A Randomized, Controlled, Multicenter Trial to Evaluate the Safety and Efficacy of Cylindrical Abdominoperineal Resection in the Treatment of Advanced Very Low Rectal Cancer

Abdominoperineal resection (APR) is still a common operation in patients with tumours less than 6 cm from the anal verge. The perineal phase of APR is a difficult part of the operation, often done with the patient in the supine position.The risk of inadvertent bowel perforation is high, the resulting specimen frequently has a waist at the lower border of the mesorectum, and the circumferential resection margin (CRM) is often close to the rectal muscle tube. The cylindrical APR may be performed via an extended posterior perineal approach, that aims to create a more cylindrical specimen without a waist. The potential benefit of this technique is a reduction in the risk of bowel perforation and tumour involvement of the CRM, and thus in the risk of local recurrence.

Perineal wounds in patients following APR are at considerable risk for infection, dehiscence and delayed healing when closed primarily. This can be further increased in patients who have received neoadjuvant chemoradiation therapy. The adoption of extended resection, such as the cylindrical APR, may cause additional risks. The use of acellular biomaterials, including human acellular dermal matrix (HADM) has drawn great interest for the complex abdominal wall reconstruction.

The purpose of this study is to determine whether cylindrical abdominoperineal resection is effective in the treatment of advanced very low rectal cancer, and to determine the initial results of pelvic reconstruction using human acellular dermal matrix after cylindrical abdominoperineal resection.