title: Accounting for individualized competing mortality risks in estimating postmenopausal breast cancer risk.
abstract: Accurate risk assessment is necessary for decision-making around breast cancer prevention. We aimed to develop a breast cancer prediction model for postmenopausal women that would take into account their individualized competing risk of non-breast cancer death.
  
  
  
  We included 73,066 women who completed the 2004 Nurses' Health Study (NHS) questionnaire (all ≥57 years) and followed participants until May 2014. We considered 17 breast cancer risk factors (health behaviors, demographics, family history, reproductive factors) and 7 risk factors for non-breast cancer death (comorbidities, functional dependency) and mammography use. We used competing risk regression to identify factors independently associated with breast cancer. We validated the final model by examining calibration (expected-to-observed ratio of breast cancer incidence, E/O) and discrimination (c-statistic) using 74,887 subjects from the Women's Health Initiative Extension Study (WHI-ES; all were ≥55 years and followed for 5 years).
  
  
  
  Within 5 years, 1.8 % of NHS participants were diagnosed with breast cancer (vs. 2.0 % in WHI-ES, p = 0.02), and 6.6 % experienced non-breast cancer death (vs. 5.2 % in WHI-ES, p < 0.001). Using a model selection procedure which incorporated the Akaike Information Criterion, c-statistic, statistical significance, and clinical judgement, our final model included 9 breast cancer risk factors, 5 comorbidities, functional dependency, and mammography use. The model's c-statistic was 0.61 (95 % CI [0.60-0.63]) in NHS and 0.57 (0.55-0.58) in WHI-ES. On average, our model under predicted breast cancer in WHI-ES (E/O 0.92 [0.88-0.97]).
  
  
  
  We developed a novel prediction model that factors in postmenopausal women's individualized competing risks of non-breast cancer death when estimating breast cancer risk.
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA. mschonbe@bidmc.harvard.edu.|Beth Israel Deaconess Medical Center, 1309 Beacon, Office 219, Brookline, MA, 02446, USA. mschonbe@bidmc.harvard.edu.
authors: Mara A
authors: 0000-0001-5162-5922
authors: MA
authors: Schonberg
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Vicky W
authors: VW
authors: Li
authors: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors: A Heather
authors: AH
authors: Eliassen
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Roger B
authors: RB
authors: Davis
authors: Division of Epidemiology, Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA.
authors: Andrea Z
authors: AZ
authors: LaCroix
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Ellen P
authors: EP
authors: McCarthy
authors: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors: Bernard A
authors: BA
authors: Rosner
authors: Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
authors: Rowan T
authors: RT
authors: Chlebowski
authors: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.|Department of Biostatistics and Epidemiology, University of Massachusetts, 713 North Pleasant Street, Amherst, MA, USA.
authors: Susan E
authors: SE
authors: Hankinson
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Edward R
authors: ER
authors: Marcantonio
authors: Division of General Medicine and Primary Care, Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Long H
authors: LH
authors: Ngo
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000401:mortality; D002423:Cause of Death; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D015233:Models, Statistical; D009026:Mortality; D011159:Population Surveillance; D017698:Postmenopause; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors
keywords: Breast cancer prediction; Competing risks; Older