Abstract: Objective To explore the safety and feasibility of pure transanal total mesorectal excision (pure-TaTME)combination with intersphincteric resection (ISR) for ultra-low rectal cancer.Methods The patient with ultra-low rectal cancer, who had been treated with pure-TaTME and ISR, was screened carefully by colonoscopy, endorectal ultrasound and MRI examination. A purse suture closure of the rectal lumen at the level of tumor's inferior edge was done transanally. The cut-line was made vertically to the anal canal at the level of dentate line, and further ISR procedure was performed upright into the pelvic floor.Then pure-TaTME was performed. The specimen was pulled down transanally and removed. A colo-anal anastomosis was made by use of circle stapler. Results The operation time was 350 min and the volume of blood loss was 200 mL. The length of the specimen was about 18 cm with intact mesorectum. The distal resection margin was 1.0 cm below the inferior edge of tumor.The circumferential resection margin (CRM) was negative.The pathological cancer staging was T₁N₀M₀. Totally 32 lymph nodes had been retrieved without positive node. The postoperative recovery of patient was good without any evidence of infection and anastomotic leakage. Defecation function was acceptable and no tumor relapse was detected after a follow-up of 24 months.Conclusion The operation of pure-TaTME combined with ISR is safe, which provides a feasible option for the surgical treatment of the low or ultra-low rectal cancer. The long-term outcome need to be identified by further clinical study.

Key words: ultra-low rectal cancer, transanal total mesorectal excision (TaTME), pure transanal total mesorectal excision (pure-TaTME), intersphincteric resection (ISR)