Breast CT: Its Prospect for Breast Cancer Screening and Diagnosis

摘要

Mammographic screening has led to a substantial reduction in breast cancer mortality during the past 20 years (1-4). This reduction in mortality is an important step toward lessening the burden of breast cancer, but most breast imaging experts acknowledge that mammographic screening has limitations, especially in women with dense breasts (5). For example, Figure 1 illustrates the results of an ideal observer performance evaluation (a computer simulation), which shows sensitivity as a function of breast lesion diameter for five categories of breast density (6). These curves were generated for an assumed specificity of 90%. The data demonstrate that for women with mostly adipose breasts (breasts with low breast density), there is a 60% probability that a breast cancer will be discovered when it is about 4 mm in diameter. Women with dense breasts, however, will have to wait (on average) until their cancer grows to 17 mm in diameter for equivalent detection performance (ie, 60% sensitivity). This delay in detection corresponds to about 1.7 years of tumor growth, assuming a 100-day in vivo tumor doubling time (7). These results, although they are based on simulations, do mirror the qualitative experience of most radiologists who specialize in breast imaging. Clearly, more can be done to improve breast cancer screening performance in women with dense breasts.