title: Tailored selection of the interval between neoadjuvant chemoradiotherapy and surgery for locally advanced rectal cancer: analysis based on the pathologic stage or chemoradiation response.
abstract: BACKGROUND
  The optimal interval between neoadjuvant chemoradiotherapy (CRT) and surgery has yet to be established. Additionally, it is unknown whether patients with different pathologic stages or chemoradiation responses should undergo different intervals between CRT and surgery. Therefore, the purpose of this study was to evaluate whether this interval has a differential effect on the oncologic outcome of patients with different chemoradiation responses or pathologic stages.
  
  
  METHODS
  We performed a retrospective study of 291 rectal cancer patients who were treated with preoperative chemoradiation and surgery between March 2004 and November 2012. All patients were separated into two groups according to a 7-week treatment interval. Overall survival (OS) and disease-free survival (DFS) were compared between patients undergoing intervals that were shorter and longer than 7 weeks in the entire group and in subgroups of ypT0-2N0, ypT3-4N0 and ypT0-4N+. The recurrence patterns were also analysed in all of the subgroups. Multivariate analysis was performed to explore the clinical factors that were significantly associated with DFS, local recurrence-free survival (LRFS) and distant metastasis-free survival among patients exhibiting ypT3-4N0 and ypT0-4N+.
  
  
  RESULTS
  For the ypT0-2N0 patients, the 5-year OS and DFS and the rates of local and distant recurrence were similar between the short and long interval groups. For the patients exhibiting ypT3-4N0, although no significant difference was found in OS or DFS between the short and long interval groups, the rate of local recurrence was higher in the long interval group, which was further confirmed by multivariate analysis. In the patients exhibiting ypT0-4N+, both OS and DFS were lower in the long interval group than in the short interval group. Furthermore, multivariate analysis indicated that the interval was significantly associated with DFS, especially LRFS.
  
  
  CONCLUSIONS
  The interval between CRT and surgery may exert a differential effect on the prognosis of patients exhibiting different pathologic stages or chemoradiation responses. Therefore, we strongly suggest tailoring the interval between CRT and surgery in locally advanced rectal cancer.
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Kai-yun
authors.initials: KY
authors.lastname: You
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Lu-ning
authors.initials: LN
authors.lastname: Zhang
authors.forename: Pei-rong
authors.initials: PR
authors.lastname: Ding
authors.forename: Wei-wei
authors.initials: WW
authors.lastname: Xiao
authors.forename: Bo
authors.initials: B
authors.lastname: Qiu
authors.forename: Hui
authors.initials: H
authors.lastname: Chang
authors.forename: Zhi-fan
authors.initials: ZF
authors.lastname: Zeng
authors.forename: Zhi-zhong
authors.initials: ZZ
authors.lastname: Pan
authors.forename: Yuan-hong
authors.initials: YH
authors.lastname: Gao
mesh_terms: D059186:Chemoradiotherapy, Adjuvant; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D057234:Preoperative Period; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery* / Q000628:therapy*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome