title: Survival after Abdominoperineal and Sphincter-Preserving Resection in Nonmetastatic Rectal Cancer: A Population-Based Time-Trend and Propensity Score-Matched SEER Analysis.
abstract: Background.Abdominoperineal resection (APR) has been associated with impaired survival in nonmetastatic rectal cancer patients. It is unclear whether this adverse outcome is due to the surgical procedure itself or is a consequence of tumor-related characteristics.Study Design.Patients were identified from the Surveillance, Epidemiology, and End Results database. The impact of APR compared to coloanal anastomosis (CAA) on survival was assessed by Cox regression and propensity-score matching.Results.In 36,488 patients with rectal cancer resection, the APR rate declined from 31.8% in 1998 to 19.2% in 2011, with a significant trend change in 2004 at 21.6% (P< 0.001). To minimize a potential time-trend bias, survival analysis was limited to patients diagnosed after 2004. APR was associated with an increased risk of cancer-specific mortality after unadjusted analysis (HR = 1.61, 95% CI: 1.28-2.03,P< 0.01) and multivariable adjustment (HR = 1.39, 95% CI: 1.10-1.76,P< 0.01). After optimal adjustment of highly biased patient characteristics by propensity-score matching, APR was not identified as a risk factor for cancer-specific mortality (HR = 0.85, 95% CI: 0.56-1.29,P= 0.456).Conclusions.The current propensity score-adjusted analysis provides evidence that worse oncological outcomes in patients undergoing APR compared to CAA are caused by different patient characteristics and not by the surgical procedure itself.
authors.affiliation: Department of Surgery, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland; Institute of Medical Biometry and Informatics, University of Heidelberg, 69120 Heidelberg, Germany.
authors.forename: Rene
authors.initials: R
authors.lastname: Warschkow
authors.affiliation: Department of Surgery, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland; Department of Surgery, Hospital of Thun, 3600 Thun, Switzerland.
authors.forename: Sabrina M
authors.initials: SM
authors.lastname: Ebinger
authors.affiliation: Department of Surgery, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland.
authors.forename: Walter
authors.initials: W
authors.lastname: Brunner
authors.affiliation: Department of Surgery, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland.
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Schmied
authors.affiliation: Department of Surgery, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland; Department of Surgery, Universitätsmedizin Mannheim, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany.
authors.forename: Lukas
authors.identifier: 0000-0001-5413-132X
authors.initials: L
authors.lastname: Marti