title: Evidence for cure by adjuvant therapy in colon cancer: observations based on individual patient data from 20,898 patients on 18 randomized trials.
abstract: OBJECTIVE
  Limited data are available on the time course of treatment failures (recurrence and/or death), the nature and duration of adjuvant treatment benefit, and long-term recurrence rates in patients with resected stage II and III colon cancer.
  
  
  METHODS
  The data set assembled by the Adjuvant Colon Cancer Endpoints Group, a collection of individual patient data from 18 trials and more than 20,800 patients testing fluorouracil-based adjuvant therapy in patients with stage II or III colon cancer, was analyzed.
  
  
  RESULTS
  A significant overall survival (OS) benefit of adjuvant therapy was consistent over the 8-year follow-up period. The risk of recurrence in patients treated with adjuvant chemotherapy never exceeds that of control patients, signifying that adjuvant therapy cures some patients, as opposed to delaying recurrence. After 5 years, recurrence rates were less than 1.5% per year, and after 8 years, they were less than 0.5% per year. Significant disease-free survival (DFS) benefit from adjuvant chemotherapy was observed in the first 2 years. After 2 years, DFS rates in treated and control patients were not significantly different, and after 4 years, no trend toward benefit was demonstrated. This benefit was primarily driven by patients with stage III disease.
  
  
  CONCLUSIONS
  Adjuvant chemotherapy provides significant DFS benefit, primarily by reducing the recurrence rate, within the first 2 years of adjuvant therapy with some benefit in years 3 to 4, translating into long-term OS benefit. This reflects the curative role of chemotherapy in the adjuvant setting. After 5 years, recurrence rates in patients treated on clinical trials are low, and after 8 years, they are minimal; thus, long-term follow-up for recurrence is of little value.
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA. sargent.daniel@mayo.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Sargent
authors.forename: Alberto
authors.initials: A
authors.lastname: Sobrero
authors.forename: Axel
authors.initials: A
authors.lastname: Grothey
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Connell
authors.forename: Marc
authors.initials: M
authors.lastname: Buyse
authors.forename: Thierry
authors.initials: T
authors.lastname: Andre
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Erin
authors.initials: E
authors.lastname: Green
authors.forename: Roberto
authors.initials: R
authors.lastname: Labianca
authors.forename: Chris
authors.initials: C
authors.lastname: O'Callaghan
authors.forename: Jean Francois
authors.initials: JF
authors.lastname: Seitz
authors.forename: Guido
authors.initials: G
authors.lastname: Francini
authors.forename: Daniel
authors.initials: D
authors.lastname: Haller
authors.forename: Greg
authors.initials: G
authors.lastname: Yothers
authors.forename: Richard
authors.initials: R
authors.lastname: Goldberg
authors.forename: Aimery
authors.initials: A
authors.lastname: de Gramont
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005472:Fluorouracil / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil