Association between race and BMI with response to neoadjuvant endocrine therapy in postmenopausal women with large estrogen receptor-positive breast cancers.

Abstract

132 Background: Neoadjuvant endocrine therapy is increasingly used in the treatment of breast cancer. There is a need to define which patients will benefit the most from this form of therapy. Methods: Retrospective review of medical records from University of Miami/Jackson Memorial Hospital from 1998 to 2011. Response to neoadjuvant endocrine therapy was evaluated through comparison of palpable breast mass size at presentation with pathological tumor size in surgical specimens. Response was stratified as “No Response” (NR), indicating no change or increase in size, “Moderate Response” (MR) as up to 50% decrease in size, and “Good Response” (GR) > 50% decrease in size. Data was analyzed by body mass index (BMI), type of endocrine therapy, race and histology. Results: Data from 62 postmenopausal, estrogen receptor-positive women who received neoadjuvant hormonal therapy was analyzed. Median age was 62 (range 50-91). Clinical stage: II 24.2%, IIIA 25.8%, IIIB 35.5%, IIIC 6.5%. Endocrine therapy used was tamoxifen (14.5%) or aromatase inhibitor (AI) (85.5%). Response rate was NR in 22.6%, MR in 43.5% and GR in 33.9%. Fifty two patients had available height and weight information. In patients receiving AI, BMI was significantly higher in the NR group vs. GR group (mean BMI 38.68 vs. 27.56, p=0.041). Mean BMI in MR was 32.18, not statistically different from either group. Analysis of both AI and tamoxifen treated patients yielded similar results (results not included). The rate of GR was higher in the Caucasian vs. African American population (40.4% vs. 14.3%, p=0.017). Inversely, the rate of NR was higher in African Americans (50.0% vs. 14.9%, p=0.017). There was a trend towards more favorable tumor size change in Caucasian vs. African American women (mean 36.19% reduction vs. 11.69% increase in tumor size, p=0.058). The mean tumor size change was more favorable in ductal vs. lobular carcinomas (34.75% decrease vs 8.69% increase, p=0.184). Conclusions: Lower BMI and Caucasian ethnicity were associated with higher frequency of GR (> 50% decrease in tumor size) to neoadjuvant endocrine therapy. No association was found between response and stage, PR status or HER2 expression.