Prognostic value of Ki67 expression after short-term presurgical endocrine therapy for primary breast cancer

IMPACT Trialists Group, Mitch Dowsett, Ian E Smith, Stephen R Ebbs, J Michael Dixon, Anthony Skene, Roger A'Hern, Janine Salter, Simone Detre, Margaret Hills, Geraldine Walsh

Research output: Contribution to journalArticlepeer-review


Tumor expression of the proliferation antigen Ki67 is widely used to assess the prognosis of cancer patients. A change in the expression of Ki67 after short-term exposure of patients to therapeutic agents is frequently used as a pharmacodynamic marker of efficacy, particularly among breast cancer patients before undergoing surgery. To determine the clinical significance of the level of tumor cell proliferation during endocrine therapy for breast cancer, we measured the expression of Ki67 in tumor biopsy samples taken before and after 2 weeks of presurgical treatment with anastrozole or tamoxifen or the combination of anastrozole plus tamoxifen in 158 patients with hormone receptor-positive primary disease. In a multivariable analysis, we found that higher Ki67 expression after 2 weeks of endocrine therapy was statistically significantly associated with lower recurrence-free survival (P = .004) whereas higher Ki67 expression at baseline was not. Larger baseline tumor size and lower estrogen receptor level after 2 weeks of treatment were also statistically significantly associated with poorer recurrence-free survival (P
Original languageEnglish
Pages (from-to)167-70
Number of pages4
JournalJournal of the National Cancer Institute (JNCI)
Issue number2
Publication statusPublished - 17 Jan 2007


  • Adult
  • Aged
  • Analysis of Variance
  • Antineoplastic Agents, Hormonal
  • Breast Neoplasms
  • Chemotherapy, Adjuvant
  • Disease-Free Survival
  • Female
  • Follow-Up Studies
  • Humans
  • Ki-67 Antigen
  • Middle Aged
  • Multivariate Analysis
  • Neoadjuvant Therapy
  • Neoplasms, Hormone-Dependent
  • Nitriles
  • Predictive Value of Tests
  • Prognosis
  • Proportional Hazards Models
  • Receptors, Estrogen
  • Sample Size
  • Tamoxifen
  • Triazoles
  • Tumor Markers, Biological


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