A Trial to Assess Robot-assisted Surgery and Laparoscopy-assisted Surgery in Patients With Mid or Low Rectal Cancer (COLRAR)

• Surgical quality based on pathological examination [ Time Frame: up to 4 weeks after operation ] [ Designated as safety issue: No ]
  A comparison of completeness of total mesorectal excision
  
  

• Postoperative morbidity [ Time Frame: up to 30 dyas after operation ] [ Designated as safety issue: Yes ]
  A comparison of the postoperative recovery variables, the postoperative complications and mortality
  
  
• Pelvic autonomic nerve preservation (intraoperative confirmation of pelvic nerve preservation) [ Time Frame: The day of operation ] [ Designated as safety issue: Yes ]
  During procedure, a surgeon indentify pelvic autonomic nerve and confirm whether the nerves are preserved or sacrified.
  
  
• Change from Baseline in QLQ 30, IIEF-5(5-item Version of the International Index of Erectile Function), IPSS(International Prostate Symptom Score), FSFI(Female Sexual Function Index), and Wexner's scoring [ Time Frame: up to 12months after operation ] [ Designated as safety issue: No ]
  EORTC QLQ 30:an assessment tool for measuring the quality of life IIEF-5 : an assessment tool for measuring male erectile function IPSS : an assessment tool for measuring voiding function FSFI : an assessment tool for measuring female sexual function Wexner's scoring : an asessment tool for measuring anal sphincter function Time points : 1,3,6, and 12months after operation
  
  
• 5-year overall survival rate [ Time Frame: up to 5 yearsa after operation ] [ Designated as safety issue: No ]
  A survival analysis will be performed using the Kaplan-Meier method, for which a comparison of the survival curve will also made using a Log-rank test.
  
  
• 5-year disease-free survival rate [ Time Frame: up to 5 years after operation ] [ Designated as safety issue: No ]
  A survival analysis will be performed using the Kaplan-Meier method, for which a comparison of the survival curve will also made using a Log-rank test.
  
  

Recently, the efficacy and oncological safety of laparoscopy has been demonstrated for treating colon cancer, and similar long-term results at 5-year confirmed by the several multicenter study trial. However, conventional laparoscopic surgery for rectal cancer is technically more difficult than colonic resection because of the confined space in the pelvis and the limitations of existing laparoscopic instruments which have a restricted range of movement compared with the provided by the surgeon's hand. Consequently, recent studies which compared short-term outcomes between open and laparoscopic rectal resections have reported higher rates of conversion to open surgery, positive circumferential margins, and increased anastomotic leakage in patients who underwent laparoscopic approach.

The da Vinci® Surgical System (Intuitive surgical, Sunnyvale, CA, USA) was introduced as the next advance in minimally invasive surgery to overcome the technical limitations of laparoscopy. The advantages of robotic assistance include enhanced dexterity, improved three-dimensional vision, and more intuitive instrument manipulation. This device eases the technical challenges of the minimally invasive approach and may make a complex surgical task more accessible to surgeons without extensive laparoscopic experience.

With its dependence on precise dissection in a narrow pelvic cavity, it is anticipated that rectal cancer surgery is one of the indications most likely to benefit from robot assistance. However, it is difficult to conclude whether robot assistance leads to better outcomes because few studies have directly compared the three existing techniques. Although robotic rectal excision has been reported to be safe and feasible in the recent literatures, a number of these results were based on small number of case series. There have been no randomized trials demonstrating the safety of robotic surgery in the treatment of rectal cancer. This study is designed to assess the efficacy and safety of robotic surgery compared with that of laparoscopic surgery for mid or low rectal cancer.