title: Complete Pathological Response After Neoadjuvant Long-Course Chemoradiotherapy for Rectal Cancer and Its Relationship to the Degree of T3 Mesorectal Invasion.
abstract: BACKGROUND
  Many studies have shown significantly improved outcomes (reduced local recurrence and improved overall survival) for patients achieving a complete pathological response from neoadjuvant chemoradiotherapy.
  
  
  OBJECTIVE
  This study aimed to document the complete pathological response rate and outcomes in patients receiving preoperative long-course chemoradiotherapy stratified for the extent of T3 mesorectal invasion measured on preoperative imaging.
  
  
  METHODS
  This is a retrospective study of prospectively collected data, of patients with rectal cancer in the Cabrini Monash University Department of Surgery colorectal neoplasia database, incorporating data from Cabrini Hospital and The Alfred Hospital, identifying patients entered between January 2010 and June 2014.
  
  
  METHODS
  One hundred eighteen patients with T3 rectal cancer met the selection criteria for the study; 26 achieved complete pathological response (22%).
  
  
  METHODS
  Outcomes in terms of complete pathological response and oncological outcomes such as disease-free and overall survival were analyzed.
  
  
  RESULTS
  Patients with complete pathological response had significantly less preoperative invasion than those with no complete pathological response (p < 0.001). Depth of invasion was the only variable associated with complete pathological response (p < 0.002), and the likelihood of complete pathological response decreased by 35% for every millimeter of invasion. Complete pathological response was associated with increased disease-free survival (p = 0.018) and a lower risk of cancer progression (p = 0.046). Depth of invasion was associated with an increased risk of death after surgery; HR increased by 1.07 (95% CI, 1.00-1.15) for each 1-mm increase in invasion.
  
  
  CONCLUSIONS
  This was a retrospective study with the usual limitations, although these were minimized through the use of a clinician-driven prospective database.
  
  
  CONCLUSIONS
  The smaller the degree of T3 invasion, the higher the chance of achieving complete pathological response (up to 35%), which is associated with improved disease-free and overall survival. A higher complete pathological response rate is observed in early T3 disease in comparison with more extensive T3 invasion.
authors.affiliation: 1 Cabrini Monash University Department of Surgery, Cabrini Hospital, Malvern, Victoria, Australia 2 Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Victoria, Australia 3 William Buckland Radiotherapy Centre, The Alfred Hospital, Department of Surgery, Monash University Central Clinical School, Melbourne, Victoria, Australia 4 Monash Department of Clinical Epidemiology, Cabrini Hospital, Malvern, Victoria, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Wilkins
authors.forename: Andrew
authors.initials: A
authors.lastname: Haydon
authors.forename: Ian
authors.initials: I
authors.lastname: Porter
authors.forename: Karen
authors.initials: K
authors.lastname: Oliva
authors.forename: Margaret
authors.initials: M
authors.lastname: Staples
authors.forename: Peter
authors.initials: P
authors.lastname: Carne
authors.forename: Paul
authors.initials: P
authors.lastname: McMurrick
authors.forename: Stephen
authors.initials: S
authors.lastname: Bell
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011300:Preoperative Care; D057234:Preoperative Period; D012004:Rectal Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000473:pathology*; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome