Data on patients who underwent RACS and LCS from January 2021 to June 2024 at Tianjin Medical University Cancer Institute & Hospital (TJMUCH) were collected. Although the third-generation da Vinci robotic system was introduced at our center in 2019 to initiate robotic colorectal cancer surgeries, only cases from 2021 onwards were included to avoid data bias associated with the initial learning curve. The patients’ data were categorized into RACS and LCS groups. Patient inclusion criteria: (1) Preoperative diagnosis: CRC was confirmed via preoperative endoscopic pathology; (2) Operability of tumor: Patients with unresectable colon or high rectal tumors, or those with mid-to-low rectal cancer classified as T3 or higher or with regional lymph node metastasis, were required to undergo neoadjuvant therapy to enable complete tumor resection prior to surgery; (3) Surgical indications: The patient met the standard indications for surgery, with a single primary colorectal tumor or a single primary tumor accompanied by a resectable metastatic lesion. Additionally, the patient was able to tolerate RACS or LCS and had no severe complications that would contraindicate minimally invasive treatment; (4) Patient consent and willingness: Patients expressed a willingness to undergo either RACS or LCS, and provided informed consent for their participation in the procedure.

RACS, using the da Vinci Si and Xi systems (Intuitive Surgical, USA), provides 3D high-definition imaging and multi-joint instruments, enabling precise operations by a two-person team (surgeon and first assistant). LCS, utilizing 2D imaging and straight instruments from KARL STORZ (Germany) and Stryker (USA), requires a three-person team (surgeon, first assistant, and second assistant). All patients undergoing RACS or LCS for colon cancer underwent a complete mesocolic excision (CME), while those with rectal cancer received a total mesorectal excision (TME). For patients with mid-to-low rectal cancer eligible for rectal-colonic anastomosis, the decision to perform an ileostomy was based on intraoperative assessment of anastomotic integrity, bowel perfusion, postoperative tension on the anastomotic site, and whether the patient had undergone neoadjuvant therapy. In both surgical methods, port placement and patient positioning were optimized to provide the surgeon with clear access to the surgical field, following the principles of CME and TME. In cases where significant intraoperative blood loss occurred, advanced local tumor staging was identified, or the patient exhibited abnormal vital signs during the minimally invasive procedure, the surgery was converted to open surgery.

Key clinical and pathological characteristics, as well as perioperative outcomes, were compared between the two groups. Patient demographic data, including age and gender, as well as clinicopathological variables such as histological type, tumor differentiation, the American Joint Committee on Cancer (AJCC) pathological T stage (pT stage) and pathological N stage (pN stage), cancer nodule, and so on, were collected and analyzed. Surgical parameters, including lymph nodes dissection (LND), the duration of surgery, intraoperative blood loss, surgical site distribution (rectum and sigmoid colon), etc., were also assessed.

Data were analyzed with GraphPad Prism 10.0.2. Categorical variables were compared using the Chi-square test or Fisher’s exact test, while continuous variables were assessed using either the t-test or the Mann–Whitney U−test. Significance was determined with p-value less than 0.05.

A total of 225 patients with CRC were included in the study, including 82 cases of RACS and 143 cases of LCS. As shown in Table 1 , there were statistically significant differences between RACS group and LCS group in terms of histological type (p = 0.015) and surgical site (p < 0.0001). Patients in RACS group had a higher prevalence of adenocarcinoma (40.24% vs. 27.97%) and a lower occurrence of mixed histological types (9.76% vs. 27.27%) than those in LCS group. In our medical center, the surgical sites of RACS primarily focused on the rectum and sigmoid colon, with rectal cancer accounting for 87.80% of the cases. However, there were no statistically significant differences between two groups in terms of age, gender, differentiation, pT stage, pN stage, presence of cancer nodules, and the administration of neoadjuvant chemotherapy (p > 0.05 for all).

The data in Table 2 showed patients undergoing RACS had a significantly longer median surgery duration (218.5 minutes vs. 165 minutes, p < 0.0001) and greater median blood loss (100 mL vs. 50 mL, p < 0.0001) compared to those undergoing laparoscopic surgery (LCS). The median hospitalization cost was also higher in RACS, at 117,822 RMB (range: 78,225–1,627,735) compared to 78,174 RMB (range: 49,582–1,466,659) for LCS (p < 0.0001). Both groups had a similar median lymph node dissection count (RACS: 16, LCS: 15, p = 0.931) and median postoperative hospital stay (7 days, p = 0.475). Conversion to laparotomy, Clavien-Dindo classification, and postoperative complications, including anastomotic leakage, were low and comparable between groups (p > 0.05). The most common postoperative complications among patients with RACS or LCS are anastomotic leakage (3.66% for RACS; 4.20% for LCS) and bleeding (2.44% for RACS; 2.10% for LCS, Table 3 ).

Since RACS in our medical center was only performed on the rectum and sigmoid colon, to prevent significant bias due to substantial differences in surgical sites, 109 patients who underwent LCS for the rectum and sigmoid colon were included for comparison with RACS. The operative time for patients undergoing robotic surgery was significantly longer than for those undergoing laparoscopic surgery (Median duration: 218.5 minutes for RACS vs. 160 minutes for LCS; p < 0.0001). The robotic-assisted surgery group had greater blood loss compared to the laparoscopic surgery group (Median blood loss: 100 mL for RACS vs. 50 mL for LCS; p < 0.0001). The RACS group had a higher proportion of rectal surgery patients (87.80% vs. 72.48%) and fewer sigmoid colon surgery patients (12.20% vs. 27.52%) compared to the LCS group (p = 0.01). The above two groups showed no statistically significant differences in age, gender, LND (above or below 12), number of LND, length of postoperative hospital stay, conversion to laparotomy, postoperative complications, anastomotic leakage, rectal surgical technique or ileostomy proportion (p > 0.05 for all, Table 4 ). In Table 4 , among the 109 patients in the LCS group, 79 underwent rectal surgery, with 73 undergoing DIXON procedures, of which 33 had an ileostomy (45.2%, 33/73). In the RACS group, out of 82 patients, 72 underwent rectal surgery, with 67 undergoing DIXON procedures, of which 35 had an ileostomy (52.2%, 35/67).

As was shown in Table 5 , the median operative time for RACS at TJMUCH was 218.5 minutes. This was slightly longer than the average time reported by Gansu Provincial Hospital in China (205.9 minutes) and exceeds the median time at most hospitals in China (180 minutes). However, it was shorter than the median operative time at Ljubljana medical center in Slovenia (262 minutes) or Illinois medical center in USA (347 minutes). The median intraoperative blood loss of patients undergoing RACS at TJMUCH (100mL) was lower than the average blood loss at Gansu Provincial Hospital in China (147.8mL), the median blood loss at hospitals in most regions of China (104mL), and the median blood loss at a hospital in the state of Illinois, USA (150mL). Moreover, RACS for rectal cancer accounted for a very high proportion in Chinese and international medical centers. The RACS proportion of rectal cancer cases at TJMUCH was generally the highest compared to other medical centers. The mean total hospitalization cost for robotic surgery at our center (117,584 RMB) was higher than that of Gansu Provincial Hospital (84,990 RMB).

During RACS, a 3D visual field is used, providing a clearer view compared to the 2D visual field of LCS. However, based on the images in Figures 1A, B , our center believes that LCS offers advantages in terms of the tissue retraction, the dissection field around the root of the inferior mesenteric artery, and the tension on the inferior mesenteric nerves compared to RACS.