Extended abdominoperineal excision vs. standard abdominoperineal excision in rectal cancer-a systematic overview

Background After introduction of total mesorectal excision (TME) as the gold standard for rectal cancer surgery, oncologic results appeared to be inferior for abdominoperineal excision (APE) as compared to anterior resection. This has been attributed to the technique of standard APE creating a waist at the level of the tumor-bearing segment. This systematic review investigates outcome of both standard and extended techniques of APE regarding inadvertent bowel perforation, circumferential margin (CRM) involvement, and local recurrence. Methods A literature search was performed to identify all articles reporting on APE after the introduction of TME using Medline, Ovid, and Embase. Extended APE was defined as operations that resected the levator ani muscle close to its origin. All other techniques were taken to be standard. Studies so identified were evaluated using a validated instrument for assessing nonrandomized studies. Rates for perforation, CRMinvolvement, and local recurrence were compared using chi-square statistics. Results In the extended group, 1,097 patients, and in the standard group, 4,147 patients could be pooled for statistical analysis. The rate of inadvertent bowel perforation and the rate of CRM involvement for extended vs. standard APE was 4.1% vs. 10.4% (relative risk reduction 60.6%, p=0.004) and 9.6% vs. 15.4% (relative risk reduction 37.7%, p=0.022), respectively. The local recurrence rate was 6.6% vs. 11.9% (relative risk reduction 44.5%, p<0.001) for the two groups. Conclusion This systematic review suggests that extended techniques of APE result in superior oncologic outcome as compared to standard techniques.