Efficacy of tamoxifen ± aminoglutethimide in normal weight and overweight postmenopausal patients with hormone receptor-positive breast cancer: an analysis of 1509 patients of the ABCSG-06 trial

Br J Cancer. 2013 Apr 16;108(7):1408-14. doi: 10.1038/bjc.2013.114. Epub 2013 Mar 19.


Background: There exists evidence that body mass index (BMI) impacts on the efficacy of aromatase inhibitors in patients with breast cancer. The relationship between BMI and the efficacy of tamoxifen is conflicting. We investigated the impact of BMI on the efficacy of single tamoxifen and tamoxifen plus an aromatase inhibitor in the well-defined prospective study population of the ABCSG-06 trial.

Methods: ABCSG-06 investigated the efficacy of tamoxifen vs tamoxifen plus aminoglutethimide in postmenopausal women with hormone receptor-positive breast cancer. Taking BMI at baseline, patients were classified as normal weight (BMI=18.5-24.9 kg m(-)(2)), overweight (BMI=25-29.9 kg m(-)(2)), and obese (30 kg m(-)(2)) according to WHO criteria.

Results: Overweight+obese patients had an increased risk for distant recurrences (hazard ratio (HR): 1.51; Cox P=0·018) and a worse overall survival (OS; HR: 1·49; Cox P=0·052) compared with normal weight patients. Analysing patients treated with single tamoxifen only, no difference between overweight+obese patients and normal weight patients regarding distant recurrence-free survival (HR: 1.35; Cox P=0·24) and OS (HR: 0.99; Cox P=0·97) could be observed. In contrast, in the group of patients treated with the combination of tamoxifen plus aminoglutethimide, overweight+obese patients had an increased risk for distant recurrences (1.67; Cox P=0·03) and a worse OS (1.47; Cox P=0·11) compared with normal weight patients.

Conclusion: BMI impacts on the efficacy of aromatase inhibitor-based treatment but not single tamoxifen.

Trial registration: ClinicalTrials.gov NCT00309491.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aminoglutethimide / administration & dosage
  • Aminoglutethimide / adverse effects
  • Antineoplastic Agents, Hormonal / administration & dosage
  • Antineoplastic Agents, Hormonal / adverse effects
  • Antineoplastic Agents, Hormonal / therapeutic use
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Aromatase Inhibitors / administration & dosage
  • Aromatase Inhibitors / adverse effects
  • Body Mass Index
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / physiopathology
  • Female
  • Humans
  • Middle Aged
  • Overweight / physiopathology*
  • Postmenopause
  • Prospective Studies
  • Receptors, Cell Surface / biosynthesis
  • Tamoxifen / administration & dosage
  • Tamoxifen / adverse effects
  • Tamoxifen / therapeutic use*
  • Treatment Outcome


  • Antineoplastic Agents, Hormonal
  • Aromatase Inhibitors
  • Receptors, Cell Surface
  • Tamoxifen
  • Aminoglutethimide

Associated data

  • ClinicalTrials.gov/NCT00309491