title: Does rectal cancer shrinkage induced by preoperative radio(chemo)therapy increase the likelihood of anterior resection? A systematic review of randomised trials.
abstract: OBJECTIVE
  According to common conviction rectal tumour shrinkage after preoperative radio(chemo)therapy increases the likelihood of anterior resection (AR). In order to verify this belief, we performed a systematic review of randomised trials.
  
  
  METHODS
  We identified 10 randomised trials encompassing altogether 4596 patients in whom preoperative radio(chemo)therapy resulted in tumour shrinkage in the experimental arm as compared to the control arm.
  
  
  RESULTS
  Tumour shrinkage observed in the experimental groups did not result in a statistically significant higher ARs rate in any study when we performed an analysis of all the randomised cases. Subgroups of patients considered to be candidates for abdominoperineal resection before randomisation were identified in three trials. A statistically significantly higher rate of ARs was demonstrated in the experimental arm of the CAO/ARO/AIO 94 study. However, in that study, sphincter preservation was a secondary endpoint and some features of the trial may bias the estimation of the effect. The benefit of sphincter preservation was not confirmed by subgroup analyses performed in the Lyon R90-01 study and in the Polish study, which were originally designed to evaluate the sphincter preservation issue.
  
  
  CONCLUSIONS
  The body of evidence gathered from randomised trials does not support the concept of a beneficial effect of preoperative radiotherapy on the ARs rate.
authors.affiliation: Department of Radiotherapy, Maria Sklodowska-Cuie Memorial Cancer Centre, Warsaw, Poland. bujko@coi.waw.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Bujko
authors.forename: Lucyna
authors.initials: L
authors.lastname: Kepka
authors.forename: Wojciech
authors.initials: W
authors.lastname: Michalski
authors.forename: Marek P
authors.initials: MP
authors.lastname: Nowacki
mesh_terms: D002986:Clinical Trials as Topic; D003131:Combined Modality Therapy; D006801:Humans; D008953:Models, Anatomic; D018787:Radiation Oncology / Q000379:methods; D018714:Radiotherapy, Adjuvant; D016032:Randomized Controlled Trials as Topic; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D012007:Rectum / Q000473:pathology / Q000528:radiation effects; D016896:Treatment Outcome