title: Prognostic factors for stage IV hormone receptor-positive primary metastatic breast cancer.
abstract: BACKGROUND
  The purpose of this work was identify potential prognostic factors for survival in patients with primary metastatic hormone receptor-positive breast cancer undergoing endocrine therapy (ET) as first-line treatment.
  
  
  METHODS
  We investigated the clinical and pathological characteristics of 69 newly diagnosed stage IV hormone receptor-positive breast cancer patients undergoing ET between 1999 and 2009, and correlated these factors with disease progression and overall survival.
  
  
  RESULTS
  Multivariate regression analysis revealed that progesterone receptor (PgR) positivity (hazard ratio (HR) 0.248; p = 0.001) and clinical benefits of first-line ET (HR 0.386; p = 0.008) were significant prognostic factors for survival. When first-line ET was not effective, patients for whom second-line ET was effective survived significantly longer than those for whom second-line ET was not effective (median survival time, 45.3 vs. 25.8 months; p = 0.0411).
  
  
  CONCLUSIONS
  PgR positivity and clinical benefits of first-line ET were independent prognostic factors for patients with hormone receptor-positive stage IV breast cancer. Moreover, the benefits of second-line ET in patients with a tumor resistant to first-line ET suggests the existence of drug-specific resistance to ET.
authors.affiliation: Breast and Medical Oncology Division , National Cancer Center Hospital, 5-1-1 Tsukiji, Chuou-ku, Tokyo, 104-0045, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kawano
authors.forename: Chikako
authors.initials: C
authors.lastname: Shimizu
authors.forename: Kenji
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kinoshita
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujii
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fujiwara
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000401:mortality; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000401:mortality; D018275:Carcinoma, Lobular / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism / Q000401:mortality; D019008:Drug Resistance, Neoplasm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
chemical_list: D018931:Antineoplastic Agents, Hormonal; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone