Risk of early recurrence among postmenopausal women with estrogen receptor-positive early breast cancer treated with adjuvant tamoxifen

Authors

  • Hagen Kennecke MD, MHA,

    Corresponding author
    1. Division of Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    3. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    • Vancouver Cancer Clinic, 600 West 10th Avenue, Vancouver, BC, V5Z 4E6, Canada
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    • Fax: (604) 877-0585.

  • Heather McArthur MD,

    1. Division of Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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  • Ivo A. Olivotto MD,

    1. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    2. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    3. Division of Radiation Oncology, British Columbia Cancer Agency, Victoria, British Columbia, Canada
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  • Caroline Speers BA, CHIM,

    1. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Population and Preventive Oncology Program, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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  • Chris Bajdik MD,

    1. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Cancer Control Research, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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  • Stephen K. Chia MD,

    1. Division of Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    3. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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  • Susan Ellard MD,

    1. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    2. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    3. Division of Medical Oncology, Cancer Center of Southern Interior, British Columbia Cancer Agency, British Columbia, Canada
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  • Brian Norris MD,

    1. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    2. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    3. Division of Medical Oncology, British Columbia Cancer Agency, Surrey, British Columbia, Canada
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  • Malcolm Hayes MD,

    1. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    2. Department of Pathology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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  • Jeff Barnett BSC (Pharm),

    1. Systemic Therapy Program, British Columbia Cancer Agency, Victoria, British Columbia, Canada
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  • Karen A. Gelmon MD

    1. Division of Medical Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
    2. Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    3. Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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  • Presented in part at the 28th Annual San Antonio Breast Cancer Conference, San Antonio, Texas, December 7–11, 2005.

Abstract

BACKGROUND

Adjuvant aromatase inhibitors (AIs), instead of or after tamoxifen, are effective in decreasing recurrence in postmenopausal women with estrogen receptor (ER)-positive breast cancer. An understanding of which patients are at risk of early recurrence while they are receiving tamoxifen may improve clinical decision making.

METHODS

The patients who were included in this study were women aged ≥50 years with early-stage, ER-positive breast cancer diagnosed between 1986 and 1999 and had been treated with tamoxifen. Characteristics of the patients with early recurrences (within 2.5 years of diagnosis), late recurrences (between 2.5 years and 5 years) and no recurrence within 5 years were compared. Logistic regression analyses were conducted to identify which groups were at risk of early recurrence.

RESULTS

Among 3844 women, 304 women (7.9%) developed disease recurrence within 2.5 years. Higher than average rates of recurrence within 2.5 years were observed in cohorts with lymph node (N)-positive tumors (11.5%), grade 3 histology (14.3%), or low-positive ER levels, ie, 10–49 fmol/mg or 10%–20% staining (14.9%). In multivariate analyses, only pathologically N-positive tumors (1–3 vs 0 positive lymph nodes: odds ratio [OR], 1.6; 4–9 vs 0 positive lymph nodes: OR, 2.23 [P = .03]) and low-positive ER status (OR, 2.04; P = .01) were associated with recurrence within 2.5 years compared with recurrence between 2.5 years and 5 years. Other clinical and pathologic variables were not predictive of early recurrence.

CONCLUSIONS

Subgroups of women with early ER-positive breast cancer may be identified who are at increased risk of recurrence within 2.5 years of diagnosis despite tamoxifen. It remains to be proven whether upfront AI therapy results in an advantage to these women. Cancer 2008. © 2008 American Cancer Society.

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