title: Optimal surgery time after preoperative chemoradiotherapy for locally advanced rectal cancers.
abstract: OBJECTIVE
  To evaluate the effect of the time interval between chemoradiotherapy (CRT) and surgery on CRT response and surgical outcomes.
  
  
  BACKGROUND
  Although preoperative CRT is a standard component of multimodal treatment for locally advanced rectal cancers, the optimal time for surgery after CRT has yet to be established. This study analyzed outcomes in 397 prospectively enrolled patients with locally advanced rectal cancer who underwent fractionated CRT involving 50.4 Gy radiotherapy followed by surgical resection between 4 and 8 weeks later.
  
  
  METHODS
  Patients were divided into 2 groups according to the time that elapsed between CRT and surgery: group A (28-41 day interval) and group B (42-56 day interval). CRT responses and surgical outcomes were analyzed.
  
  
  RESULTS
  Of the 397 patients, 217 (54.7%) were in group A and 180 (45.3%) in group B. The 2 groups were similar in terms of pretreatment characteristics other than a slight difference in mean age (A: 55.3 years vs. B: 57.5 years, P = 0.042). Analysis of CRT responses showed that the 2 groups were similar in terms of T-level downstaging rate (A: 47.5% vs. B: 44.4%, P = 0.548), volume reduction rate (A: 34.6% vs. B: 34.2%, P = 0.870) and complete response rate (A: 13.8% vs. B: 15.0%, P = 0.740). Analysis of surgical outcomes showed that the 2 groups were also similar in terms of sphincter-preservation rate (A: 83.9% vs. B: 82.2%, P = 0.688) and anastomosis-related complication rate (A: 5.5% vs. B: 3.9%, P = 0.453). The median follow-up period was 31 months (range, 5-63), and both groups showed similar local recurrence-free survival rates (P = 0.1165).
  
  
  CONCLUSIONS
  The present findings suggest that compared with a 4 to 6 week interval, delaying surgery for 6 to 8 weeks after completion of fractionated radiotherapy with concurrent chemotherapy does not improve CRT response or the sphincter-preservation rate, and does not decrease morbidity or local recurrence.
authors.affiliation: Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si, Korea.
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Hyo Seong
authors.initials: HS
authors.lastname: Choi
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Kyung Hae
authors.initials: KH
authors.lastname: Jung
authors.forename: Yong Sang
authors.initials: YS
authors.lastname: Hong
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Jae-Gahb
authors.initials: JG
authors.lastname: Park
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D000328:Adult; D000368:Aged; D017024:Chemotherapy, Adjuvant; D003082:Colectomy / Q000379:methods; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery* / Q000628:therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome