To investigates the feasibility, practicability, safety and subjective as well as functional outcome of transanal minimal invasive surgery toal mesentery excision for rectal cancer.

Natural orifice transluminal endoscopic surgery (NOTES) give the opportunity to reduce surgical access trauma leading to a more painless surgery and enhancing a fast postoperative recovery. Experience with transanal minimal invasive surgery(TAMIS) for rectal cancer show that such NOTES procedures are feasible and safe. And also, lots of experimental studies and small case series reporting the feasibility of transanal anterior resection with single incision laparoscopic surgery(SILS) port or other devices. However any prospective feasibility study demonstrating the safety of the procedure and functional outcomes (sphincter function, sexual function, QOF) are missing. This study investigates the feasibility, practicability, safety and subjective as well as functional outcome of transanal minimal invasive total mesentery excision for rectal cancer.

Inclusion Criteria:

• Biopsy-proven adenocarcinoma of the rectum
• Eligible to undergo conventional laparoscopic low anterior resection or transanal hybrid-laparoscopic low anterior resection with or without a temporary diverting stoma
• Node negative (N0), T1 (high risk features), T2 and T3 rectal cancer on pelvic MRI
• Closest distance between tumor edge and mesorectal fascia 5mm or more based on pelvic MRI
• Rectal cancer located 3-10 cm from the anal verge

Exclusion Criteria:

• Metastasis
• Obstructing rectal cancer
• Synchronous colon cancer
• T4 rectal cancer not treated preoperatively with full-course chemoradiation
• Pregnant or breast-feeding
• Receiving any other study agents
• Fecal incontinence
• History of prior colorectal cancer
• History of inflammatory bowel disease
• History of pelvic radiation
• BMI > 40
• Large uterine fibroids
• Uncontrolled intercurrent illness