title: The prevalence of estrogen receptor-negative breast cancer in Ethiopia.
abstract: BACKGROUND
  In contrast with breast cancers (BCs) in other parts of the world, most previous studies reported that the majority of BCs in sub-Saharan Africa are estrogen-receptor (ER) negative. However, a recent study using the US SEER database showed that the proportion of ER-negative BC is comparable between US-born blacks and West-African born blacks but substantially lower in East African-born blacks, with over 74% of patients Ethiopians or Eritreans. In this paper, we provide the first report on the proportion of ER-negative BC in Ethiopia, and the relation to progesterone-receptor (PgR) status.
  
  
  METHODS
  We analysed 352 female patients with ER results available out of 1208 consecutive female BC patients treated at Addis Ababa-University Hospital, Ethiopia, from June 2005 through December 2010. The influences of age, stage, and histology on the probability of ER-negative tumours were assessed by a log-linear regression model.
  
  
  RESULTS
  Of the 352 patients, only 35% were ER-negative. The proportion of ER-negative tumours decreased with advancing age at diagnosis and was not affected by histology or stage. For age, the proportion decreased by 6% for each additional 5 years (stage-adjusted prevalence ratio PR=0.94, 95% CI: 0.89-1.00). About 31% were ER- and PgR-negative, and 69% were ER- and/or PgR-positive.
  
  
  CONCLUSIONS
  Contrary to most previous reports in other parts of sub-Saharan Africa, the majority of patients in Ethiopia are ER-positive rather than ER-negative. These findings are in line with low proportions of ER-negative BCs from East African immigrants within the SEER database, and they have clinical implications for management of BC patients in Ethiopia and other parts of sub-Saharan Africa where ER-status is not ascertained as part of routine management of the disease. Since the majority of patients showed ER-positive BC, Tamoxifen-therapy should be given to all patients even with unknown ER status.
authors.affiliation: Department of Gynecology and Institute of Clinical Epidemiology, Martin-Luther-University, Ernst-Grube Str, 40, 06097 Halle an der Saale, Germany. eva.kantelhardt@uk-halle.de.
authors.forename: Eva Johanna
authors.initials: EJ
authors.lastname: Kantelhardt
authors.forename: Assefa
authors.initials: A
authors.lastname: Mathewos
authors.forename: Abreha
authors.initials: A
authors.lastname: Aynalem
authors.forename: Tigeneh
authors.initials: T
authors.lastname: Wondemagegnehu
authors.forename: Ahmedin
authors.initials: A
authors.lastname: Jemal
authors.forename: Martina
authors.initials: M
authors.lastname: Vetter
authors.forename: Erdme
authors.initials: E
authors.lastname: Knauf
authors.forename: Anne
authors.initials: A
authors.lastname: Reeler
authors.forename: Solomon
authors.initials: S
authors.lastname: Bogale
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomssen
authors.forename: Andreas
authors.initials: A
authors.lastname: Stang
authors.forename: Tufa
authors.initials: T
authors.lastname: Gemechu
authors.forename: Pietro
authors.initials: P
authors.lastname: Trocchi
authors.forename: Bekuretsion
authors.initials: B
authors.lastname: Yonas
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000737:chemistry / Q000453:epidemiology* / Q000378:metabolism*; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D011960:Receptors, Estrogen