title: Assessment of the contribution of the IHC4+C score to decision making in clinical practice in early breast cancer.
abstract: BACKGROUND
  The immunohistochemical (IHC) 4+C score is a cost-effective prognostic tool that uses clinicopathologic factors and four standard IHC assays: oestrogen receptor (ER), PR, HER2 and Ki67. We assessed its utility in personalising breast cancer treatment in a clinical practice setting, through comparison with Adjuvant! Online (AoL) and the Nottingham Prognostic Index (NPI).
  
  
  METHODS
  We prospectively gathered clinicopathologic data for postmenopausal patients with hormone receptor-positive, HER2-negative, N0-3 resected early breast cancer treated consecutively at our institution. We retrospectively calculated and compared prognostic scores. The primary endpoint was the proportion of patients reclassified from AoL-defined intermediate-risk by application of the IHC4+C score.
  
  
  RESULTS
  The median age of the 101 patients included in the analysis was 63. In all, 15 of the 26 patients classified as intermediate-risk by AoL were reallocated to a low-risk group by application of the IHC4+C score and no patient was reclassified as high-risk group. Of the 59 patients classified as intermediate-risk group by the NPI, 24 were reallocated to a low-risk group and 13 to a high-risk group.
  
  
  CONCLUSIONS
  IHC4+C reclassifies more than half of the patients stratified as being in intermediate-risk group by the AoL and NPI. The use of IHC4+C may substantially improve decision-making on adjuvant chemotherapy.
authors.affiliation: Department of Medicine, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK.
authors.forename: S
authors.initials: S
authors.lastname: Barton
authors.forename: L
authors.initials: L
authors.lastname: Zabaglo
authors.forename: R
authors.initials: R
authors.lastname: A'Hern
authors.forename: N
authors.initials: N
authors.lastname: Turner
authors.forename: T
authors.initials: T
authors.lastname: Ferguson
authors.forename: S
authors.initials: S
authors.lastname: O'Neill
authors.forename: M
authors.initials: M
authors.lastname: Hills
authors.forename: I
authors.initials: I
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Dowsett
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000188:drug therapy; D017024:Chemotherapy, Adjuvant; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone