Abstract:

Ductal carcinoma in situ (DCIS), a pathological type of breast cancer that is limited to the terminal ducts of the breast without breaking through the basement membrane, is considered as the precursor of invasive ductal carcinoma (IDC). When DCIS breaks through the basement membrane and invades surrounding tissues, it can form infiltrating lesions. If the maximum diameter of a single infiltrating lesion is less than 1mm or the maximum diameter of multiple infiltrating lesions is less than 1mm, it is defined as ductal carcinoma in situ with microinvasion (DCIS-Mi). About 12%-40% of untreated and intervened DCIS will progress to IDC, and DCIS and IDC can also coexist. However, there is a considerable portion of DCIS that never progresses with good prognosis. Recently, overdiagnosis and overtreatment of DCIS have become the research hotspots. The histological grade of DCIS is mainly based on the morphology of the nucleus, which is divided into three nuclear levels: low, medium, and high. There are also significant differences in receptor expression and molecular type distribution between DCIS, DCIS-Mi, and IDC. For DCIS with or without microinvasion as well as different histological grades, there are many controversies about the treatment regimen, clinical prognosis and risk. The development of modern imaging technology has achieved preliminary evaluation of histological grading, infiltration status, and prognosis prediction of DCIS. The most commonly used breast imaging techniques in clinical practice currently include mammography (MG), ultrasound (US), and magnetic resonance imaging (MRI). The imaging principles of these three techniques are different, and each has its own advantages and disadvantages in breast disease imaging diagnosis. However, they can complement each other and play an important role in disease diagnosis, treatment, and prognosis evaluation. Mammography has the advantages of safety, reliability and good repeatability. It is the preferred screening method for breast cancer recommended by international guidelines. The main manifestations of DCIS on MG can be divided into non calcified lesions and calcified lesions. On US, the main manifestations are lesions and non-lesion type, which can be further divided into hypoechoic changes, calcification, ductal changes, and structural disorders and distortions. MRI has higher sensitivity in detecting DCIS without calcification and multifocal DCIS compared with MG, and has higher accuracy in evaluating the lesion range. However, there are also shortcomings such as low diagnostic specificity and insensitivity to microcalcification display. In addition, radiomics has great potential in the histopathological evaluation, prediction, and guidance of individualized precision treatment of DCIS. In the current era of precision medicine, image features, histopathology, molecular genes, etc. are increasingly significant in predicting the prognosis of breast cancer. The early accurate diagnosis and molecular type of DCIS are also extremely important in clinical work. It has become a consensus in clinical treatment to predict the potential benefits of different treatments through molecular typing, histological grade, and imaging findings, in order to develop the most suitable personalized treatment plan. This article reviewed the correlation between imaging features and the molecular subtype, histopathology and prognosis of DCIS.

Key words: Ductal carcinoma in situ, Mammography, Ultrasound, Magnetic resonance imaging, Radiomics