Oncologic outcomes of single-incision laparoscopic surgery versus conventional laparoscopic surgery for colorectal cancer (CSILS): study protocol for a multicentre, prospective, open-label, non inferiority, randomized controlled trial

Background: In most previous studies, single-incision laparoscopic surgery (SILS) for colorectal cancer (CRC) was feasible and safe in the short term. However, long-term oncologic outcomes remain uncertain, as only a few studies contained long-term survival data. SILS for CRC is still in the early stages of research. Further studies, particularly large-scale, prospective randomized controlled trials, are necessary to assess the value of SILS for CRC. Methods: This study is a prospective, multicentre, open-label, noninferiority, parallel-group randomized controlled trial that investigates the long-term oncologic outcomes of SI LS compared to conventional laparoscopic surgery (CLS) for CRC. A total of 710 eligible patients will be randomly assigned to the SILS group or the CLS group at a 1:1 ratio using a central, dynamic, and stratified block randomization method. Patients with ages ranging from 18 to 85 years old, of both sexes, with CRC above the peritoneal reflection diagnosed as cT1-4aN0-2M0 and a tumour size no larger than 5 cm will be considered for the study. The primary endpoint is 3-year disease-free survival (DFS). The secondary endpoints include: intraoperative outcomes, postoperative recovery, postoperative pain assessment, pathological outcomes, early morbidity and mortality rate, cosmetic effects, quality of life, 3-year overall survival (OS), incidence of incisional hernia, 5-year DFS and 5-year OS. The first two follow-up visits will be scheduled at one month and three months postoperatively, then every three months for the first two years and every six months for the next three years. Discussion: Currently, no randomized controlled trials (RCTs) have been designed to investigate the long-term oncologic outcomes of SILS for CRC. This study is expected to provide clinical evidence of the oncologic outcomes of SILS compared to CLS for CRC to promote its widespread use.