title: Risk of Recurrence or Contralateral Breast Cancer More than 5 Years After Diagnosis of Hormone Receptor-Positive Early-Stage Breast Cancer.
abstract: Three large studies have shown a survival benefit from 10 years of adjuvant hormone therapy (AHT). We evaluated the risk of an event 5 years after the initial breast cancer (BC) diagnosis and identified the prognostic factors to assist clinicians considering extended AHT.
  
  
  
  Patients newly referred to the BC Cancer Agency with stage I to III estrogen receptor-positive BC diagnosed from 1989 to 2004 who had undergone AHT were identified by the BC Cancer Agency's Breast Cancer Outcomes Unit. Cases with recurrence, death, or contralateral BC occurring within the first 5 years were excluded. The 10-year event-free survival (EFS) and 95% confidence intervals (CIs) were calculated using the Kaplan-Meier method. This provided estimates of recurrence risk after the fifth year following the diagnosis. The histopathologic and age variables were examined for prognostic value by univariate analysis.
  
  
  
  Within our cohort, 6615 women were postmenopausal and 1886 were premenopausal at the BC diagnosis. The median follow-up period was 11 years. The 10-year EFS for women aged < 50 years with stage I, II, and III disease was 94.8% (95% CI, 92.8%-96.3%), 88.3% (95% CI, 86.0%-90.2%), and 80.4% (95% CI, 73.6%-85.6%), respectively. Among women aged ≥ 50 years, the corresponding EFS rates were 94.8% (95% CI, 93.8%-95.6%), 86.3% (95% CI, 85.0%-87.5%), and 73.8% (95% CI, 69.1%-77.8%). EFS varied significantly by grade. The 10-year recurrence risk was < 10% with stage I cancer (any grade) and for stage II (node-negative and node-positive), grade I cancer.
  
  
  
  Our data have identified BCs associated with a very low recurrence risk 5 to 10 years after diagnosis, providing women with such cancers confidence about a decision to discontinue AHT after 5 years.
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada.
authors.forename: Sheridan
authors.initials: S
authors.lastname: Wilson
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Speers
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Tyldesley
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Chia
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada.
authors.forename: Hagen
authors.initials: H
authors.lastname: Kennecke
authors.affiliation: BC Cancer Agency, Centre for the Southern Interior, Kelowna, BC, Canada.
authors.forename: Susan
authors.initials: S
authors.lastname: Ellard
authors.affiliation: BC Cancer Agency, Vancouver Cancer Centre, Vancouver, BC, Canada. Electronic address: clohrisch@bccancer.bc.ca.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lohrisch
mesh_terms: D000367:Age Factors; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D017024:Chemotherapy, Adjuvant / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018570:Risk Assessment; D013629:Tamoxifen / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D011960:Receptors, Estrogen; D013629:Tamoxifen
keywords: Adjuvant hormone therapy; Five versus 10 years of therapy; Good prognosis groups; Hormone receptor-positive breast cancer; Late recurrence risk