title: Impact of the 21-gene recurrence score assay compared with standard clinicopathologic guidelines in adjuvant therapy selection for node-negative, estrogen receptor-positive breast cancer.
abstract: BACKGROUND
  The development of multigene assays has proved useful in the clinical management of early-stage breast cancer. The 21-gene recurrence score (RS) assay has been shown to quantify risk of distant recurrence and predict chemotherapy benefit in node-negative and node-positive, estrogen-receptor (ER)-positive breast cancer patients. Small, single-institution series have shown that, compared with standard clinicopathologic criteria, use of RS significantly affects adjuvant chemotherapy recommendations.
  
  
  METHODS
  We performed a retrospective review of RS use and its effect on chemotherapy recommendations in node-negative, ER-positive breast cancer patients at a tertiary care teaching hospital. Patient and tumor characteristics and adjuvant treatment information were obtained on 183 patients with RS results between January 2004 and October 2009. Risk categories were assigned based on the RS and on standard clinicopathologic criteria according to guidelines from NCCN, St. Gallen, and Adjuvant!.
  
  
  RESULTS
  A total of 14 patients were excluded for negative ER status (n=2), insufficient data (n=4), inclusion in TAILORx trial (n=7), and recurrent breast cancer (n=1), leaving 169 patients in the cohort. RS use increased 3-fold over the study period (from 18% in 2004 to 50% in 2009). Tumor grade, ER status, and PR status were significantly correlated with RS category. Overall concordance between RS and NCCN, St. Gallen, and Adjuvant! was 10, 48, and 50%, respectively. Depending on the guideline used for comparison, adjuvant therapy recommendations changed with the addition of the RS in 27-74% of cases.
  
  
  CONCLUSIONS
  RS use is increasing, and the assay significantly reduced adjuvant chemotherapy utilization in node-negative, ER -positive breast cancer patients.
authors.affiliation: Akron General Medical Center, Akron, OH, USA. jpartin@agmc.org
authors.forename: Jessica F
authors.initials: JF
authors.lastname: Partin
authors.forename: Eleftherios P
authors.initials: EP
authors.lastname: Mamounas
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D017024:Chemotherapy, Adjuvant; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D009367:Neoplasm Staging; D017410:Practice Guidelines as Topic; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone