title: Breast cancer risk factor associations differ for pure versus invasive carcinoma with an in situ component in case-control and case-case analyses.
abstract: OBJECTIVE
  Invasive ductal carcinoma (IDC) is diagnosed with or without a ductal carcinoma in situ (DCIS) component. Previous analyses have found significant differences in tumor characteristics between pure IDC lacking DCIS and mixed IDC with DCIS. We will test our hypothesis that pure IDC represents a form of breast cancer with etiology and risk factors distinct from mixed IDC/DCIS.
  
  
  METHODS
  We compared reproductive risk factors for breast cancer risk, as well as family and smoking history between 831 women with mixed IDC/DCIS (n = 650) or pure IDC (n = 181), and 1,620 controls, in the context of the Women's Circle of Health Study (WCHS), a case-control study of breast cancer in African-American and European-American women. Data on reproductive and lifestyle factors were collected during interviews, and tumor characteristics were abstracted from pathology reports. Case-control and case-case analyses were conducted using unconditional logistic regression.
  
  
  RESULTS
  Most risk factors were similarly associated with pure IDC and mixed IDC/DCIS. However, among postmenopausal women, risk of pure IDC was lower in women with body mass index (BMI) 25 to <30 [odds ratio (OR) 0.66; 95 % confidence interval (CI) 0.35-1.23] and BMI ≥ 30 (OR 0.33; 95 % CI 0.18-0.67) compared to women with BMI < 25, with no associations with mixed IDC/DCIS. In case-case analyses, women who breastfed up to 12 months (OR 0.55; 95 % CI 0.32-0.94) or longer (OR 0.47; 95 % CI 0.26-0.87) showed decreased odds of pure IDC than mixed IDC/DCIS compared to those who did not breastfeed.
  
  
  CONCLUSIONS
  Associations with some breast cancer risk factors differed between mixed IDC/DCIS and pure IDC, potentially suggesting differential developmental pathways. These findings, if confirmed in a larger study, will provide a better understanding of the developmental patterns of breast cancer and the influence of modifiable risk factors, which in turn could lead to better preventive measures for pure IDC, which have worse disease prognosis compared to mixed IDC/DCIS.
authors.affiliation: Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, 12 Capen Hall, Buffalo, NY, 14214, USA. mur@buffalo.edu.
authors.forename: Melanie
authors.initials: M
authors.lastname: Ruszczyk
authors.affiliation: Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Elm & Carlton Sts., Buffalo, NY, 14263, USA. gary.zirpoli@roswellpark.org.
authors.forename: Gary
authors.initials: G
authors.lastname: Zirpoli
authors.affiliation: Department of Surgical Oncology, Roswell Park Cancer Institute, Elm & Carlton Sts., Buffalo, NY, 14263, USA. shicha.kumar@roswellpark.org.
authors.forename: Shicha
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Population Science/Cancer Prevention and Control Program, Rutgers Cancer Institute of New Jersey, 195 Little Albany St., New Brunswick, NJ, 08903, USA. banderel@cinj.rutgers.edu.|Department of Epidemiology, Rutgers School of Public Health, 683 Hoes Ln W, Piscataway, NJ, 08854, USA. banderel@cinj.rutgers.edu.
authors.forename: Elisa V
authors.initials: EV
authors.lastname: Bandera
authors.affiliation: Department of Psychiatry, University of Pittsburgh Cancer Institute, 5150 Centre Ave., Pittsburgh, PA, 15232, USA. bovbjergdh@upmc.edu.
authors.forename: Dana H
authors.initials: DH
authors.lastname: Bovbjerg
authors.affiliation: Department of Oncology Sciences, Icahn School of Medicine at Mount Sinai, 1428 Madison Ave., New York, NY, 10029, USA. lina.jandorf@mssn.edu.
authors.forename: Lina
authors.initials: L
authors.lastname: Jandorf
authors.affiliation: Department of Pathology, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY, 14263, USA. thaer.khoury@roswellpark.org.
authors.forename: Thaer
authors.initials: T
authors.lastname: Khoury
authors.affiliation: Department of Pathology, University of Texas, Southwestern Medical Center, 5325 Harry Hines Blvd., Dallas, TX, 75390, USA. helena.hwang@utsouthwestern.edu.
authors.forename: Helena
authors.initials: H
authors.lastname: Hwang
authors.affiliation: Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Elm & Carlton Sts., Buffalo, NY, 14263, USA. gregory.ciupak@roswellpark.org.
authors.forename: Gregory
authors.initials: G
authors.lastname: Ciupak
authors.affiliation: New Jersey State Cancer Registry, New Jersey Department of Health, 140 East Front Street, Trenton, NJ, 08625, USA. karen.pawlish@doh.state.nj.us.
authors.forename: Karen
authors.initials: K
authors.lastname: Pawlish
authors.affiliation: Department of Cell, Development and Cancer Biology, Oregon Health Sciences University, 3181 SW Sam Jackson Pkwy, Portland, OR, 97239, USA. schedin@ohsu.edu.
authors.forename: Pepper
authors.initials: P
authors.lastname: Schedin
authors.affiliation: Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, 12 Capen Hall, Buffalo, NY, 14214, USA. pmwelch@buffalo.edu.
authors.forename: Patricia
authors.initials: P
authors.lastname: Masso-Welch
authors.affiliation: Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Elm & Carlton Sts., Buffalo, NY, 14263, USA. christine.ambrosone@roswellpark.org.
authors.forename: Christine B
authors.initials: CB
authors.lastname: Ambrosone
authors.affiliation: Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Elm & Carlton Sts., Buffalo, NY, 14263, USA. chi-chen.hong@roswellpark.org.
authors.forename: Chi-Chen
authors.initials: CC
authors.lastname: Hong
mesh_terms: D000328:Adult; D001942:Breast Feeding / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000453:epidemiology* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D050177:Overweight / Q000453:epidemiology; D017584:Reproductive History; D012307:Risk Factors
keywords: Breast cancer; Cancer etiology; Cancer pathology; Ductal carcinoma in situ component; Risk factors