Patients
This study was approved by the Ethics Committee of Guangdong Provincial People’s Hospital [No. GDREC2019296H(R1)] and was carried out in adherence with the Declaration of Helsinki.
Inclusion criteria: (1) Age 18-70 years; (2) Underwent laparoscopic low anterior resection for rectal cancer; (3) Postoperative pathology diagnosis of rectal adenocarcinoma. (4) Informed consent was signed prior to surgery in all cases. Exclusion criteria: (1) Preoperative neoadjuvant radiotherapy and chemotherapy; (2) Emergency surgery; (3) Preoperative and intraoperative detection of distant organ metastases or extensive implantation metastases in the abdominal cavity; (4) Intraoperative laparoscopic inability to complete the operation and intermediate open abdominal; (5) Postoperative pathology those who showed residual cancer cells at the proximal, distal, and circumferential incision margins; (6) Those who did not receive standard chemotherapy after TNM staging of stages II or III after surgery; (7) Patients with concomitant or atopic colorectal cancer and other organ tumors; (8) Patients with incomplete case data.
Based on the above criteria, we retrospectively collected data from the patients who undergone laparoscopic low anterior resection of rectal cancer at Guangdong Provincial People's Hospital from January 2014 to December 2015. A total of 384 cases were included in this study. Among them, 159 cases of LCA were preserved intraoperatively; while 225 cases of LCA were not preserved.
Surgical procedure
The patient was truncated under general anesthesia, pneumoperitoneum was established (pressure of 15 mmHg) and the abdominal cavity was explored. All patients underwent total mesenteric resection and D3 lymph node dissection with sphincter preservation [11]. For the LCA non-preservation group, the opening of the peritoneum proceeded cephalad, towards the duodenojejunal angle of Treitz, and the mesenteric root was incised 1 cm below the inferior margin of the pancreas. The aortomesenteric window was opened wide and the inferior mesenteric vessels were exposed. The inferior mesenteric artery was ligated and divided at 2 cm from its origin. The inferior mesenteric vein was ligated and divided below the pancreatic margin.
For the LCA preservation group, the opening of the peritoneum proceeded upward and then laterally towards the sigmoid colon. The left colic artery was identified and preserved while low ligation of the inferior mesenteric artery (the superior hemorrhoidal artery) was performed. Lymphadenectomy was performed medially along the inferior mesenteric artery as far as 2 cm from the aorta. For both groups, dissection was then continued windowing Toldt’s and Gerota’s fascias up to the parietocolic gutter. Intra-pelvic dissection was carried out through standardized planes. Dissection of the rectum starts by incision of the peritoneal fold in the pelvis. Mesorectal excision started posteriorly by dissection through Heald’s “holy plane” [12], it carried on towards the lateral region of the rectum, sparing the lateral part of the lateral rectal ligaments, and extended on the anterior side in front of Denonvilliers’ fascia [13].
After resection of the tumor, with the proximal bowel to the pubic symphysis assured to be free of tension, if not, then freed the colonic splenic flexure. Reconstruct the gastrointestinal tract with a tubular anastomosis performed end-to-end. A diverting ileostomy was performed based on the surgeon’s technical evaluation of the quality of the anastomosis.
Postoperative adjuvant chemotherapy
Patients with pathological stages II or III were treated with XELOX regimen (oxaliplatin, capecitabine) chemotherapy for 6-8 courses after surgery.
Parameters and postoperative follow-up
Parameters: operation time, intraoperative bleeding and intraoperative adverse events (e.g., presence of anastomotic tension, additional free colonic splenic flexure, etc.); postoperative anastomosis-related complications (anastomotic leakage, anastomotic bleeding and anastomotic stenosis, etc.); postoperative distance of the pathological tumor from the superior and inferior incision margins, total number of dissected lymph nodes and the number of positive lymph nodes.
Periodic patient follow-up with office visits for 5 years: every 3-6 months for 2 years after surgery; every 6-12 months for 3-5 years after surgery; once a year for 5 years after surgery. The follow-up included physical examination, CEA measurement, CT scan and colonoscopy. Confirmation of recurrence required imaging or pathological evaluation.
Statistical analyses
Statistical analyses were performed using SPSS (Statistical Product and Service Solutions 22.0 for Windows, SPSS Inc., Chicago, IL). Quantitative data are described as the mean ± standard deviation, and t-tests or rank sum tests were used to test the hypothesis. Qualitative data are described by the number of cases and percentages, and χ2 or Fisher’s tests were used to test the hypothesis. The Kaplan-Meier method was used to estimate survival, and the log-rank test was used to test differences between the survival curves. Statistical significance was considered to exist when P < 0.05.