title: Mammographic breast density is associated with the development of contralateral breast cancer.
abstract: Women with dense mammographic breast density (BD) have a 2-fold increased risk of developing primary breast cancer (BC). The authors hypothesized that dense mammographic BD also is associated with an increased risk of developing contralateral breast cancer (CBC).
  
  
  
  Among female patients treated at The University of Texas MD Anderson Cancer Center for sporadic, AJCC stage I to stage III BC between January 1997 and December 2012, the authors identified patients who had developed metachronous CBC (cases) and selected 1:2 matched controls who did not develop CBC using incidence density sampling, matched on attainted age, year of diagnosis, and hormone receptor status of the first BC. Mammographic BD, assessed at the time of first BC diagnosis, was categorized as "nondense" (American College of Radiology breast categories of fatty or scattered density) or "dense" (American College of Radiology categories of heterogeneously dense or extremely dense). Multivariable conditional logistic regression models were used for statistical analysis.
  
  
  
  A total of 229 cases and 451 controls were evaluated. Among the cases, approximately 39.3% had nondense breast tissue and 60.7% had dense breast tissue. Among controls, approximately 48.3% had nondense breast tissue and 51.7% had dense breast tissue. After adjustment for potential prognostic risk factors for BC, the odds of developing CBC were found to be significantly higher for patients with dense breasts (odds ratio, 1.80; 95% confidence interval, 1.22-2.64 [P<.01]) than for those with nondense breasts. Patients who received chemotherapy or endocrine therapy were less likely to develop CBC.
  
  
  
  In women with primary BC, mammographic BD appears to be a risk factor for the development of CBC. Cancer 2017;123:1935-1940. © 2017 American Cancer Society.
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Akshara
authors.initials: A
authors.lastname: Raghavendra
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.|Department of Biostatistics, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Arup K
authors.initials: AK
authors.lastname: Sinha
authors.affiliation: Division of Diagnostic Imaging, Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Huong T
authors.initials: HT
authors.lastname: Le-Petross
authors.affiliation: Division of Diagnostic Imaging, Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Naveen
authors.initials: N
authors.lastname: Garg
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Limin
authors.initials: L
authors.lastname: Hsu
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Modesto
authors.initials: M
authors.lastname: Patangan
authors.affiliation: Division of Cancer Medicine, Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Therese Bartholomew
authors.initials: TB
authors.lastname: Bevers
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Arun
authors.initials: A
authors.lastname: Banu
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Debu
authors.initials: D
authors.lastname: Tripathy
authors.affiliation: Division of Cancer Medicine, Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bedrosian
authors.affiliation: Division of Cancer Medicine, Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Barcenas
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology*; D000071060:Breast Density; D001943:Breast Neoplasms / Q000453:epidemiology*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology*; D018275:Carcinoma, Lobular / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors
keywords: contralateral breast cancer; dense; mammographic breast density; nondense