title: Short-term preoperative radiotherapy results in down-staging of rectal cancer: a study of 1316 patients.
abstract: OBJECTIVE
  This study was undertaken to investigate down-staging effects after short-term, high-fractionated preoperative radiotherapy.
  
  
  METHODS
  The relationships between preoperative radiotherapy 25-25.5 Gy given over 5-7 days and clinical variables (sex, age, tumour level, metastatic disease, and tumour size) and the risk of lymph node metastases were examined in 1316 patients with rectal adenocarcinoma by uni-, and multivariate analyses.
  
  
  RESULTS
  Irradiated specimens contained smaller tumours (P < 0.00001) and nodal metastases were less common (P < 0.001). In a logistic regression model, tumour size in cm was positively related to the risk for nodal spread (odds ratio, OR = 1.14, 95% confidence limits, CL, of OR 1.08-1.22). In the same model, radiotherapy decreased the risk for nodal involvement (OR 0.73, 95% CL 0.58-0.92. This risk was particularly reduced when the time interval between start of radiotherapy and surgery equalled 10 days or more.
  
  
  CONCLUSIONS
  These results demonstrate a down-staging effect by a short course of preoperative radiotherapy which should be considered in the interpretation of radiotherapy trials and in the recruitment of patients for further postoperative adjuvant treatment.
authors.affiliation: Department of Surgery, University Hospital, Akademiska sjukhuset, Uppsala, Sweden.
authors.forename: W
authors.initials: W
authors.lastname: Graf
authors.forename: M
authors.initials: M
authors.lastname: Dahlberg
authors.forename: M M
authors.initials: MM
authors.lastname: Osman
authors.forename: L
authors.initials: L
authors.lastname: Holmberg
authors.forename: L
authors.initials: L
authors.lastname: Pählman
authors.forename: B
authors.initials: B
authors.lastname: Glimelius
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery