title: Oncological superiority of extralevator abdominoperineal resection over conventional abdominoperineal resection: a meta-analysis.
abstract: OBJECTIVE
  The oncological superiority, i.e., lower circumferential resection margin (CRM) involvement, lower intraoperative perforation (IOP), and local recurrence (LR) rates, of extralevator abdominoperineal resection (EAPR) over conventional abdominoperineal resection (APR) for rectal cancer is inconclusive. This meta-analysis systematically compared the rates of CRM involvement, IOP, and LR of rectal cancer patients treated by EAPR and APR, respectively.
  
  
  METHODS
  An electronic literature search of MEDLINE, EMBASE, and Cochrane Library through May 2013 was performed by two investigators independently to identify studies evaluating the CRM involvement, IOP, and LR rates of EAPR and APR, and search results were cross-checked to reach a consensus. Data was extracted accordingly. A Mantel-Haenszel random effects model was used to calculate the odds ratio (OR) with 95 % confidence intervals (95 % CI).
  
  
  RESULTS
  Six studies with a total of 881 patients were included. Meta-analysis of CRM involvement and IOP data from all six studies demonstrated significant lower CRM involvement (OR, 0.36; 95%CI, 0.23-0.58; P < 0.0001) and IOP (OR, 0.31; 95%CI, 0.12-0.80; P = 0.02) rates of EAPR. Data from four studies also showed that EAPR was associated with a lower LR rate than APR (OR, 0.27; 95%CI, 0.08-0.95; P = 0.04). No differences of between-study heterogeneity or publication bias were seen in any of the meta-analyses.
  
  
  CONCLUSIONS
  Extralevator abdominoperineal resection could achieve better CRM involvement outcome and lower IOP and LR rates, demonstrating an oncological superiority over conventional abdominoperineal resection.
authors.affiliation: Department of Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Rd, Shanghai, 20002, People's Republic of China.
authors.forename: Ao
authors.initials: A
authors.lastname: Huang
authors.forename: Hongchao
authors.initials: H
authors.lastname: Zhao
authors.forename: Tianlong
authors.initials: T
authors.lastname: Ling
authors.forename: Yingjun
authors.initials: Y
authors.lastname: Quan
authors.forename: Minhua
authors.initials: M
authors.lastname: Zheng
authors.forename: Bo
authors.initials: B
authors.lastname: Feng
mesh_terms: D000005:Abdomen / Q000601:surgery*; D059186:Chemoradiotherapy, Adjuvant; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local; D010502:Perineum / Q000601:surgery*; D012004:Rectal Neoplasms / Q000601:surgery* / Q000628:therapy; D012007:Rectum / Q000601:surgery*; D016896:Treatment Outcome