Patients

This was a retrospective study, and informed consent was obtained from all patients before surgery. Between September 2011 and March 2014, an extralevator APR in the prone position was performed on 13 patients with rectal cancer, and a conventional APR in the lithotomy position was carried out on 26 such patients. Eligibility criteria included a pathologically-confirmed rectal adenocarcinoma and patients who had undergone an APR (extralevator or conventional) with a curative intent. At our institution, the indication for using an APR for the treatment of patients with rectal cancer is a tumor that is still invading the anal sphincter muscle in the image finding after preoperative chemoradiotherapy or anal incontinence caused by decreased sphincter function even though the tumor is located at the mid rectum. Especially, when the tumor is located at the level of the anorectal ring or has invaded more deeply adjacent muscles such as the puborectalis muscle and the external sphincter muscle, an extralevator APR, instead of a conventional APR, is recommended for achieving a free CRM. Preoperative evaluations included physical examination, colonoscopy, transrectal ultrasonography, pelvic magnetic resonance imaging, and computed tomography of the abdomen, pelvis, and chest. Except those who refused it, most patients underwent preoperative long-course chemoradiotherapy as part of a multimodality treatment course. The details of the chemotherapy regimens and the radiation treatment schedules are described elsewhere [12].