title: Hormone receptor status of contralateral breast cancers: analysis of data from the US SEER population-based registries.
abstract: BACKGROUND
  Women diagnosed with breast cancer display higher propensity to develop second primary cancer in the contralateral breast (CBC). Identification of patients with increased risk of CBC and understanding relationships between hormone receptor (HR) statuses of the first and second breast cancers is desirable for endocrine-based prevention strategies.
  
  
  METHODS
  Using 1992-2012 data from 13 SEER registries, the risk of developing CBC was determined as ratio of observed and expected second breast cancers (SIR). Association between HR statuses was examined by exploratory data analysis and multivariable logistic regression.
  
  
  RESULTS
  Women with ER-positive and ER-negative breast cancers have increased risk of developing CBC with SIR values 2.09 (CI 95 = 1.97-2.21) and 2.40 (CI 95 = 2.18-2.63), respectively. ER statuses of the CBC are moderately positively associated. In metachronous CBC, most cases with ER-positive first cancers had ER-positive second breast cancers (81.6 %; CI 95 = 80.2-82.9 %); however, considerable proportion of cases with ER-negative first cancers had ER-positive second cancers (48.8 %; CI 95 = 46.2-51.4 %).
  
  
  CONCLUSIONS
  Some women with ER-negative breast cancers may benefit from endocrine-based prevention of ER-positive CBC.
authors: Integrated Cancer Research Center, School of Biology and Parker H. Petit Institute of Bioengineering and Biosciences, Georgia Institute of Technology, 310 Ferst DR, Atlanta, GA, 30329, USA. rmezencev3@gatech.edu.
authors: Roman
authors: R
authors: Mezencev
authors: The Faculty of Medicine and Faculty Hospital in Pilsen, Šikl's Department of Pathology, Charles University in Prague, Pilsen, Czech Republic.|Bioptická laboratoř, s.r.o., Pilsen, Czech Republic.
authors: Marián
authors: M
authors: Švajdler
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D015409:Mastectomy, Radical; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology / Q000378:metabolism* / Q000473:pathology; D011960:Receptors, Estrogen / Q000378:metabolism*; D012307:Risk Factors; D018426:SEER Program
chemical_list: D011960:Receptors, Estrogen
keywords: Bilateral breast cancer; Contralateral breast cancer; Estrogen receptor; Estrogen receptor-negative breast cancers; Metachronous breast cancer; Synchronous breast cancer