title: Effect of preoperative treatment strategies on the outcome of patients with clinical T3, non-metastasized rectal cancer: A comparison between Dutch and Canadian expert centers.
abstract: OBJECTIVE
  High-dose-rate brachytherapy (HDRBT) appears to be associated with less treatment-related toxicity compared with external beam radiotherapy in patients with rectal cancer. The present study compared the effect of preoperative treatment strategies on overall survival, cancer-specific deaths, and local recurrences between a Dutch and Canadian expert center with different preoperative treatment strategies.
  
  
  METHODS
  We included 145 Dutch and 141 Canadian patients with cT3, non-metastasized rectal cancer. All patients from Canada were preoperatively treated with HDRBT. The preoperative treatment strategy for Dutch patients consisted of either no preoperative treatment, short-course radiotherapy, or chemoradiotherapy. Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (CIs) comparing overall survival. We adjusted for age, cN stage, (y)pT stage, comorbidity, and type of surgery. Primary endpoint was overall survival. Secondary endpoints were cancer-specific deaths and local recurrences.
  
  
  RESULTS
  Five-year overall survival was 70.9% (95% CI 62.6%-77.7%) in Dutch patients compared with 86.9% (80.1%-91.6%) in Canadian patients, resulting in an adjusted HR of 0.70 (95% CI 0.39-1.26; p = 0.233). Of 145 Dutch patients, 6.9% (95% CI 2.8%-11.0%) had a local recurrence and 17.9% (95% CI 11.7%-24.2%) patients died of rectal cancer, compared with 4.3% (95% CI 0.9%-7.5%) local recurrences and 10.6% (95% CI 5.5%-15.7%) rectal cancer deaths out of 141 Canadian patients.
  
  
  CONCLUSIONS
  We did not detect statistically significant differences in overall survival between a Dutch and Canadian expert center with different treatment strategies. This finding needs to be further investigated in a randomized controlled trial.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Breugom
authors.affiliation: Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
authors.forename: T A
authors.initials: TA
authors.lastname: Vermeer
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: C B M
authors.initials: CB
authors.lastname: van den Broek
authors.affiliation: Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, Quebec, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Vuong
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands; Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Bastiaannet
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Montreal, Quebec, Canada; Department of Oncology, McGill University, Montreal, Quebec, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Azoulay
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: O M
authors.initials: OM
authors.lastname: Dekkers
authors.affiliation: Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, Quebec, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Niazi
authors.affiliation: Department of Radiotherapy, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
authors.forename: H A
authors.initials: HA
authors.lastname: van den Berg
authors.affiliation: Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
authors.forename: H J T
authors.initials: HJ
authors.lastname: Rutten
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: c.j.h.van_de_velde@lumc.nl.
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
mesh_terms: D000368:Aged; D003131:Combined Modality Therapy / Q000592:standards; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D017410:Practice Guidelines as Topic; D011300:Preoperative Care / Q000379:methods / Q000592:standards*; D011792:Quebec / Q000453:epidemiology; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends
keywords: Canada; External beam radiotherapy; High-dose-rate brachytherapy; Outcome; Rectal cancer; The Netherlands