Obesity, Tamoxifen Use, and Outcomes in Women With Estrogen Receptor-Positive Early-Stage Breast Cancer

Open Access
Publisher Website
Google Scholar
Abstract
Background: Obesity is associated with both increased breast cancer risk and poorer prognosis after disease onset. However, little is known about the effect of obesity on treatment efficacy. We evaluated the association of obesity with outcomes and with tamoxifen efficacy in women with early-stage, hormone-responsive breast cancer participating in a multicenter cancer cooperative group clinical trial. Methods: The cohort consisted of 3385 women enrolled in National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-14, a randomized, placebo-controlled trial evaluating tamoxifen for lymph node–negative, estrogen receptor (ER)–positive breast cancer. Hazards of breast cancer recurrence, contralateral breast tumors, other new primary cancers, and several mortality endpoints were evaluated in relation to body mass index (BMI), using statistical modeling to adjust for other prognostic factors. Median follow-up time was 166 months. All statistical tests were two-sided. Results: The hazard of breast cancer recurrence was the same among obese (BMI ⩾30.0 kg/m2) women as compared with underweight and normal-weight women (BMI Conclusions: For women with lymph node–negative, ER-positive breast cancer, obesity was not associated with a material increase in recurrence risk or a change in tamoxifen efficacy. However, because obesity was associated with increased risks of contralateral breast cancer, of other primary cancers, and of overall mortality, it may influence long-term outcomes for breast cancer survivors.

This publication has 76 references indexed in Scilit: