Study design
Patients who received LISR or LAPR for ultra-low rectal cancer located below the peritoneal reflection at the Guangxi Cancer Hospital, between Between April 2014 and December 2015 were assessed retrospectively. Our methodology conformed to the principals outlined in the Declaration of Helsinki[8]. The patients were fully informed about the operation and a detailed inform consent form reporting the operation details were signed by the patients. In addition to routine investigations, computed tomography (CT) of chest, abdomen and pelvis, positron emission tomography-computed tomography (PET-CT), and colonoscopy was performed in all patients as part of preoperative work-up.
Patient demographics, preoperative and operative data, and outcomes were included in the analysis. Key variables of interest included age, sex, body mass index (BMI), preoperative diagnosis, duration of surgery, duration of ileocolic anastomosis, intraoperative blood loss, total length of hospital stay, postoperative duration of intestinal function recovery, postoperative pain, and incidence of postoperative in-hospital complications (infection, obstruction, and bleeding). Pathological data, including tumor-node-metastasis (TNM) stage and the number of nodes dissected, were also reviewed. All pathological data fell into the category of T1–4NxM0.
Inclusion Criteria For ISR
ISR was offered to patients with preoperative T1–4 tumors that were circumferential resection margin (CRM) negative according to the TNM classification (seventh edition) and showed no evidence of extension into the external anal sphincter or the levator ani muscle and to those in whom resection could be performed with a distal margin of at least 2 cm for T2 or T3 tumors or 1 cm for T1 tumors. Patients with prior history of abdominal surgery, previous malignancy or those who had psychiatric disorders or severe organ dysfunction such as severe cardiopulmonary disorders were excluded.
Neoadjuvant chemoradiotherapy (NAC) was performed for patients with tumors that invaded the other organs or structures (T4)[9]. Patients with stage III tumor who provided their informed consent for adjuvant chemotherapy were given postoperative systemic chemotherapy with a 5-fluorouracilbased regimen.
Surgical Procedure For LISR And LAPR
A circular incision of the rectal mucosa and of the internal muscular layer was made at least 1 cm below the lower margin of the tumor via a transanal dissection. LISR was basically performed according to the methods described by Schiessel and colleagues. In the abdominal approach, ligation and dissection were performed at the root of the inferior mesenteric artery with mobilization of the splenic flexure. The rectum was mobilized to the level of the puborectalis muscle using the technique of total mesorectal excision (TME). Autonomic nerve preservation was routinely performed for patients without tumors invading the nerves. Dissection of the intersphincteric space between the internal anal sphincter and the external anal sphincter was advanced as low as possible from the abdomen to facilitate the transanal approach. After the operator moved to a transanal approach, the rectum and anal canal were irrigated with povidone iodine and saline to prevent scatter of cancer cells. Following closure of the anal orifice at the distal cut end, the internal sphincter was circumferentially incised, and the intersphincteric plane was dissected. After specimen removal and irrigation of the pelvic cavity, lateral pelvic lymph node dissection was performed for advanced.
The surgical procedure for LAPR was as previous descripted [10].
Follow-up And Oncologic Outcomes
All patients were followed on an outpatient basis. Patients were examined with chest and abdominopelvic CT and carcinoembryonic antigen measurement every 3 months for 1 years and then yearly for at least 3 years. The date and first site of recurrence were recorded for each patient. Local recurrence was defined as intrapelvic recurrence, recurrence at the pelvic floor or anastomotic site, or recurrence at lateral pelvic lymph nodes. Other recurrences were defined as distant metastases.
Meta-analysis
Search strategy: The Pubmed, Embase, Cochrane Library electronic databases, and Wanfang Data and DNKI (China National Knowledge Infrastructure) were searched for comparative studies published up to January 2020. The following medical subject heading (MeSH) terms and words were used for the search in all possible combinations: “Intersphincteric Resection,” “ISR,” “Abdominoperineal Resection,” “ARC,” “laparoscopic,” and “laparoscopy.”
A manual search of the reference lists of relevant articles was also performed. No language or time restriction was used. Data were extracted from each study by two independent reviewers (Xianwei Mo and Hao Lai). Disagreements were resolved by consensus.
Eligibility criteria: Inclusion criteria were described as follows: (1) The study design was a case-match design (randomized, controlled trials (RCTs) or controlled clinical trials (CCTs)) that compared LISR to LARC; (2) LISR or LARC can be performed using any type of laparoscopic or endoscopic instruments; (3) studies that were included contained information on at least one of the following outcome measures: disease free survival rate (DFS), and 5-years overall survival rate (OS). Exclusion criteria were as follows: (1) case reports, reviews, and quasi-randomized trials; and (2) over-lapping data.