title: Breast cancer index identifies early-stage estrogen receptor-positive breast cancer patients at risk for early- and late-distant recurrence.
abstract: OBJECTIVE
  Residual risk of relapse remains a substantial concern for patients with hormone receptor-positive breast cancer, with approximately half of all disease recurrences occurring after five years of adjuvant antiestrogen therapy.
  
  
  METHODS
  The objective of this study was to examine the prognostic performance of an optimized model of Breast Cancer Index (BCI), an algorithmic gene expression-based signature, for prediction of early (0-5 years) and late (>5 years) risk of distant recurrence in patients with estrogen receptor-positive (ER(+)), lymph node-negative (LN(-)) tumors. The BCI model was validated by retrospective analyses of tumor samples from tamoxifen-treated patients from a randomized prospective trial (Stockholm TAM, n = 317) and a multi-institutional cohort (n = 358).
  
  
  RESULTS
  Within the Stockholm TAM cohort, BCI risk groups stratified the majority (∼65%) of patients as low risk with less than 3% distant recurrence rate for 0 to 5 years and 5 to 10 years. In the multi-institutional cohort, which had larger tumors, 55% of patients were classified as BCI low risk with less than 5% distant recurrence rate for 0 to 5 years and 5 to 10 years. For both cohorts, continuous BCI was the most significant prognostic factor beyond standard clinicopathologic factors for 0 to 5 years and more than five years.
  
  
  CONCLUSIONS
  The prognostic sustainability of BCI to assess early- and late-distant recurrence risk at diagnosis has clinical use for decisions of chemotherapy at diagnosis and for decisions for extended adjuvant endocrine therapy beyond five years.
authors.affiliation: bioTheranostics, Inc., San Diego, California, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Schnabel
authors.forename: Brock E
authors.initials: BE
authors.lastname: Schroeder
authors.forename: Piiha-Lotta
authors.initials: PL
authors.lastname: Jerevall
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Jankowitz
authors.forename: Tommy
authors.initials: T
authors.lastname: Fornander
authors.forename: Olle
authors.initials: O
authors.lastname: Stål
authors.forename: Adam M
authors.initials: AM
authors.lastname: Brufsky
authors.forename: Dennis
authors.initials: D
authors.lastname: Sgroi
authors.forename: Mark G
authors.initials: MG
authors.lastname: Erlander
mesh_terms: D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D011960:Receptors, Estrogen / Q000235:genetics; D012189:Retrospective Studies; D015996:Survival Rate; D013629:Tamoxifen / Q000008:administration & dosage*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D013629:Tamoxifen