title: Occurrence and outcome of de novo metastatic breast cancer by subtype in a large, diverse population.
abstract: To examine the occurrence and outcomes of de novo metastatic (Stage IV) breast cancer, particularly with respect to tumor HER2 expression.
  
  
  
  We studied all 6,268 de novo metastatic breast cancer cases diagnosed from 1 January 2005 to 31 December 2011 and reported to the California Cancer Registry. Molecular subtypes were classified according to HER2 and hormone receptor (HR, including estrogen and/or progesterone receptor) expression. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) of Stage IV versus Stage I-III breast cancer; Cox proportional hazards regression was used to assess relative hazard (RH) of mortality.
  
  
  
  Five percent of invasive breast cancer was metastatic at diagnosis. Compared to patients with earlier stage disease, patients with de novo metastatic disease were significantly more likely to have HER2+ tumors (HR+/HER2+: OR 1.29, 95 % CI 1.17-1.42; HR-/HER2+: OR 1.40, 95 %CI 1.25-1.57, vs. HR+/HER2-). Median survival improved over time, but varied substantially across race/ethnicity (Asians: 34 months; African Americans: 6 months), neighborhood socioeconomic status (SES) (highest: 34 months, lowest: 20 months), and molecular subtype (HR+/HER2+: 45 months; triple negative: 12 months). In a multivariable model, triple negative (RH 2.85, 95 % CI 2.50-3.24) and HR-/HER2+ (RH 1.60, 95 % CI 1.37-1.87) had worse, while HR+/HER2+ had similar, risk of all-cause death compared to HR+/HER2- breast cancer.
  
  
  
  De novo metastatic breast cancer was more likely to be HER2+. Among metastatic tumors, those that were HER2+ had better survival than other subtypes.
authors: Cancer Prevention Institute of California, Fremont, CA, USA. li.tao@cpic.org.
authors: Li
authors: L
authors: Tao
authors: Genentech, Inc., San Francisco, CA, USA.
authors: Laura
authors: L
authors: Chu
authors: Genentech, Inc., San Francisco, CA, USA.
authors: Lisa I
authors: LI
authors: Wang
authors: Cancer Prevention Institute of California, Fremont, CA, USA.
authors: Lisa
authors: L
authors: Moy
authors: Genentech, Inc., San Francisco, CA, USA.
authors: Melissa
authors: M
authors: Brammer
authors: Genentech, Inc., San Francisco, CA, USA.
authors: Chunyan
authors: C
authors: Song
authors: Genentech, Inc., San Francisco, CA, USA.
authors: Marjorie
authors: M
authors: Green
authors: Departments of Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Departments of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA.
authors: Allison W
authors: AW
authors: Kurian
authors: Cancer Prevention Institute of California, Fremont, CA, USA.|Departments of Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Departments of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA.
authors: Scarlett L
authors: SL
authors: Gomez
authors: Cancer Prevention Institute of California, Fremont, CA, USA.|Departments of Medicine, Stanford University School of Medicine, Stanford, CA, USA.|Departments of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA.
authors: Christina A
authors: CA
authors: Clarke
mesh_terms: D001741:Black or African American; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D002140:California / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012923:Social Class; D015996:Survival Rate
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: De novo metastatic breast cancer; Subtype