Differences in Circumferential Resection Margin Involvement After Abdominoperineal Excision and Low Anterior Resection No Longer Significant

Objective: The aim of this study was to evaluate whether the abdominoperineal excision (APE) is associated with an increased risk of circumferential resection margin (CRM) involvement after rectal cancer surgery in comparison with low anterior resection (LAR). Background: The oncologic inferiority of the APE technique in comparison with LAR has been widely reported in literature. However, because of large evolvement in rectal cancer care, outcomes after APE may have improved since then. Methods: The population-based dataset of the Dutch Surgical Colorectal Audit was used selecting 5017 patients with primary rectal cancer undergoing surgery in 2010 to 2011. Propensity scores were calculated for the likelihood of performing an APE given relevant patient and tumor characteristics, and used in the multivariate analysis of CRM involvement. Results: The APE was associated with a slight, nonsignificant, increased risk of CRM involvement [ odds ratio (OR) = 1.33; confidence interval (CI) = 0.93-1.90]. Absolute percentages of CRM involvement were 8% and 12% after LAR and APE, respectively. In the subgroup analysis, advanced rectal tumors (cT3-4) were associated to a higher risk of CRM involvement after APE (OR = 1.61; CI = 1.05-1.90), whereas smaller tumors (cT1-2) were not (OR = 0.62; CI = 0.27-1.40). Conclusions: The results suggest that on a national level the APE procedure itself is not a strong predictor anymore for CRM involvement after rectal cancer surgery. However, in advanced tumors, results after APE are inferior to LAR.