title: Outcomes in patients with early-stage breast cancer who underwent a 21-gene expression assay.
abstract: BACKGROUND
  Invasive disease-free survival (IDFS) rates are excellent in patients with breast cancer (BC) with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-), axillary lymph node-negative (LN-) tumors with a 21-gene expression assay recurrence score (RS) of 0 to 10. However, to the authors' knowledge, the outcomes among patients with an RS of 11 to 25 who are treated with endocrine therapy alone are unknown.
  
  
  METHODS
  In this retrospective single-institution study, the authors described the characteristics of patients with HR+, HER2-, LN- BC who underwent a 21-gene expression assay. In addition, among those individuals diagnosed between 2005 and 2011, we measured IDFS, recurrence-free survival, distant recurrence-free survival, and overall survival rates, focusing on patients with an RS of 11 to 25 by receipt of chemotherapy. The Kaplan-Meier method was used to estimate survival rates and multivariable Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals (95% CIs).
  
  
  RESULTS
  Among 1424 patients, the RS distribution was 0 to 10 in 297 patients (21%), 11 to 25 in 894 patients (63%), and >25 in 233 patients (16%); of these, 1.7%, 15%, and 73.4% of patients, respectively, received chemotherapy. With a median follow-up of 58 months, those patients with an RS of 11 to 25 had an IDFS rate at 5 years of 92.6% (95% CI, 89.6%-94.7%), which was comparable between those who received chemotherapy and those who did not. The hazard ratios of the effect of chemotherapy were 1.64 for IDFS (95% CI, 0.73-3.71), 1.46 for recurrence-free survival (95% CI, 0.41-5.23), 1.25 for distant recurrence-free survival (95% CI, 0.32-4.92), and 2.19 for overall survival (95% CI, 0.44-11.0).
  
  
  CONCLUSIONS
  The results of the current study demonstrate similar outcomes with or without chemotherapy in patients with HR+, HER2-, LN- BC who have an RS of 11 to 25, but a benefit from chemotherapy in this group cannot be ruled out. Cancer 2017;123:2422-31. © 2017 American Cancer Society.
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Barcenas
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Akshara
authors.initials: A
authors.lastname: Raghavendra
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.|Department of Biostatistics, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Arup K
authors.initials: AK
authors.lastname: Sinha
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Masood Pasha
authors.initials: MP
authors.lastname: Syed
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Limin
authors.initials: L
authors.lastname: Hsu
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Modesto G
authors.initials: MG
authors.lastname: Patangan
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.|Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Mariana
authors.initials: M
authors.lastname: Chavez-MacGregor
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Gabriel H
authors.initials: GH
authors.lastname: Hortobagyi
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Vicente
authors.initials: V
authors.lastname: Valero
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.|Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Sharon H
authors.initials: SH
authors.lastname: Giordano
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Naoto T
authors.initials: NT
authors.lastname: Ueno
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Debu
authors.initials: D
authors.lastname: Tripathy
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D018275:Carcinoma, Lobular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D053208:Kaplan-Meier Estimate; D008408:Mastectomy; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D011878:Radiotherapy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: chemotherapy; early-stage breast cancer; gene expression assays; hormone receptor positive; tumor genomics