title: Brain Metastases in Newly Diagnosed Breast Cancer: A Population-Based Study.
abstract: OBJECTIVE
  Population-based estimates of the incidence and prognosis of brain metastases at diagnosis of breast cancer are lacking.
  
  
  OBJECTIVE
  To characterize the incidence proportions and median survivals of patients with breast cancer and brain metastases at the time of cancer diagnosis.
  
  
  METHODS
  Patients with breast cancer and brain metastases at the time of diagnosis were identified using the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute. Data were stratified by subtype, age, sex, and race. Multivariable logistic and Cox regression were performed to identify predictors of the presence of brain metastases at diagnosis and factors associated with all-cause mortality, respectively. For incidence, we identified a population-based sample of 238 726 adult patients diagnosed as having invasive breast cancer between 2010 and 2013 for whom the presence or absence of brain metastases at diagnosis was known. Patients diagnosed at autopsy or with an unknown follow-up were excluded from the survival analysis, leaving 231 684 patients in this cohort.
  
  
  METHODS
  Incidence proportion and median survival of patients with brain metastases and newly diagnosed breast cancer.
  
  
  RESULTS
  We identified 968 patients with brain metastases at the time of diagnosis of breast cancer, representing 0.41% of the entire cohort and 7.56% of the subset with metastatic disease to any site. A total of 57 were 18 to 40 years old, 423 were 41 to 60 years old, 425 were 61-80 years old, and 63 were older than 80 years. Ten were male and 958 were female. Incidence proportions were highest among patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive (1.1% among entire cohort, 11.5% among patients with metastatic disease to any distant site) and triple-negative (0.7% among entire cohort, 11.4% among patients with metastatic disease to any distant site) subtypes. Median survival among the entire cohort with brain metastases was 10.0 months. Patients with HR-positive HER2-positive subtype displayed the longest median survival (21.0 months); patients with triple-negative subtype had the shortest median survival (6.0 months).
  
  
  CONCLUSIONS
  The findings of this study provides population-based estimates of the incidence and prognosis for patients with brain metastases at time of diagnosis of breast cancer. The findings lend support to consideration of screening imaging of the brain for patients with HER2-positive or triple-negative subtypes and extracranial metastases.
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Martin
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Cagney
authors.affiliation: Department of Biostatistics, Harvard T. H. Chan School of Public Health, and Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Catalano
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Warren
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Bellon
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Rinaa S
authors.initials: RS
authors.lastname: Punglia
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.|School of Public Health, Yale University, New Haven, Connecticut.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Claus
authors.affiliation: Department of Neuro-Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Eudocia Q
authors.initials: EQ
authors.lastname: Lee
authors.affiliation: Department of Neuro-Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Patrick Y
authors.initials: PY
authors.lastname: Wen
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Daphne A
authors.initials: DA
authors.lastname: Haas-Kogan
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Alexander
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Nancy U
authors.initials: NU
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ayal A
authors.initials: AA
authors.lastname: Aizer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000556:secondary*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human