title: Impact of body mass index on prognostically relevant breast cancer tumor characteristics.
abstract: BACKGROUND
  This study analyzes the association of body mass index (BMI) and prognostically relevant breast cancer (BC) characteristics in a country that has been rather spared of the global obesity epidemic.
  
  
  METHODS
  Based on 20-year data (1999-2009, n = 1,414) of the prospective relational BC database of the University Hospital Basel, Switzerland, the associations between BMI, tumor size and stage, histological subtype, grading, hormonal receptor status, HER2 status and 'triple-negative' status were evaluated. Multivariate analysis considered BMI and patient's age.
  
  
  RESULTS
  The association between increasing BMI and the above-mentioned variables were as follows (results described in each case: Beta-coefficient or odds ratio, 95% confidence interval, p value): tumor size, (1) entire cohort: 0.03 (0.01-0.05), p < 0.001, (2) tumor found by self-palpation: 0.05 (0.03-0.07), p < 0.001, (3) tumor found by radiological examination: 0.03 (0-0.07), p = 0.044; advanced TNM stage: 1.16 (1.02-1.31), p = 0.022; histological subtype: 1.04 (0.89-1.22), p = 0.602; unfavorable grading: 1.11 (1.00-1.25), p = 0.057; positive estrogen receptor status: 0.95 (0.83-1.09), p = 0.459; positive HER2 status: 0.92 (0.74-1.15), p = 0.467; presence of a 'triple-negative' carcinoma: 1.19 (0.93-1.52), p = 0.165. Consideration of only postmenopausal BC patients (n = 1,063) did attenuate the results, but did not change the direction of the associations with BMI.
  
  
  CONCLUSIONS
  BMI was positively associated with TNM stage, grading and tumor size for tumors that were found by self-detection, as well as for those lesions detected by radiological breast examinations.
authors.affiliation: Division of Cancer Epidemiology and Prevention, Institute of Social and Preventive Medicine, University of Zurich, Basel, Switzerland.
authors.forename: Monika
authors.initials: M
authors.lastname: Eichholzer
authors.affiliation: Department of Obstetrics and Gynecology, Breast center, Hospital Grabs, Basel, Switzerland ; Breast Center, University Hospital Basel, Breast center, Hospital Grabs, Basel, Switzerland.
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Huang
authors.affiliation: Department of Obstetrics and Gynecology, Breast center, Hospital Grabs, Basel, Switzerland ; Breast Center, University Hospital Basel, Breast center, Hospital Grabs, Basel, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Modlasiak
authors.affiliation: Department of Gynecology and Obstetrics, Breast center, Hospital Grabs, Basel, Switzerland.
authors.forename: Seraina M
authors.initials: SM
authors.lastname: Schmid
authors.affiliation: Schötzau and Simmen Institute for Biomathematics, Basel, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schötzau
authors.affiliation: Division of Cancer Epidemiology and Prevention, Institute of Social and Preventive Medicine, University of Zurich, Basel, Switzerland.
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.affiliation: Department of Obstetrics and Gynecology, Breast center, Hospital Grabs, Basel, Switzerland ; Breast Center, University Hospital Basel, Breast center, Hospital Grabs, Basel, Switzerland ; Department of Gynecology and Obstetrics, Breast center, Cantonal Hospital Winterthur, Switzerland.
authors.forename: Uwe
authors.initials: U
authors.lastname: Güth
keywords: Body mass index; Breast cancer; Prognostic factors; Tumor detection; Tumor size