Estrogen receptor, Progesterone receptor, HER2 status and Ki67 index and responsiveness to adjuvant tamoxifen in postmenopausal high-risk breast cancer patients enrolled in the DBCG 77C trial

Research output: Research - peer-reviewJournal article

DOI

  • Ann S Knoop
    Ann S Knoop
  • Anne-Vibeke Lænkholm
    Anne-Vibeke Lænkholm
  • Maj-Britt Jensen
    Maj-Britt Jensen
  • Kirsten V Nielsen
  • Jørn Andersen
  • Dorte Nielsen
    Dorte Nielsen
  • Bent Ejlertsen
    Bent Ejlertsen
  • Danish Breast Cancer Cooperative Group
  • The Department of Oncology
Background
The DBCG 77C trial compared one year of tamoxifen in postmenopausal, steroid-receptor unknown, high-risk breast cancer patients to no adjuvant systemic therapy. After a potential follow-up of 30 years we report overall efficacy of the study and results according to subtypes subsequently assessed by immunohistochemistry and fluorescent in situ hybridisation (FISH).

Methods
Between 1977 and 1982, 1716 postmenopausal patients with tumours larger than 5 cm or positive axillary nodes were randomly assigned to no systemic therapy or tamoxifen 30 mg daily for one year. Archival tumour tissue from 1515 patients was analysed and the hormone receptor positive (estrogen receptor (ER) and/or progesterone receptor (PR)) cancers were defined as luminal A if Ki67 low and HER2-negative; as luminal B if Ki67 high or HER2-positive; and otherwise as non-luminal-HER2 positive or triple negative.

Findings
In the intent-to-treat (ITT) population one year of tamoxifen improved the disease-free-survival (DFS) (hazard ratio (HR) = 0.87; 95% confidence interval (CI) 0.77–0.98), the Breast Cancer Recurrence Rate (BCRR) (HR = 0.79; 0.69–0.90) and reduced the breast-cancer-specific-mortality (BCM) (HR = 0.83; 0.73–0.93). BCRR were improved significantly by tamoxifen in luminal A (HR = 0.66; 0.53–0.84) and luminal B/HER2– (HR = 0.54; 0.39–0.74) but not in the other subsets, and with similar results for BCM with 30 years follow-up.

Interpretation
One year of treatment with tamoxifen significantly improves BCRR and BCM in postmenopausal patients with ER positive breast cancers. The relative benefit from tamoxifen was not significantly different in luminal A and B subtypes.
Original languageEnglish
JournalEuropean journal of cancer (Oxford, England : 1990)
Volume50
Issue number8
Pages (from-to)1412-21
Number of pages10
ISSN0959-8049
DOIs
StatePublished - May 2014

    Research areas

  • Adult, Aged, Antineoplastic Agents, Hormonal, Breast Neoplasms, Chemotherapy, Adjuvant, Disease-Free Survival, Female, Follow-Up Studies, Humans, Immunohistochemistry, In Situ Hybridization, Fluorescence, Intention to Treat Analysis, Ki-67 Antigen, Middle Aged, Postmenopause, Receptor, ErbB-2, Receptors, Estrogen, Receptors, Progesterone, Risk Factors, Survival Analysis, Tamoxifen, Treatment Outcome

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