Evidence of the Oncologic Superiority of Cylindrical Abdominoperineal Excision for Low Rectal Cancer

Abdominoperineal excision (APE) of the rectum and anus for rectal cancer continues to have greater local recurrence and poorer survival than that seen following anterior resection. Changing to an extended prone perineal dissection results in a more cylindrical specimen and should improve outcomes. One hundred twenty-eight specimens from patients who underwent APE that was performed for potentially curable primary rectal adenocarcinoma were dissected according to standard protocol in Leeds and Stockholm between 1997 and 2007 and were studied. Tissue morphometry was performed on the cross sectional photographs of 93 patient cases. The cylindrical technique removed more tissue in the distal rectum and in all slices that contained tumor compared with the standard operation (both P < .0001). Greater distance was observed from the muscularis propria or internal sphincter to the anterior, posterior, and lateral resection margins (all P < .0001). This was associated with lower circumferential resection margin (CRM) involvement (14.8% v 40.6%; P = .013) and intraoperative perforations (3.7% v 22.8%; P = .0255). An increase in the amount of tissue removed in the distal rectum (P < .0001) was demonstrated by a single surgeon who changed from the standard to the cylindrical technique during the study period; the change was associated with a reduction in CRM positivity (from 36.2% to 12.5%) and in perforations (from 12.8% to 0.0%). Cylindrical APE performed in the prone position for low rectal cancer removes more tissue around the tumor that leads to a reduction in CRM involvement and intraoperative perforations, which should reduce local disease recurrence. The cylindrical technique has the potential to improve patient outcomes substantially if appropriate surgical education programs are developed.