Obesity and Risk of Recurrence or Death After Adjuvant Endocrine Therapy With Letrozole or Tamoxifen in the Breast International Group 1-98 Trial
Ewertz, Marianne × Gray, Kathryn P Regan, Meredith M Ejlertsen, Bent Price, Karen N Thürlimann, Beat Bonnefoi, Hervé Forbes, John F Paridaens, Robert Rabaglio, Manuela Gelber, Richard D Colleoni, Marco Láng, István Smith, Ian E Coates, Alan S Goldhirsch, Aron Mouridsen, Henning T #
Grune & Stratton
Journal of Clinical Oncology vol:30 issue:32 pages:3967-3975
PURPOSETo 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 METHODSThis 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.ResultsSeventeen percent of patients have died. Obese patients (BMI ≥ 30 kg/m(2)) had slightly poorer OS (hazard ratio [HR] = 1.19; 95% CI, 0.99 to 1.44) than patients with normal BMI (< 25 kg/m(2)), whereas no trend in OS was observed in overweight (BMI 25 to < 30 kg/m(2)) 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. CONCLUSIONThere was no evidence that the benefit of letrozole over tamoxifen differed according to patients' BMI.