title: Clinical prediction of pathological complete response after preoperative chemoradiotherapy for rectal cancer.
abstract: BACKGROUND
  The clinical pretreatment factors that accurately predict response to chemoradiation in rectal cancer are not currently known.
  
  
  OBJECTIVE
  The aim of this study is to evaluate the clinical factors associated with a pathological complete response after preoperative chemoradiotherapy for rectal cancer.
  
  
  METHODS
  This study is a retrospective review of prospectively collected data.
  
  
  METHODS
  This study was conducted at a tertiary care hospital/referral center in South Korea.
  
  
  METHODS
  From December 2000 to September 2011, a total of 391 consecutive patients with rectal cancer who underwent neoadjuvant chemoradiotherapy followed by radical surgery were identified. The treatment consisted of concurrent chemoradiation, which included preoperative 5-fluorouracil-based chemotherapy and pelvic radiation (median, 5040 cGy); this was followed 8 weeks later (median, 57 days) by surgery with curative intent.
  
  
  METHODS
  The primary outcome measured was the clinicopathological comparison between pathological complete response (n = 57, 14.6%) and non-pathological complete response (n = 334, 85.4%) groups.
  
  
  RESULTS
  The pathological complete response groups had a higher percentage of noncircumferential tumors, nonmacroscopic ulceration, well differentiation, small tumor diameter, early clinical T stage, early clinical N stage, or low levels of pretreatment CEA than the non-pathological complete response group. In multivariate regression analysis, independent predictors of a higher pathological complete response rate were noncircumferentiality (p = 0.007; OR, 3.214), nonmacroscopic ulceration (p = 0.002; OR, 6.702), and low pretreatment CEA level (p = 0.004; OR, 2.656). Significant differences in the pathological complete response rate existed among the 4 risk stratification groups (p < 0.001). For the prediction of pathological complete response by the clinical risk score model, the sensitivity was 64.1% and the specificity was 73.7% (area under the curve, 0.706; p < 0.001).
  
  
  CONCLUSIONS
  This study was limited because it was a single-institution study with a small sample size.
  
  
  CONCLUSIONS
  Pretreatment clinical variables, including tumor circumferentiality, macroscopic ulceration, and CEA level, may be important determinants in achieving a pathological complete response.
authors: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jung Wook
authors: JW
authors: Huh
authors: Hyeong Rok
authors: HR
authors: Kim
authors: Young Jin
authors: YJ
authors: Kim
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000379:methods*; D003131:Combined Modality Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D057234:Preoperative Period; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D056910:Republic of Korea; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome