title: Effects of hormone receptor status on the durable response of trastuzumab-based therapy in metastatic breast cancer.
abstract: OBJECTIVE
  Trastuzumab-based treatment is the standard care for patients with HER2+ metastatic breast cancer (MBC). About 10% of HER2+ MBC showed a long-term durable response (progression-free survival, PFS > 3 years) to trastuzumab-based therapy. The aim of this study is to identify clinico-pathologic factors for a durable response to trastuzumab-based therapy in HER2-positive MBC.
  
  
  METHODS
  In the Yonsei Breast Cancer MBC Database, we identified 1218 MBC patients who were diagnosed from 2006 to 2015. Among them, 294 had HER2+ disease, and 153 received trastuzumab plus taxane chemotherapy as first-line treatment. Clinico-pathologic factors, such as hormone receptor (HR) status and metastatic sites, were reviewed. To evaluate a durable response, landmark analysis was performed.
  
  
  RESULTS
  The median follow-up time was 28 months (95% CI 4.4-83.0 months). Of 153 HER2+ patients, there were 73 HR- patients (47.7%), and bone was the most common metastatic site. The median PFS and overall survival (OS) were 12 and 39 months, respectively. HR- patients showed a tendency toward longer PFS (median, 13 vs. 11 months, P = 0.160) compared with HR+ patients. Patients with non-visceral metastases had longer median PFS and OS than those with visceral disease (median PFS, 15 vs. 11 months, P = 0.012; median OS, 75 vs. 34 months, P = 0.03). Landmark analysis at 9 months suggested that the PFS of HR- patients was significantly longer than that of HR+ patients (median, 19 vs. 9 months, P = 0.008).
  
  
  CONCLUSIONS
  Among patients with HER2+ MBC, HR status is a possible predictive biomarker of a durable response to trastuzumab-based therapy.
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea.
authors.forename: Hyung Soon
authors.initials: HS
authors.lastname: Park
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea.
authors.forename: Joohyuk
authors.initials: J
authors.lastname: Sohn
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seung Il
authors.initials: SI
authors.lastname: Kim
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seho
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Park
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea.
authors.forename: Seul Ghi
authors.initials: SG
authors.lastname: Gho
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea.
authors.forename: Hyun Cheol
authors.initials: HC
authors.lastname: Chung
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea.|Department of Biomedical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Soonmyung
authors.initials: S
authors.lastname: Paik
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, 120-752, Seoul, Korea. gmkim77@yuhs.ac.
authors.forename: Gun Min
authors.identifier: http://orcid.org/0000-0001-9167-8682
authors.initials: GM
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000401:mortality / Q000556:secondary; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D000077143:Docetaxel; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D017239:Paclitaxel / Q000008:administration & dosage; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012189:Retrospective Studies; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D000077143:Docetaxel; D017239:Paclitaxel; D018719:Erb-b2 Receptor Tyrosine Kinases; D043823:Taxoids; D000068878:Trastuzumab; C508053:ERBB2 protein, human
keywords: Durable response; Hormone receptor status; Landmark analysis; Trastuzumab