Improving the Accuracy of Screening Dense Breasted Women for Breast Cancer By Combining Clinically Based Risk Assessment Models with Ultrasound Imaging

The report by Gao et al., provides results to support important implications about breast cancer screening in China and illustrates several potential approaches for implementing strategies for dealing with screening women with dense breasts in general. In order to fully appreciate the scope and clinical impact of the study reported by Gao et al. ( ), it is important to briefly review the evolution of breast cancer screening in China. In 2014, Fan et al. ( ) reviewed the characteristics of breast cancer in China. They began their review with the statement that China was the largest middle to low-income country in the world. They went on to describe the socioeconomic diversities, epidemiological factors, and disparities to access to healthcare across China that provide a context for understanding the motivations and practical considerations for establishing effective national breast cancer screening programs. As pointed out by Fan et al. ( ), and Chen et al. ( ), the incidence of breast cancer has been increasing in China over the past three decades. Accordingly, the Chinese government launched a three year Cancer Screening program in 2009, the Two Cancer Screening Program Campaign (Breast and Cervical cancer), to provide free breast cancer screening initially to 1.46 million rural women, and extended that program for an additional three years to six million rural women in 2012 ([4]).The choices of imaging modalities for screening were influenced by the fact that Chinese women tend to have small and dense breasts ( ) which has a negative impact on the diagnostic accuracy of screening mammography. Ultrasound was chosen as the primary screening method because it has clear diagnostic advantages over mammography in dense breasted, younger Chinese women ([4]). Because there had been few direct comparisons of the accuracies of screening for breast cancer using ultrasound or mammography, in 2015, Shen et al. ( ) carried out a large, prospective, randomized breast cancer screening trial. The results demonstrated superior diagnostic accuracy for ultrasound. More recently, An et al. ( ) reported a comparison of the results of breast cancer screening of a high-risk population of Chinese women with ultrasound and mammography. These authors reported fewer inconclusive results with ultrasound in BI-RADS score 0. In cases with BI-RADS score two and a histologically confirmed diagnosis of benign breast lesions the methods were equivalent. In cases with BI-RADS score four and a histologically confirmed diagnosis of breast cancer, the sensitivity of breast ultrasound was higher than mammography 0.989 and 0.859, respectively. In cases with BI-RADS score five and a histologically confirmed diagnosis of breast cancer the sensitivities of breast ultrasound and mammography were 1.000 and 0.984, respectively. Even though the diagnostic performance of screening ultrasound was shown to be high in these and other studies, it is important to remember that the large population of China and the need for regular screening for the early detection of breast cancer translates into a large number of annual screening examinations and this requires extremely high sensitivity and specificity of diagnosis to order to minimize both the number of false positive and false negative results at screening.