Abstract: Objective:To compare the clinical efficacies of Da Vinci robotic and laparoscopic total mesorectal excision (TME) for low rectal cancer.
Methods:The retrospective cohort study was conducted. The clinicopathological data of 64 patients with low rectal cancer who were admitted to the Third Xiangya Hospital of Central South University from October 2015 to January 2019 were collected. There were 42 males and 22 females, aged from 40 to 84 years,with a median age of 59 years. Of the 64 patients, 31 undergoing Da Vinci robotic TME and 33 undergoing laparoscopic TME were allocated into robotic group and laparoscopic group, respectively. Observation indicators: (1) surgical situations and postoperative recovery; (2) postoperative pathological examination; (3) follow-up. Follow-up using outpatient examination and telephone interview was conducted to detect long-term complications and pelvic autonomic nerve injury up to January 2020. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were represented as M (P25,P75), and comparison between groups was analyzed using the rank sum test. Count data were represented as absolute numbers, and comparison between groups was analyzed using the chi-square test or Fisher exact probability. Comparison of ordinal data between groups was analyzed using the Mann-Whitney U test.
Results:(1) Surgical situations and postoperative recovery: cases with anus preservation, cases with defunctioning stoma, cases with intraoperative conversion to laparotomy, cases with intraoperative blood transfusion, operation time, volume of intraoperative blood loss, time to postoperative first out-of-bed activities, time to postoperative first flatus, time to postoperative diet resumption, duration of hospital stay, cases with incision infection, cases with postoperative hemorrhage, cases with anastomotic fistula, cases with pulmonary infection, cases with urinary retention, comprehensive complication index for the whole group, comprehensive complication index for patients with complications, and treatment expenses of the robotic group were 30, 23, 0, 1, (285±73)minutes, (147±112)mL, (1.6±0.8)days, (3.6±1.1)days, (3.2±1.5)days, (9.8±2.8)days, 1, 4, 3, 1, 4, 15.0±12.0, 22.6(20.9,27.3), (11.7±1.2)×10⁴ yuan, respectively. The above indicators of the laparoscopic group were 22, 13, 2, 2, (253±57)minutes, (211±123) mL, (1.8±0.8) days, (3.9±1.6)days, (4.1±1.9)days, (11.8±4.3)days, 2, 5, 3, 3, 2, 20.0±12.0, 24.2(10.5,30.8), (7.7±1.3)× 10⁴ yuan, respectively. There were significant differences in the cases with anus preservation, volume of intraoperative blood loss, duration of hospital stay, and treatment expenses between the two groups (x²=8.581, t=-2.065,-2.133, 12.700, P<0.05). There was no significant difference in the cases with defunctioning stoma, operation time, time to postoperative first out-of-bed activities, time to postoperative first flatus, time to postoperative diet resumption, comprehensive complication index for the whole group, or comprehensive complication index for patients with complications between the two groups (x²=2.425, t=1.957,-0.679,-0.846,-1.941,-1.867, Z=-0.850, P>0.05). There was no significant difference in the cases with intraoperative conversion to laparotomy, cases with intraoperative blood transfusion, cases with incision infection, cases with postoperative hemorrhage, cases with anastomotic fistula, cases with pulmonary infection, or cases with urinary retention between the two groups(P>0.05). One patient with anastomotic fistula in the robotic group was clipped under endoscopy, and the other patients with complications were cured after symptomatic treatment. (2) Postoperative pathological examination: distance from tumor to surgical margin, tumor diameter, case with positive or negative surgical margin, cases with highly, highly-moderately, moderately, moderately-poorly, poorly differentiated tumor (tumor differentiation degree), cases in stage Ⅰ, Ⅱ, Ⅲa+b, Ⅲc+Ⅳ (tumor pathological stage), the number of lymph node dissected were 1.0 cm(0.3 cm,2.0 cm), (3.5±1.1)cm, 2, 29, 3, 7, 14, 5, 2, 5,18, 4, 4, 16.0±2.8 of the robotic group, respectively, versus 1.3 cm(0.5 cm,3.0 cm), (4.2±1.4)cm, 2, 30, 1, 7, 16, 6, 3, 1, 19, 7, 6, 13.9±3.8 of the laparoscopic group. There was a significant difference in the number of lymph node dissected between the two groups (t=2.420, P<0.05) . There was no significant difference in the distance from tumor to surgical margin, tumor diameter, tumor differentiation degree, or tumor pathological stage between the two groups (Z=-0.980, t=-1.912, Z=-0.809,-1.595, P>0.05). There was no significant difference in the surgical margin between the two groups (P>0.05). (3) Follow-up: of the 31 patients in the robotic group, 29 were followed up for 3-24 months, with a median follow-up time of 12 months. Of the 33 patients in the laparoscopic group, 30 were followed up for 3-36 months, with a median follow-up time of 15 months. Cases with intestinal obstruction, cases with timely stoma closure, cases with local recurrence, cases with distant metastasis, cases with death, Wexner score at postoperative 12 months, international prostate symptom score at postoperative 12 months, times of nocturia at postoperative 12 months, international index of erectile function of the robotic group were 2, 20, 3, 2, 2, 0.0(0.0,0.0), 4.5(1.3,8.8), 1.5(1.0,2.0), 2.0(1.3,10.8), respectively. The above indicators were 4, 7, 3, 2, 3, 1.0(0.0,3.0), 8.0(2.0,14.3), 2.0(1.0,4.0), 3.0(1.0,11.8) of the laparoscopic group. There was no significant difference in the cases with intestinal obstruction, cases with timely stoma closure, cases with local recurrence, cases with distant metastasis, or cases with death between the two groups (P>0.05). There were significant difference in the Wexner score and times of nocturia at postoperative 12 months between the two groups (Z=-2.202,-1.986, P<0.05). There was no significant difference in the international prostate symptom score and international index of erectile function at postoperative 12 months between the two groups (Z=-0.885, 0.094, P>0.05).
Conclusion: Both Da Vinci robotic and laparoscopic TME for low rectal cancer are safe and effective, of which the former can improve the anal sphincter retention rate, reduce the nocturia frequency and enhance the protection of defecation function under the premise of radical resection of tumor.