Abstract
IntroductionAnti-estrogen therapy has been shown to reduce mammographic breast density (MD). We hypothesized that a short-term change in breast density may be a surrogate biomarker predicting response to adjuvant endocrine therapy (ET) in breast cancer.MethodsWe analyzed data for 1,065 estrogen receptor (ER)-positive breast cancer patients who underwent surgery between 2003 and 2006 and received at least 2 years of ET, including tamoxifen and aromatase inhibitors. MD was measured using Cumulus software 4.0 and expressed as a percentage. MD reduction (MDR) was defined as the absolute difference in MD of mammograms taken preoperatively and 8-20 months after the start of ET.ResultsAt a median follow-up of 68.8 months, the overall breast cancer recurrence rate was 7.5% (80/1065). Mean MDR was 5.9% (range, -17.2% to 36.9%). Logistic regression analysis showed that age < 50 years, high preoperative MD, and long interval between start of ET to follow-up mammogram were significantly associated with larger MDR (p < 0.05). In a survival analysis, tumor size, lymph node positivity, high Ki-67 (≥ 10%), and low MDR were independent factors significantly associated with recurrence-free survival (p < 0.05). Compared with the group showing the greatest MDR (≥ 10%), the hazard ratios for MDRs of 5-10%, 0-5%, and < 0% were 1.33, 1.92, and 2.26, respectively.ConclusionsMD change during short-term use of adjuvant ET was a significant predictor of long-term recurrence in women with ER-positive breast cancer. Effective treatment strategies are urgently needed in patients with low MDR despite about 1 year of ET.
Highlights
Anti-estrogen therapy has been shown to reduce mammographic breast density (MD)
Factors associated with density change Patients were dichotomized by degree of MD reduction using a cut-off of 5% (MDR ≥ 5% vs. < 5%), and factors in the two groups were compared to identify associations with high Mammographic density reduction (MDR)
Patients with MDR ≥ 5% were significantly younger (46.5 ± 8.0 vs. 51.9 ± 9.8 years, P < 0.001; Additional file 1, Table S1) and were significantly more likely to have been treated with tamoxifen than with an aromatase inhibitor (P < 0.001)
Summary
We hypothesized that a short-term change in breast density may be a surrogate biomarker predicting response to adjuvant endocrine therapy (ET) in breast cancer. High MD is associated with increased risk of breast cancer in both Western and Asian women [1,2]. Studies on the efficacy of tamoxifen for chemoprevention of breast cancer in high-risk women have shown that MD is decreased following tamoxifen treatment [4,5]. No studies to date have addressed the association between MD reduction and the efficacy of adjuvant endocrine treatment in breast cancer patients. Using quantitative imaging analysis software to assess serial changes in MD, we investigated the association between the degree of MD reduction and long-term breast cancer recurrence in ER-positive breast cancer patients who received adjuvant endocrine therapy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
