Objective To investigate the clinical efficacy of Da Vinci robotic assisted and laparos-copic assisted complete mesocolic excision (CME) for right hemicolon cancer.

Methods The propensity score matching and retrospective cohort study was conducted. The clinicopatho-logical data of 119 patients with right hemicolon cancer who were admitted to Daping Hospital, Army Medical University from July 2016 to July 2019 were collected. There were 63 males and 56 females, aged (61±11)years. All the 119 patients underwent CME of right hemicolon. Of 119 patients, 37 cases undergoing Da Vinci robotic assisted CME of right hemicolon were divided into robotic group and 82 cases undergoing laparoscopic assisted CME of right hemicolon were divided into laparoscopic group. Observation indicators: (1) the propensity score matching conditions and comparison of general data between the two groups after propensity score matching; (2)intraoperative and postoperative situations; (3) postoperative pathological examination; (4)follow‑up. Follow‑up was conducted by outpatient examination or telephone interview to detect tumor metastasis and survival of patients after surgery up to August 2019. The propensity score matching was conducted by 1∶1 matching using the nearest neighbor method. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was conducted using the independent sample t test. Count data were represented as absolute numbers, and comparison between groups was conducted using the chi‑square test or Fisher exact probability. The Kaplan‑Meier method was used to calculate survival rate and the GraphPad Prism 5 software was used to draw survival curve. The Log‑rank test was used for survival analysis.

Results (1) The propensity score matching conditions and comparison of general data between the two groups after propensity score matching: 68 of 119 patients had successful matching, including 34 cases in each group. Before propensity score matching, cases undergoing surgery by surgeon A or surgeon B were 32, 5 of the robotic group, versus 49, 33 of the laparoscopic group, showing a significant difference between the two groups (χ²=8.381, P<0.05). After propensity score matching, the gender (males or females), age, body mass index (BMI), cases with tumor classified as stageⅠ, stage Ⅱ or stage Ⅲ of TNM staging, cases with tumor located at ileocecal region, ascending colon, hepatic flexor of colon or transverse colon, cases undergoing surgery by surgeon A or surgeon B were 17, 17, (62±10)years, (22.4±2.7)kg/m², 4, 14, 16, 3, 15, 10, 6, 29, 5 of the robotic group, versus 15, 19, (62±11)years, (22.4±2.8)kg/m², 4, 18, 12, 2, 19, 7, 6, 30, 4 of the laparoscopic group, showing no significant difference between the two groups (χ²=0.236, t=0.127, 0.044, χ²=1.071, 1.200, 0.000, P>0.05). (2) Intraoperative and postoperative situations: after propensity score matching, the operation time, volume of intraoperative blood loss, cases undergoing conversion to open surgery, time to postoperative initial out‑of‑bed activities, time to postoperative first flatus, time to postoperative initial liquid food intake, duration of postoperative hospital stay and treatment expenses were (235±50)minutes, (73±45)mL, 0, (1.9±0.7)days, (2.9±1.2)days, (3.1±2.4)days, (9.1±4.9)days, (9.6±1.8)×10⁴ yuan of the robotic group, versus (183±35)minutes, (74±74)mL, 1, (2.1±0.6)days, (3.3±1.4)days, (3.5±4.2)days, (9.1±3.9)days, (6.3±1.6)×10⁴ yuan of the laparoscopic group, respectively. There were significant differences in the operation time and treatment expenses between the two groups (t=5.050, 8.165, P<0.05) while there was no significant difference in the volume of intraoperative blood loss, time to postoperative initial out‑of‑bed activities, time to postoperative first flatus, time to postoperative initial liquid food intake or duration of postoperative hospital stay between the two groups (t=0.118, ‒0.462, ‒1.129, ‒1.291, 0.027, P>0.05). There was no significant difference in the conversion to open surgery between the two groups (P>0.05). Five patients of the robotic group and 7 patients of the laparoscopic group had postoperative complications. There was no significant difference in the postoperative complications between the two groups (χ²=0.405, P>0.05). (3) Postoperative pathological examination: after propensity score matching, cases with R₀ resection, the number of lymph node dissected, cases with lymph node metastasis and cases with tumor differentiation as well differentiated adenocarcinoma, moderately differentiated adeno-carcinoma, poorly differentiated adenocarcinoma or mucinous adenocarcinoma were 34, 17±5, 14, 1, 22, 6, 5 of the robotic group, versus 34, 17±5, 12, 2,20, 2, 10 of the laparoscopic group, respectively. There was no significant difference in the R₀ resection between the two groups (P>0.05) and there was no significant difference in the number of lymph node dissected, lymph node metastasis and tumor differentiation between the two groups (t=0.488, χ²=0.249, 4.095, P>0.05). (4) Follow‑up: after propensity score matching, 68 patients were followed up for 1‒36 months, with a median follow‑up time of 24 months. The follow‑up time was (20±13)months of the robotic group, versus (21±13)months of the laparoscopic group, showing no significant difference between the two groups (t=0.409, P>0.05). During the follow‑up, 3 cases of the robotic group and 4 cases of the laparoscopic group had tumor distant metastasis. The disease‑free survival rate and overall survival rate at postoperative 3 years were 83.9% and 86.8% of the robotic group, versus 82.0% and 86.6% of the laparoscopic group, showing no significant difference between the two groups (χ²=0.188, 0.193, P>0.05).

Conclusion Da Vinci robotic assisted CME for right hemicolon cancer is safe and feasible.