title: Long-term benefits of 5 years of tamoxifen: 10-year follow-up of a large randomized trial in women at least 50 years of age with early breast cancer.
abstract: OBJECTIVE
  The Cancer Research UK "Over 50s" trial compared 5 and 2 years of tamoxifen in women with early breast cancer. Results are reported after median follow-up of 10 years.
  
  
  METHODS
  Between 1987 and 1997, 3,449 patients age 50 to 81 years with operable breast cancer who had been taking 20 mg of tamoxifen for 2 years were randomly assigned to either stop or continue for an additional 3 years, if they were alive and recurrence free. Data on recurrences, new tumors, deaths, and cardiovascular events were obtained (April 2010).
  
  
  RESULTS
  There were 1,103 recurrences, 755 deaths as a result of breast cancer, 621 cardiovascular (CV) events, and 236 deaths as a result of CV events. Fifteen years after starting treatment, for every 100 women who received tamoxifen for 5 years, 5.8 fewer experienced recurrence, compared with those who received tamoxifen for 2 years. The risk of contralateral breast cancer was significantly reduced (hazard ratio, 0.70; 95% CI, 0.48 to 1.00). Among women age 50 to 59 years, there was a 35% reduction in CV events (P = .005) and 59% reduction in death as a result of a CV event (P = .02); in older women, the effect was much smaller and not statistically significant.
  
  
  CONCLUSIONS
  Taking tamoxifen for the recommended 5 years reduces the risk of recurrence or contralateral breast cancer 15 years after starting treatment. It also lowers the risk of CV disease and death as a result of a CV event, particularly among those age 50 to 59 years. Women should therefore be encouraged to complete the full course. Although aromatase inhibitors improve disease-free survival, tamoxifen remains a cheap and highly effective alternative, particularly in developing countries.
authors.affiliation: Cancer Research UK and University College London Cancer Trials Centre, 90 Tottenham Court Rd, London W1T 4TJ United Kingdom. ah@ctc.ucl.ac.uk
authors.forename: Allan
authors.initials: A
authors.lastname: Hackshaw
authors.forename: Michael
authors.initials: M
authors.lastname: Roughton
authors.forename: Sharon
authors.initials: S
authors.lastname: Forsyth
authors.forename: Kathryn
authors.initials: K
authors.lastname: Monson
authors.forename: Krystyna
authors.initials: K
authors.lastname: Reczko
authors.forename: Richard
authors.initials: R
authors.lastname: Sainsbury
authors.forename: Michael
authors.initials: M
authors.lastname: Baum
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D047072:Aromatase Inhibitors / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology; D012008:Recurrence; D013629:Tamoxifen / Q000008:administration & dosage*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D013629:Tamoxifen