colorectal cancer patients. Items DV-Xi group (n = 33) KD-SR group (n = 32) P-value Success 33 (100) 32 (100) – Conversions 0 (0) 0 (0) – Time to first flatus (h) 28.0 (20.5, 44.5) 33.5 (18.0, 47.5) 0.738* NASA-TLX Mental demand 3.0 (1.0, 4.0) 2.0 (1.0, 4.0) 0.946* Physical demand 3.0 (2.0, 4.0) 2.0 (1.3, 4.0) 0.532* Temporal demand 2.0 (1.0, 4.0) 2.0 (1.0, 3.0) 0.513* Performance 2.0 (1.0, 3.5) 1.5 (1.0, 3.0) 0.373* Effort 2.0 (1.0, 4.0) 2.0 (1.0, 4.0) 0.824* Frustration 2.0 (1.0, 3.0) 2.0 (1.0, 3.0) 0.811* Operation feeling score Well 0 (0) 0 (0) 0.492† Moderate 33 (100) 31 (96.9) Poor 0 (0) 1 (3.1) Bad 0 (0) 0 (0) Total operative time (min) 155.0 (130.0, 190.5) 175.0 (129.8, 210.0) 0.237* Docking time (min) 5.1 (4.3, 6.5) 3.5 (4.3, 6.2) 0.230* Console time (min) 65.5 (44.6, 115.8) 63.1 (49.6, 90.2) 0.927* Blood loss (mL) 50.0 (20.0, 50.0) 50 (30.0, 57.5) 0.261* Number of harvested lymph nodes 16 (12, 20) 15 (12, 18) 0.363* Negative margins No 0 (0) 0 (0) 1.000† Yes 33 (100) 32 (100) Clavien-Dindo grade II or higher 3 (9.1) 1 (3.1) 0.613† Adverse events 9 (27.3) 8 (25.0) 0.835† Serious adverse events 5 (15.2) 2 (6.3) 0.427† Data are expressed as n (%) or median (Q1, Q3). *Mann–Whitney’s U test. †Fisher’s exact test. DV-Xi: the da Vinci Xi surgical system; KD-SR: the KangDuo surgical robot; NASA-TLX: National Aeronautics and Space Administration task load index. The median operative time was 155.0 (Q1–Q3: 130.0–190.5) min in the DV-Xi group and 175.0 (Q1–Q3: 129.8–210.0) min in the KD-SR group, with no statistically significant difference observed between the two groups (P = 0.237). Additionally, there was no significant difference regarding docking time (median time, KD: 3.5 min vs. DV: 5.1 min, P = 0.230) and console time (median time, KD: 63.1 min vs. DV: 65.5 min, P = 0.927) between the two groups. No significant disparity in blood loss was detected between the KD-SR (median, 50 mL) and DV-Xi groups (median, 50 mL) (P = 0.261) [Table 1]. Analysis of pathological data demonstrated that patients in the KD-SR and DV-Xi groups had similar results regarding the number of harvested lymph nodes (KD-SR: median, 15; Q1–Q3, 12–18. vs. DV-Xi: median, 16; Q1–Q3, 12–20, P = 0.363) and no positive surgical margins were noted in the two groups (P = 1.000). Adverse events occurred in 8 (25.0%) of 32 patients in the KD-SR group and 9 (27.3%) of 33 patients in the DV-Xi group (P = 0.835), including 2 (6.3%) serious adverse events (2 intra-abdominal infection) in KD-SR group and 5 (15.2%) serious adverse events (2 intra-abdominal infection, 1 rectovaginal fistula and 2 ileus) in DV-Xi group (P = 0.427). The incidences of postoperative complications of Clavien-Dindo grade II or higher were also comparable (KD-SR: 3.1% vs. DV-Xi: 9.1%, P = 0.613) [Table 1]. After systematic treatment, the symptoms resolved and all patients were discharged from the hospital safely. A follow-up ultrasound examination at four weeks post-operation did not reveal any abnormal findings. Regarding the follow-up of laboratory parameters including WBC, Hb, NEUT, ALT, and AST, only preoperative WBC level in KD-SR group was notably higher than DV-Xi group (median, KD-SR: 6.6 × 109/L vs. 5.6 × 109/L, P = 0.022) within the normal range, showing no clinical significance, and the KD-SR group had similar results to the DV-Xi group regarding other serum indicators (all P >0.05) [Supplementary Figure 4A–E, https://links.lww.com/CM9/C379]. In this study, we have compared the short-term outcomes and surgical safety between DV-Xi and KD-SR groups using the subgroup data of a randomized controlled study. In DV-Xi and KD-SR groups, all surgeries were successfully performed without the need for conversion to open or laparoscopic surgery. Furthermore, our findings indicated that patients in the KD-SR group exhibited a comparable postoperative gastrointestinal function recovery to those in the DV-Xi group. In this study, NASA-TLX score and operational experience score suggested that surgeon would not have additional operating discomfort when using the KD-SR-01 system, which may account for the similar total operative time, docking time, console time, and blood loss between the two groups. Meanwhile, in terms of pathological outcomes, all patients in our trial exhibited negative surgical margins, signifying the high quality of the surgical procedures. The numbers of harvested lymph nodes in the KD-SR group were found to be comparable to those in the DV-Xi group. In this study, the incidence of postoperative complications in the KD-SR group was not higher than that in the DV-Xi group, and all patients were safely discharged from the hospital with no abnormal findings in the follow-up ultrasound examination at four weeks post-operation. Furthermore, to investigate potential disparities in the impact of robotic surgery on the body’s internal environment, postoperative laboratory examinations including WBC, Hb, NEUT, AST, and ALT were conducted in this study; and we found the comparable results between KD-SR and DV-Xi groups. However, there are still several limitations in this study. First, a longer follow-up is necessary to evaluate the oncologic and functional outcomes of robot-assisted laparoscopic radical surgery with the KD-SR-01 system in elderly CRC patients. Second, the study cohort was relatively small and the impact of confounding factors on the outcome may be amplified due to the limited sample size. Consequently, it is imperative to conduct a randomized clinical trial with a larger sample size to gain more comprehensive insights. In conclusion, the findings suggest that KD-SR-01 may serve as a potential alternative to the Vinci Robotic System in terms of short-term outcomes and surgical safety, making it a viable option for robotic surgery in elderly patients with CRC. Funding This work was supported by the National Natural Science Foundation of China (No. 62276084) and the National Natural Science Foundation of China (No. U23A20482). Conflicts of interest None.