title: Adjuvant chemotherapy for stage III colon cancer: does timing matter?
abstract: BACKGROUND
  Clinical trials commonly mandate that adjuvant chemotherapy for colon cancer should commence within 8 weeks (56 days) of surgery.
  
  
  OBJECTIVE
  We investigated the consequences of the timing of adjuvant chemotherapy for stage III colon cancer.
  
  
  METHODS
  This is a retrospective review of all patients with newly diagnosed stage III colon cancer who received adjuvant chemotherapy in 2 provincial centers in 1999 and 2000. The impact of time to adjuvant chemotherapy on overall survival and relapse-free survival was analyzed by the use of univariate and multivariate Cox modeling, adjusting for prognostic factors.
  
  
  RESULTS
  Three hundred forty-five subjects were included. Median time to adjuvant chemotherapy was 50 days (range, 20-242 days); in 111 (32.2%) patients, it was beyond 56 days. On univariate analysis, time >56 days was nonsignificantly associated with a hazard ratio of death of 1.31 (P = .12). Similar results were seen for relapse-free survival. Planned exploratory analysis suggests that the commencement of adjuvant chemotherapy up to 10 weeks postsurgery still confers a benefit.
  
  
  CONCLUSIONS
  Delaying adjuvant chemotherapy in stage III colon cancer beyond 8 to 10 weeks postsurgery appears to be associated with diminished benefit.
authors.affiliation: Department of Medical Oncology and Hematology, CancerCare Manitoba, Winnipeg, Manitoba, Canada. Piotr.czaykowski@cancercare.mb.ca
authors.forename: Piotr M
authors.initials: PM
authors.lastname: Czaykowski
authors.forename: Sharlene
authors.initials: S
authors.lastname: Gill
authors.forename: Hagen F
authors.initials: HF
authors.lastname: Kennecke
authors.forename: Vallerie L
authors.initials: VL
authors.lastname: Gordon
authors.forename: Donna
authors.initials: D
authors.lastname: Turner
mesh_terms: D000368:Aged; D001955:British Columbia; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome