title: Established breast cancer risk factors by clinically important tumour characteristics.
abstract: Breast cancer is a morphologically and clinically heterogeneous disease; however, it is less clear how risk factors relate to tumour features. We evaluated risk factors by tumour characteristics (histopathologic type, grade, size, and nodal status) in a population-based case-control of 2386 breast cancers and 2502 controls in Poland. Use of a novel extension of the polytomous logistic regression permitted simultaneous modelling of multiple tumour characteristics. Late age at first full-term birth was associated with increased risk of large (> 2 cm) tumours (odds ratios (95% confidence intervals) 1.19 (1.07-1.33) for a 5-year increase in age), but not smaller tumours (P for heterogeneity adjusting for other tumour features (Phet) = 0.007). On the other hand, multiparity was associated with reduced risk for small tumours (0.76 (0.68-0.86) per additional birth; Phet = 0.004). Consideration of all tumour characteristics simultaneously revealed that current or recent use of combined hormone replacement therapy was associated with risk of small (2.29 (1.66-3.15)) and grade 1 (3.36 (2.22-5.08)) tumours (Phet = 0.05 for size and 0.0008 for grade 1 vs 3), rather than specific histopathologic types (Phet = 0.63 for ductal vs lobular). Finally, elevated body mass index was associated with larger tumour size among both pre- and postmenopausal women (Phet = 0.05 and 0.0001, respectively). None of these relationships were explained by hormone receptor status of the tumours. In conclusion, these data support distinctive risk factor relationships by tumour characteristics of prognostic relevance. These findings might be useful in developing targeted prevention efforts.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Rockville, MD 20852-7234, USA. montse@nih.gov
authors.forename: M
authors.initials: M
authors.lastname: García-Closas
authors.forename: L A
authors.initials: LA
authors.lastname: Brinton
authors.forename: J
authors.initials: J
authors.lastname: Lissowska
authors.forename: N
authors.initials: N
authors.lastname: Chatterjee
authors.forename: B
authors.initials: B
authors.lastname: Peplonska
authors.forename: W F
authors.initials: WF
authors.lastname: Anderson
authors.forename: N
authors.initials: N
authors.lastname: Szeszenia-Dabrowska
authors.forename: A
authors.initials: A
authors.lastname: Bardin-Mikolajczak
authors.forename: W
authors.initials: W
authors.lastname: Zatonski
authors.forename: A
authors.initials: A
authors.lastname: Blair
authors.forename: Z
authors.initials: Z
authors.lastname: Kalaylioglu
authors.forename: G
authors.initials: G
authors.lastname: Rymkiewicz
authors.forename: D
authors.initials: D
authors.lastname: Mazepa-Sikora
authors.forename: R
authors.initials: R
authors.lastname: Kordek
authors.forename: S
authors.initials: S
authors.lastname: Lukaszek
authors.forename: M E
authors.initials: ME
authors.lastname: Sherman
mesh_terms: D001943:Breast Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D015233:Models, Statistical; D009361:Neoplasm Invasiveness; D016017:Odds Ratio; D011044:Poland / Q000453:epidemiology; D011159:Population Surveillance; D011379:Prognosis; D012307:Risk Factors