title: Body mass index and body surface area and their associations with outcomes in stage II and III colon cancer.
abstract: BACKGROUND
  Our study aims were to measure the associations between body mass index (BMI) and body surface area (BSA) with outcomes for stage II and III colon cancer and to evaluate if the effect of obesity is modified by disease stage and receipt of adjuvant therapy.
  
  
  METHODS
  Using a prospective cohort of stage II and III colon cancer patients who were referred between 2001 and 2005, we compared 3-year relapse-free survival (3-year RFS), 5-year cancer-specific survival (5-year CSS), and 5-year overall survival (5-year OS) rates among different BMI and BSA categories. Cox proportional-hazards models were constructed to explore the relationships between different body compositions and outcomes while adjusting for confounders.
  
  
  RESULTS
  Postoperative height and weight were used to classify 913 patients as normal weight (n = 424, BMI <25 kg/m(2)), overweight (n = 319, BMI 25-30 kg/m(2)), and obese (n = 170, BMI >30 kg/m(2)). Using Mosteller formula, 684 subjects had normal BSA (≤ 2.0 m(2)) and 229 had high BSA (>2.0 m(2)). Obese subjects experienced similar 3-year RFS (61.9 vs. 66.5 vs. 63.6 %, p = 0.51), 5-year CSS (65.6 vs. 72.4 vs. 68.0 %, p = 0.22), and 5-year OS (60.8 vs. 64.0 vs. 62.2 %, p = 0.69) when compared to overweight subjects and those with normal BMIs, respectively. Likewise, individuals with high BSA had similar outcomes as those with normal BSA (66.2 vs. 63.6 %, p = 0.64 for 3-year RFS, 70.3 vs. 68.6 %, p = 0.62 for 5-year CSS, and 64.5 vs. 61.9 %, p = 0.48 for 5-year OS). In Cox models, advanced age, male gender, stage III disease, and poor performance status correlated with inferior RFS, CSS, and OS, but BMI and BSA did not.
  
  
  CONCLUSIONS
  Obesity as measured by either BMI or BSA was not associated with differences in outcomes in stage II and III colon cancer.
authors.affiliation: Department of Medicine, University of British Columbia, 2775 Laurel Street, Vancouver, BC, Canada V5Z 1M9.
authors.forename: Sina
authors.initials: S
authors.lastname: Alipour
authors.forename: Hagen F
authors.initials: HF
authors.lastname: Kennecke
authors.forename: Ryan
authors.initials: R
authors.lastname: Woods
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Lim
authors.forename: Caroline
authors.initials: C
authors.lastname: Speers
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Brown
authors.forename: Sharlene
authors.initials: S
authors.lastname: Gill
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Renouf
authors.forename: Winson Y
authors.initials: WY
authors.lastname: Cheung
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001830:Body Surface Area; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000150:complications* / Q000401:mortality* / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D016016:Proportional Hazards Models; D016896:Treatment Outcome