Abstract P3-13-02: Ethnicity Difference of Benign Breast Diseases in Breast Cancer and Non-Cancer Patients

Abstract

Abstract Background: Breast cancer (BC) is a heterogeneous disease. Ethnicity differences in BC for Caucasian (CA) and African American (AA) women have been reported, but there is no report on ethnicity differences in benign breast diseases (BBDs) though it is known that BBDs may be precursors or risk factors of BCs. In the Clinical Breast Care Project (CBCP), a comprehensive characterization of BBDs performed on breast biopsies makes it possible to conduct a study on the ethnicity difference of BBDs between CA and AA, in the Cancer and Non-Cancer groups respectively. Method: CA and AA patients undergoing a biopsy were selected from CBCP, totaling 1,963. A Pathology Checklist is available, reporting 131 pathologic conditions including 83 BBDs. In addition, a Core Questionnaire covering information such as demographics, medical history, risk factors, life style, etc. is completed. The Cancer group is composed of 731 CAs and 170 AAs (including in situ, invasive, and malignant NOS), and the Non-Cancer group is composed of 748 CAs and 314 AAs. BBDs with a frequency of <1% in each group were removed from the study leaving a total of 26 BBDs analyzed for the Cancer and 25 BBDs for the Non-Cancer groups. Pearson's Chi-square test was used to analyze statistical significance. Results: The Cancer group showed 6 BBDs significantly associated with the ethnicity; 2 were more frequent in CA, i.e., fat necrosis (5.5% CA vs. 0.6% AA, p =0.011), and mild intraductal hyperplasia (6.8% CA vs. 2.4% AA, p= 0.041). The other 4 BBDs were more frequently observed in AA, which were cysts (47.2% CA vs 56.5% AA, p=0.036), multiple papillomas (8.3% CA vs 15.9% AA, p=0.005), moderate intraductal hyperplasia (18.1% CA vs 28.2% AA, p=0.004), and fibroadenomatoid nodule (5.3% CA 11.8% AA, p= 0.004). These BBDs were not significantly different in the Non-Cancer group between the two ethnicities. Six BBDs were significantly associated with the ethnicity in the Non-Cancer group. Four of them were more frequent in CA, including duct ectasia (9.5% CA vs. 3.2% AA, p=0.001), microcalcifications (35.3% CA vs. 27.4% AA, p=0.015), fibocystic changes (61.0% CA vs. 44.6% AA, p= 1.30E-06), and sclerosing adenosis (21.7% CA vs. 13.4% AA, p=0.002). The other 2 BBDs were more frequent in AA, i.e., sclerosing papilloma (0.7% CA vs 2.6% AA, p=0.025), and fibroadenoma (20.9% CA vs 29.9% AA, p=0.002). These BBDs were not significantly different in the Cancer group between the two ethnicities, for example microcalcifications were 50.1% in CA and 55.9% in AA. Discussion: Multiple papillomas and moderate intraductal hyperplasia are moderate risk factors for BC, and in the Cancer group they were more frequently detected in AA than in CA. Microcalcification as a BC risk factor did not show ethnicity difference in the Cancer group, but was detected more frequently in CA in the Non-Cancer group. It is interesting that not a single BBD was found to be significantly associated with the ethnicity (AA and CA) across the Cancer and the Non-Cancer groups. Thus, the ethnicity difference of BBDs in AA and CA reported here not only suggests possible ethnicity-specific BC risk factors but also generates new hypotheses for future studies. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-13-02.