title: Adjuvant chemotherapy for stage II colon cancer with poor prognostic features.
abstract: OBJECTIVE
  Adjuvant chemotherapy is typically considered for patients with stage II colon cancer characterized by poor prognostic features, including obstruction, perforation, emergent admission, T4 stage, resection of fewer than 12 lymph nodes, and poor histology. Despite frequent use, the survival advantage conferred on patients with stage II disease by chemotherapy is yet unproven. We sought to determine the overall survival benefit of chemotherapy among patients with stage II colon cancer having poor prognostic features.
  
  
  METHODS
  A total of 43,032 Medicare beneficiaries who underwent colectomy for stage II and III primary colon adenocarcinoma diagnosed from 1992 to 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) -Medicare database. χ(2) and two-way analysis of variance were used to assess differences in patient- and disease-related characteristics. Five-year overall survival was examined using Kaplan-Meier survival analysis and Cox proportional hazards regression with propensity score weighting.
  
  
  RESULTS
  Of the 24,847 patients with stage II cancer, 75% had one or more poor prognostic features. Adjuvant chemotherapy was received by 20% of patients with stage II disease and 57% of patients with stage III disease. After adjustment, 5-year survival benefit from chemotherapy was observed only for patients with stage III disease (hazard ratio[HR], 0.64; 95% CI, 0.60 to 0.67). No survival benefit was observed for patients with stage II cancer with no poor prognostic features (HR, 1.02; 95% CI, 0.84 to 1.25) or stage II cancer with any poor prognostic features (HR, 1.03; 95% CI, 0.94 to 1.13).
  
  
  CONCLUSIONS
  Among Medicare patients identified with stage II colon cancer, either with or without poor prognostic features, adjuvant chemotherapy did not substantially improve overall survival. This lack of benefit must be considered in treatment decisions for similar older adults with colon cancer.
authors.affiliation: University of Wisconsin, 600 Highland Ave, CSC 7375, Madison, WI 53792-7375, USA. eoconnor@uwhealth.org
authors.forename: Erin S
authors.initials: ES
authors.lastname: O'Connor
authors.forename: David Yu
authors.initials: DY
authors.lastname: Greenblatt
authors.forename: Noelle K
authors.initials: NK
authors.lastname: LoConte
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gangnon
authors.forename: Jinn-Ing
authors.initials: JI
authors.lastname: Liou
authors.forename: Charles P
authors.initials: CP
authors.lastname: Heise
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Smith
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D006278:Medicare; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018426:SEER Program; D015996:Survival Rate; D014481:United States / Q000453:epidemiology
chemical_list: D000970:Antineoplastic Agents