Early stage breast cancer mainly refers to carcinoma in situ, which is an early stage of the disease, and it is possible to cure the lesion by confirming the diagnosis of the disease and surgical treatment. Breast cancer is a malignant tumor originating from the epithelial cells of the breast, and in the early stage of the disease, the lesions are limited, and when breast ultrasound is performed, it is possible to find nodules inside the breast, or it may not be possible to find nodules. When a mammogram is performed, it is possible to detect punctate calcified foci inside the breast. Carcinoma in situ is an early stage of breast cancer. If the lesion can be detected and diagnosed, it may be cured by complete removal of the lesion through surgery, and subsequent endocrine therapy, targeted drug therapy, and other measures based on the type of pathology, immunohistochemistry, and genetic testing after surgery. Since breast cancer occurs mostly in the female population, regular ultrasound and molybdenum target examinations are necessary for the female population. During the examination process, if you find any internal nodules or calcified foci, you must be vigilant, and for patients with diagnostic difficulties, early pathologic examinations are conducted to avoid missed diagnosis of breast cancer and other malignant lesions.