title: Outcomes of trastuzumab therapy in HER2-positive early breast cancer patients.
abstract: BACKGROUND
  Previous large trials with trastuzumab (TZM) showed improved outcome in patients with HER2-positive early-stage breast cancer. However, the efficacy and safety of TZM in Japanese patients have not been fully evaluated. We have therefore conducted an observational study in Japan.
  
  
  METHODS
  This was a retrospective and a prospective observational study in which data on women with histologically confirmed HER2-positive invasive breast cancer who received TZM for stage I-IIIC disease were collected from 56 institutions that participated in the Japan Breast Cancer Research Group and the efficacy of each treatment regimen analyzed.
  
  
  RESULTS
  A total of 2,024 patients treated between July 2009 and June 2011 were initially enrolled in this study; in August 2013, the patient cohort comprised 2,009 patients. Of these, 142 (7.5 %) were aged ≥70 years, 1,097 (58.1 %) had clinically node-negative (cN0) breast cancer, and 883 (47.4 %) were estrogen receptor-positive. Treatment options were neoadjuvant therapy (662 patients) and adjuvant therapy with TZM (1,228 patients). Three-year overall survival (OS) rates in the entire cohort and in the neoadjuvant and adjuvant cohorts, respectively, were 98.9 [95 % confidence interval (CI) 98.2-99.3], 98.3 (95 % CI 96.8-99.1 %), and 99.2 % (95 % CI 98.4-99.6), respectively. Three-year disease-free survival (DFS) rates in the entire cohort and in the neoadjuvant and adjuvant cohorts, respectively were 94.2 (95 % CI 93.0-95.2), 94.8 (95 % CI 93.0-95.9), and 93.1 (95 % CI 90.7-94.9 %), respectively. Multivariate analysis showed that age and nodal status negatively correlated with DFS. Age was the only factor which correlated with OS rate. Adverse events (AEs) associated with TZM and grade 3/4 AEs were reported in 356 (18.8 %) and 14 (0.6 %) patients, respectively. Grade 3/4 cardiac toxicities were reported in 11 patients.
  
  
  CONCLUSIONS
  Based on data from our patient cohort of Japanese women with HER2-positive early-stage breast cancer, the efficacy and safety of systemic therapy with TZM are comparable to data from previously conducted large trials. Progress in anti-HER2 therapy for patients aged ≥70 years who have a poorer prognosis is needed.
authors: Department of Breast Surgery, Tenri Hospital, 200 Mishima-cho, Tenri, Nara, 632-8552, Japan, yamashiro.bcs@gmail.com.
authors: Hiroyasu
authors: H
authors: Yamshiro
authors: Hiroji
authors: H
authors: Iwata
authors: Norikazu
authors: N
authors: Masuda
authors: Naohito
authors: N
authors: Yamamoto
authors: Reiki
authors: R
authors: Nishimura
authors: Shoichiro
authors: S
authors: Ohtani
authors: Nobuaki
authors: N
authors: Sato
authors: Nobuki
authors: N
authors: Sato
authors: Masato
authors: M
authors: Takahashi
authors: Takako
authors: T
authors: Kamio
authors: Kosuke
authors: K
authors: Yamazaki
authors: Tsuyoshi
authors: T
authors: Saito
authors: Makoto
authors: M
authors: Kato
authors: Tecchuu
authors: T
authors: Lee
authors: Shinji
authors: S
authors: Ohno
authors: Katsumasa
authors: K
authors: Kuroi
authors: Toshimi
authors: T
authors: Takano
authors: Masahiro
authors: M
authors: Takada
authors: Shinji
authors: S
authors: Yasuno
authors: Satoshi
authors: S
authors: Morita
authors: Masakazu
authors: M
authors: Toi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D016019:Survival Analysis; D000068878:Trastuzumab / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C508053:ERBB2 protein, human