title: Impact of low estrogen/progesterone receptor expression on survival outcomes in breast cancers previously classified as triple negative breast cancers.
abstract: OBJECTIVE
  To evaluate the impact of low estrogen/progesterone receptor (ER/PR) expression and effect of endocrine therapy on survival outcomes in human epidermal growth factor receptor 2 (HER2)-negative tumors with ER/PR <10%, previously labeled as triple negative.
  
  
  METHODS
  In a retrospective review, 1257 patients were categorized according their ER/PR percentages into 3 groups, ER/PR <1% (group A), ER/PR 1% to 5% (group B), and ER/PR 6% to 10% (group C). Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models was used to adjust for patient and tumor characteristics.
  
  
  RESULTS
  Groups A, B, and C had 897 (71.4%), 241 (19.2%), and 119 (9.4%) patients, respectively. After a median follow-up of 40 months there was no significant difference in 3-year recurrence-free survival (RFS): 64%, 67%, and 77% (P = .34) or overall survival (OS): 79%, 81%, and 88% (P = .33) for groups A, B, and C, respectively. ER/PR expression was not an independent predictor for RFS (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.86-1.39; P = .46 for group B, and HR, 0.96; 95% CI, 0.66-1.38; P = .81 for group C, compared with group A), or OS (HR, 1.11; 95% CI, 0.84-1.46; P = .46 for group B, and HR, 0.94; 95% CI, 0.63-1.42; P = .78 for group C, compared with group A). Endocrine therapy had no impact on survival outcomes (RFS: P = .10; OS: P = .45) among groups.
  
  
  CONCLUSIONS
  In this cohort, a low ER/PR level (1%-5%) does not appear to have any significant impact on survival outcomes. There was a tendency for survival advantages in the ER/PR 6% to 10% is seen. Benefit of endocrine therapy in these patients is unclear.
authors.affiliation: Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Kanwal P S
authors.initials: KP
authors.lastname: Raghav
authors.forename: Leonel F
authors.initials: LF
authors.lastname: Hernandez-Aya
authors.forename: Xiudong
authors.initials: X
authors.lastname: Lei
authors.forename: Marianan
authors.initials: M
authors.lastname: Chavez-Macgregor
authors.forename: Funda
authors.initials: F
authors.lastname: Meric-Bernstam
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Buchholz
authors.forename: Aysegul
authors.initials: A
authors.lastname: Sahin
authors.forename: Kim-Anh
authors.initials: KA
authors.lastname: Do
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Hortobagyi
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gonzalez-Angulo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry* / Q000401:mortality*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D012189:Retrospective Studies
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human