Abstract P2-02-05: Combined Ultrasound/MRI for Breast Cancer Screening in Asian Women of Average Cancer Risk

Abstract

Abstract Background and purpose: MRI is not recommended for screening women at average risk because it is associated with substantial numbers of false-positive results and cost. MRI as a screening tool for breast cancer, however, involves a complexity of cancer epidemiology, socio-economic situation, healthcare policy, and awareness and compliance of general population. Breast MRI may be particularly beneficial as a screening tool for Asian women due to their dense breast. In this study we reported the breast MRI screening results in Chinese women in Taiwan. Materials and Methods: In a period of 8 years, 3681 women underwent breast MRI examination in our imaging center. Of them, 95 women were known to have prior histories of cancers and were excluded from this study. The remaining breast MR images from 3,586 asymptomatic healthy women (mean age, 45.3 years) were retrospectively analyzed in this study. All subjects came to our imaging center for screening breast MR studies by self-referral due to high concern of cancer. All subjects were examined at a 1.5T scanner. The imaging interpretation was based on the criteria of ACR BI-RADS lexicon. After the breast MRI examination, complementary US was performed. If suspicious lesions were detected on MRI but showed negative results on US, double check with targeted US were done by the same radiologist immediately. US was also used to guide needle biopsy when in need. Results: Overall, among 3,586 cases, totally 115 subjects were suspected to have malignant lesions and ultrasound-guided biopsy (N=106) and/or aspiration cytology study (N=122) was performed in all these 115 subjects. 47 were proved to have malignant lesions in pathology (35 invasive cancers — 27 IDC, 7 ILC, and one apocrine carcinoma; and 12 cases of carcinoma in situ). 31 additional cases of pre-cancerous lesions were found. The mean age in cancer group was 49 y/o and 52.2 y/o in CIS group. Subjects at age 41-50 group had the highest incidence of cancer detection, including 6 in situ lesions and 19 invasive cancers. Five cases were found to have breast cancers 1 or 2 years later. The incidence for malignancy in our asymptomatic group was about 1.31% (47/3586) and increased to 2.2% (78/3586) if precancerous lesions were included. The overall sensitivity of combined US/MRI was 94% and specificity was 99%. Conclusions: Breast MRI can be an option for Asian women of average risk, who usually have dense breast, at their own cost. From our results, it was shown that combined ultrasound and MRI can achieve high sensitivity and specificity for women of average risk. The unnecessary biopsy due to the false positive diagnosis of breast MRI can also be reduced remarkably. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-02-05.