title: Effect of adjuvant trastuzumab among patients treated with anti-HER2-based neoadjuvant therapy.
abstract: OBJECTIVE
  To study the impact of adjuvant trastuzumab among patients achieving a pathologic complete response (pCR) after trastuzumab-based neoadjuvant systemic therapy (NST).
  
  
  METHODS
  Patients with primary HER2-positive breast cancer treated with trastuzumab-based NST were categorised according to adjuvant trastuzumab administration and pCR status. Adjuvant trastuzumab became standard of care in 2006, this was the main reason patients in our cohort did not receive adjuvant trastuzumab. Kaplan-Meier was used to estimate survival. A test for interaction between adjuvant trastuzumab and pCR was completed.
  
  
  RESULTS
  Of 589 patients, 203 (34.5%) achieved a pCR. After surgery, 109 (18.5%) patients in the entire cohort did not receive adjuvant trastuzumab. Among patients achieving a pCR, 31.3% received adjuvant trastuzumab compared with 68.8% among those who did not achieve a pCR (P=0.0006). Among patients achieving pCR, adjuvant trastuzumab did not further improve overall survival (OS) or relapse-free survival (RFS) (P=0.35 and P=0.93, respectively). Any benefit of adjuvant trastuzumab in OS and RFS among patients without a pCR did not achieve statistical significance (P=0.3 and P=0.44, respectively).
  
  
  CONCLUSIONS
  In this cohort, patients treated with trastuzumab-based NST who achieved a pCR have excellent outcome regardless of whether they received adjuvant trastuzumab.
authors.affiliation: 1] Department of Breast Medical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA [2] Department of Systems Biology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Gonzalez-Angulo
authors.affiliation: Department of Breast Medical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: N
authors.initials: N
authors.lastname: Parinyanitikul
authors.affiliation: Department of Biostatistics at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: X
authors.initials: X
authors.lastname: Lei
authors.affiliation: Department of Surgical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Mittendorf
authors.affiliation: Department of Pathology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Breast Medical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: V
authors.initials: V
authors.lastname: Valero
authors.affiliation: Department of Surgical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Hunt
authors.affiliation: Department of Breast Medical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: G N
authors.initials: GN
authors.lastname: Hortobagyi
authors.affiliation: 1] Department of Breast Medical Oncology at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA [2] Department of Health Services Research at The University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: M
authors.initials: M
authors.lastname: Chavez-MacGregor
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D003520:Cyclophosphamide / Q000008:administration & dosage; D015251:Epirubicin / Q000008:administration & dosage; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D017239:Paclitaxel / Q000008:administration & dosage; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D012189:Retrospective Studies; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D003520:Cyclophosphamide; D015251:Epirubicin; D005472:Fluorouracil; D017239:Paclitaxel; D047428:Protein Kinase Inhibitors; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human