Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial

Marianne Ewertz, Kathryn P. Gray, Meredith M. Regan, Bent Ejlertsen, Karen N. Price, Beat Thürlimann, Hervé Bonnefoi, John F. Forbes, Robert J. Paridaens, Manuela Rabaglio, Richard D. Gelber, Marco Colleoni, István Láng, Ian E. Smith, Alan S. Coates, Aron Goldhirsch, Henning T. Mouridsen

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Abstract

Purpose: To examine the association of baseline body mass index (BMI) with the risk of recurrence or death in postmenopausal women with early-stage breast cancer receiving adjuvant tamoxifen or letrozole in the Breast International Group (BIG) 1-98 trial at 8.7 years of median follow-up. Patients and Methods: This report analyzes 4,760 patients with breast cancer randomly assigned to 5 years of monotherapy with letrozole or tamoxifen in the BIG 1-98 trial with available information on BMI at randomization. Multivariable Cox modeling assessed the association of BMI with disease-free survival, overall survival (OS), breast cancer-free interval, and distant recurrence-free interval and tested for treatment-by-BMI interaction. Median follow-up was 8.7 years. Results: Seventeen percent of patients have died. Obese patients (BMI ≥ 30 kg/m2) had slightly poorer OS (hazard ratio [HR] = 1.19; 95% CI, 0.99 to 1.44) than patients with normal BMI (<25 kg/m2), whereas no trend in OS was observed in overweight (BMI 25 to <30 kg/m2) versus normal-weight patients (HR = 1.02; 95% CI, 0.86 to 1.20). Treatment-by-BMI interactions were not statistically significant. The HRs for OS comparing obese versus normal BMI were HR = 1.22 (95% CI, 0.93 to 1.60) and HR = 1.18 (95% CI, 0.91 to 1.52) in the letrozole and tamoxifen groups, respectively. Conclusion: There was no evidence that the benefit of letrozole over tamoxifen differed according to patients' BMI.

Original languageEnglish
Pages (from-to)3967-3975
Number of pages9
JournalJournal of Clinical Oncology
Volume30
Issue number32
DOIs
Publication statusPublished - Nov 10 2012

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ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Ewertz, M., Gray, K. P., Regan, M. M., Ejlertsen, B., Price, K. N., Thürlimann, B., Bonnefoi, H., Forbes, J. F., Paridaens, R. J., Rabaglio, M., Gelber, R. D., Colleoni, M., Láng, I., Smith, I. E., Coates, A. S., Goldhirsch, A., & Mouridsen, H. T. (2012). Obesity and risk of recurrence or death after adjuvant endocrine therapy with letrozole or tamoxifen in the breast international group 1-98 trial. Journal of Clinical Oncology, 30(32), 3967-3975. https://doi.org/10.1200/JCO.2011.40.8666