title: High recurrence risk and use of adjuvant trastuzumab in patients with small, HER2-positive, node-negative breast cancers.
abstract: BACKGROUND
  Five randomized trials of adjuvant trastuzumab have reported significant improvements in recurrence-free survival (RFS) and overall survival. However, patients with node-negative tumors 1 cm or smaller were excluded from these trials. We assessed the recurrence risk and benefit of adjuvant therapy in such patients with small tumors.
  
  
  METHODS
  We identified patients with node-negative breast tumors 1 cm or smaller between April 2003 and December 2007. Patients were categorized according to HER2 status and pathological tumor size (pT <5 mm vs. 5-10 mm), hormone receptor (HR) status and adjuvant chemotherapy. The primary endpoint was RFS.
  
  
  RESULTS
  Of 267 patients included in the analysis, 42 had HER2-positive tumors. The median follow-up was 4.3 years. RFS was worse in patients with HER2-positive tumors than HER2-negative tumors (90.5 vs. 97.7% at 5 years; P = 0.031). In the group with HER2-positive tumors, there were no recurrences in patients with pT<5 mm, but 4 recurrences in those with pT 5-10 mm. RFS was worse in patients with pT 5-10 mm than pT <5 mm (79.0 vs. 100%, P = 0.025). Furthermore 3 recurrences occurred in patients without adjuvant trastuzumab, and 1 recurrence occurred as soon as adjuvant trastuzumab was finished. Our results appear to establish the efficacy of adjuvant trastuzumab therapy. HR status and use of adjuvant chemotherapy were not significantly associated with RFS.
  
  
  CONCLUSIONS
  Patients with HER2-positive, node-negative breast tumors 1 cm or smaller (especially 0.5-1.0 cm) have a significant recurrence risk and the decision to employ adjuvant trastuzumab therapy should be discussed with patients based on our results and those of other studies.
authors.affiliation: Department of Breast Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, 464-8681, Japan. ahorio@aichi-cc.jp
authors.forename: Akiyo
authors.initials: A
authors.lastname: Horio
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujita
authors.forename: Hironori
authors.initials: H
authors.lastname: Hayashi
authors.forename: Masaya
authors.initials: M
authors.lastname: Hattori
authors.forename: Naoto
authors.initials: N
authors.lastname: Kondou
authors.forename: Mai
authors.initials: M
authors.lastname: Yamada
authors.forename: Eri
authors.initials: E
authors.lastname: Adachi
authors.forename: Aya
authors.initials: A
authors.lastname: Ushio
authors.forename: Naomi
authors.initials: N
authors.lastname: Gondou
authors.forename: Aiko
authors.initials: A
authors.lastname: Sueta
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
authors.forename: Hiroji
authors.initials: H
authors.lastname: Iwata
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007564:Japan; D008198:Lymph Nodes / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D012008:Recurrence; D012189:Retrospective Studies; D012306:Risk; D000068878:Trastuzumab; D047368:Tumor Burden
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human