Breast density change as a predictive surrogate for response to adjuvant endocrine therapy in hormone receptor positive breast cancer

• Published in: Breast cancer research : BCR Vol. 14; no. 4; p. R102
• Main Authors: Kim, Jisun, Han, Wonshik, Moon, Hyeong-Gon, Ahn, Soo, Shin, Hee-Chul, You, Jee-Man, Han, Sae-Won, Im, Seock-Ah, Kim, Tae-You, Koo, Hye, Chang, Jung, Cho, Nariya, Moon, Woo, Noh, Dong-Young
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 06.07.2012; BioMed Central
• Subjects: Adjuvant treatment; Adult; Aged; Analysis; Antineoplastic Agents, Hormonal - therapeutic use; Biological markers; Biomarkers; Breast; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - metabolism; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Cancer; Care and treatment; Chemotherapy, Adjuvant; Combined Modality Therapy; Densitometry; Diseases; Estrogen; Female; Follow-Up Studies; Hormones; Humans; Mammography; Measurement; Middle Aged; Neoplasm Metastasis; Neoplasm Recurrence, Local; Prognosis; Receptors, Estrogen - metabolism; Receptors, Progesterone - metabolism; Relapse; Risk Factors; Tamoxifen; Treatment Outcome; Tumor Burden; Young Adult
• ISSN: 1465-542X; 1465-5411; 1465-542X
• DOI: 10.1186/bcr3221

Anti-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. We 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. At 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. MD 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.