[Comparison of the mid- and long-term outcomes between natural orifice specimen extraction surgery and conventional laparoscopic surgery with abdominal auxiliary incision in the treatment of rectal cancer based on propensity score matching method].

To compare the mid- and long-term outcomes between natural orifice specimen extraction surgery (NOSES) and conventional laparoscopic surgery with abdominal auxiliary incision in the treatment of rectal cancer. A propensity score matching study was conducted. Patients with pathological diagnosis of rectal adenocarcinoma, preoperative imaging assessment of T1-3 and body mass index <28 kg/m(2) were included. Those who underwent local resection or abdominoperineal resection, had simultaneous multiple primary cancers, malignant intestinal obstruction or perforation, received neoadjuvant radiotherapy, and were unsuitable for laparoscopic surgery were excluded. From January 2017 to January 2019, 264 patients undergoing laparoscopic rectal cancer surgery at the Department of Colorectal Tumor Surgery, Shengjing Hospital of China Medical University were enrolled in this study, and divided into the NOSES group (52 cases) and the auxiliary incision group (212 cases). Propensity score matching method was used as 1:1 to match the initial data, and 46 pairs were finally obtained. SPSS 26.0 was used for data analysis, and 2-year disease-free survival, intraoperative and perioperative indicators were compared between the two groups. The tumor short diameter in the NOSES group and the auxiliary incision group was (2.9±0.8) cm and (3.1±1.0) cm (=0.842, =0.402) respectively. Other baseline data were also comparable between the two groups(all >0.05). There were no significant differences in operative time, intraoperative blood loss, length of hospital stay and postoperative complication rate between the two groups (all >0.05). The time to first flatus [2 (1-6) days vs. 3 (1-6) days, =-3.035, =0.002] and to liquid food intake [3 (1-6) days vs. 3 (2-7) days, =-2.587, =0.010] after surgery in the NOSES group were earlier than those that in the auxiliary incision group. Compared with the auxiliary incision group, the postoperative pain score was lower [3 (2-5) vs. 4 (3-7), =-5.477, <0.001], and the aesthetic score was higher [8 (6-9) vs. 7 (5-8), =-6.329, <0.001] in the NOSES group. The distal resection margin in the NOSES group was longer than that in the auxiliary incised group [(3.7±1.2) cm vs. (2.9±1.4) cm, =3.287, <0.001]. There were no significant differences in proximal resection margin the number of harvested lymph nodes and positive rate of circumferential resection margin between the two groups (all >0.05). The 2-year disease-free survival rate in the NOSES group and the auxiliary incision group was 93.5% and 89.1% respectively, and the difference was not statistically significant (=0.466). NOSES has similar mid- and long-term outcomes to conventional laparoscopic surgery and the advantages of better cosmetic effect, less postoperative pain and faster recovery, which is more in line with the concept of minimally invasive and worthy of clinical promotion.