Transanal total mesorectal excision for rectal cancer

The incidence of rectal cancer rises sharply with age. Symptoms include rectal bleeding and change in bowel habit, although the early stages may be asymptomatic.

The management of rectal cancer is described in NICE's guideline on colorectal cancer. The main treatment is surgery. It involves resecting the affected part of the rectum with anus preservation or, when anus preservation is not technically possible, colostomy formation. Adjunctive radiotherapy and chemotherapy may also be used to reduce the risk of local recurrence and prevent metastatic disease.

The aim of transanal total mesorectal excision is to improve the clinical outcome of rectal resection, and to reduce length of hospital stay and morbidity after surgery. It may enable proctectomy (removal of all or part of the rectum) that would be difficult by an open or laparoscopic approach. This could be in people with a narrow pelvis or high body mass index, or where the position of the tumour is low in the rectum.

Before surgery, the patient has bowel preparation and prophylactic antibiotics. Using general anaesthesia, and with the patient in the lithotomy position, standard abdominal laparoscopic mobilisation of the left colon and upper rectum is done. After inserting an operating platform into the anus, the lower rectum including the total mesorectum is mobilised. At the start of the transanal part of the procedure, a purse-string suture is put in to close the rectal lumen. This is followed by a full thickness rectotomy. After identifying the total mesorectal excision plane, the dissection progresses proximally until it connects with the dissection from above. The specimen can be removed through the transanal platform or, if the tumour is large, through the abdomen using a small incision. Anastomosis to connect the colon and the anus can be done using sutures (hand-sewn technique) or staples, and a temporary ileostomy is usually created. When anastomosis is not possible, a permanent stoma is created.