Abstract P3-01-03: Milky Way sign: A potential predictive sign of breast cancer on digital breast tomosynthesis
Authors: Miyake KK , Lipson JA , Allison KH , Xu Y , Liu YI , Downey JR , Ikeda DM 
Published: March 2017

Purpose: “Milky Way sign (MWS)”, which we recently reported1), is a new finding on digital breast tomosynthesis (DBT) showing microcalcifications overlying non-calcified band-like density. Our study purpose was to describe frequencies of and imaging findings associated with MWS, and to examine the predictive value of MWS for breast cancer.

Materials and Methods: We reviewed all stereotactic core biopsies of suspicious calcifications at our institution from 1/1/2015 to 12/31/2015, finding 124 lesions with calcifications, including 20 malignancies (2 IDC, 5 IDC+DCIS, 13 DCIS) and 104 non-malignant lesions (23 high-risk [14 ADH, 6 LCIS/ALH, 1 intraductal papilloma, 2 other atypical], 81 benign), in 116 patients undergoing both 2D mammogram and DBT before biopsies. 2 radiologists reviewed images for the presence of MWS, local breast density within 1 cm surrounding the calcifications, classifying BI-RADS calcification morphology and distribution. We assessed the predictive value of MWS for malignancy using Chi square test and multivariate logistic analysis.

Results: MWS was identified more frequently with DBT (27/124, 22%) than with 2D (13/124, 10%), and more in locally less dense tissue than in locally dense tissue. The calcifications in MWS were fine pleomorphic (13/27, 48%), amorphous (8/27, 30%), fine linear/branching (5/27, 19%), or other (1/27, 4%), with distributions of grouped (20/27, 74%), linear (5/27, 19%) or segmental (2/27, 7%) categories. MWS on DBT was observed in 60% (12/20, including 2 IDC, 2 IDC+DCIS, 8 DCIS) of malignant lesions and 14% (15/104) of benign lesions (table1), and was significantly and positively associated with malignant lesions (p &lt; .001). Multivariate analysis demonstrated the MWS on DBT (p &lt; .001) and fine linear/branching calcifications (p &lt; .001) were independent predictors for malignancy.

Frequencies of MWS on DBT according to histopathology nMWS positiveMWS negativeMalignancy2012 (60)8 (40)-IDC22 (100)0 (0)-IDC+DCIS52 (40)3 (60)-DCIS138 (62)5 (38)Non-malignant lesion10415 (14)89 (86)-ADH143 (21)11 (79)-LCIS/ALH60 (0)6 (100)-Intraductal papilloma10 (0)1 (100)-Other high-risk20 (0)2 (100)-Benign8112 (15)69 (85)Total12427 (22)97 (78)Data are shown as number with percentage in parenthesis.

Conclusions: Although sample size was limited, our results indicate that DBT may contribute in detecting MWS, and that MWS may be a predictive sign for breast cancers, leading to biopsy of suspicious calcifications.

Reference 1) Xu Y, Miyake KK, Liu YI, Downey JR, Lipson J, Allison K, Ikeda DM. “The Milky Way Sign: a new diagnostic findings of ductal carcinoma on digital tomosynthesis.” The Breast Journal. 2016 May; 22 (3):349-51.

Citation Format: Miyake KK, Lipson JA, Allison KH, Xu Y, Liu YI, Downey JR, Ikeda DM. Milky Way sign: A potential predictive sign of breast cancer on digital breast tomosynthesis [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-01-03.