title: Relationship between obesity and pathologic response to neoadjuvant chemotherapy among women with operable breast cancer.
abstract: OBJECTIVE
  To understand the mechanism through which obesity in breast cancer patients is associated with poorer outcome, we evaluated body mass index (BMI) and response to neoadjuvant chemotherapy (NC) in women with operable breast cancer.
  
  
  METHODS
  From May 1990 to July 2004, 1,169 patients were diagnosed with invasive breast cancer at M. D. Anderson Cancer Center and received NC before surgery. Patients were categorized as obese (BMI >or= 30 kg/m(2)), overweight (BMI of 25 to < 30 kg/m(2)), or normal/underweight (BMI < 25 kg/m(2)). Logistic regression was used to examine associations between BMI and pathologic complete response (pCR). Breast cancer-specific, progression-free, and overall survival times were examined using the Kaplan-Meier method and Cox proportional hazards regression analysis. All statistical tests were two-sided.
  
  
  RESULTS
  Median age was 50 years; 30% of patients were obese, 32% were overweight, and 38% were normal or underweight. In multivariate analysis, there was no significant difference in pCR for obese compared with normal weight patients (odds ratio [OR] = 0.78; 95% CI, 0.49 to 1.26). Overweight and the combination of overweight and obese patients were significantly less likely to have a pCR (OR = 0.59; 95% CI, 0.37 to 0.95; and OR = 0.67; 95% CI, 0.45 to 0.99, respectively). Obese patients were more likely to have hormone-negative tumors (P < .01), stage III tumors (P < .01), and worse overall survival (P = .006) at a median follow-up time of 4.1 years.
  
  
  CONCLUSIONS
  Higher BMI was associated with worse pCR to NC. In addition, its association with worse overall survival suggests that greater attention should be focused on this risk factor to optimize the care of breast cancer patients.
authors.affiliation: Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Litton
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gonzalez-Angulo
authors.forename: Carla L
authors.initials: CL
authors.lastname: Warneke
authors.forename: Aman U
authors.initials: AU
authors.lastname: Buzdar
authors.forename: Shu-Wan
authors.initials: SW
authors.lastname: Kau
authors.forename: Melissa
authors.initials: M
authors.lastname: Bondy
authors.forename: Somdat
authors.initials: S
authors.lastname: Mahabir
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Hortobagyi
authors.forename: Abenaa M
authors.initials: AM
authors.lastname: Brewster