Breast cancer is a common malignant tumor in women, because the tumor is located on the surface of the body, it also provides a convenient advantage for early detection and diagnosis of breast cancer compared to other tumors. Medical experts have been working on the improvement and innovation of various diagnostic methods and instruments to make a better basis for early detection, diagnosis and treatment of breast cancer. So how can women know the early detection and diagnosis of breast cancer and what tests can be done to help them? Self-examination of breast: Although many advanced equipment and examination methods have emerged and innovated to provide a reliable basis for early detection and diagnosis of breast cancer, there is no method that is simpler, easier, more economical and more effective than self-examination, which is suitable for women of all ages. After menopause, women can fix one day a month to do self-examination, it is best to make a record each time, to facilitate future comparison and observation. 2.Mammography: It is one of the best methods to diagnose breast cancer. Because the image is clear and intuitive, it is not influenced or interfered by the examiner’s technique and other factors, which can help the early diagnosis of breast cancer. Calcifications in breast cancer are usually mud-like, stick-like, or irregular, small gravel-like, and sometimes may form small linear or bifurcation-like calcifications along the ducts. It is suitable for women over 40 years old, people with high risk factors and patients whose tumors cannot be ruled out by other examinations, and can be examined once a year or once every two years. For women under 40 years old, it is not easy to detect lesions due to dense breast tissue and sensitive to radiation absorption, which increases the incidence of breast cancer, so try to have mammogram examination when it is not necessary. Ultrasound examination of the breast is easy, quick, non-invasive, non-damaging, and can be repeated several times for review. It can determine whether there is a lump in the breast, its size and location, identify whether it is cystic or solid, whether it is accompanied by blood flow signals, etc. It can improve the differential diagnosis of benign and malignant tumors, but for smaller diameter nodules, the ability to identify them is limited, and interference by technical factors of the operator or for some lesions that only have structural changes in the breast, it is necessary to combine with other examinations to make a clear diagnosis. Breast ultrasound is suitable for women of all ages and different physiological periods, especially for young women and those with dense breast tissue, etc. Although breast ultrasound can be done at any time, it is better to examine within 3-7 days after menstruation. Ductoscopy: Ductoscopy is a special examination for suspicious lesions in the milk ducts, which is roughly the same as gastroscopy, and can directly observe the lesion location and size, and for some suspicious lesions, cytological examination can be performed under the ductoscope with biopsy needle or biopsy forceps, which is of great value for the diagnosis of early breast cancer, and for some non-tumor inflammatory diseases, it can play a therapeutic role through ductoscopic irrigation. The ductoscopy is suitable for women of any age, mainly for patients with non-lactating nipple discharge, especially for patients with single-hole nipple bloody and plasma overflow and clear water-like overflow. MRI of the breast: MRI has high resolution of soft tissue, high value for benign and malignant lesions, and no radiation, and high sensitivity for detecting breast lesions, especially for observing tumors in the dense breast which are more difficult to evaluate by x-ray, local recurrence of breast cancer after surgery and whether there are tumors left in the breast tissue after mammaplasty and observing the location of prosthesis, whether there are missed or It is more sensitive to the presence of chest wall invasion and lymph node metastasis in the axilla and posterior sternum, and can help to provide a basis for accurate staging and treatment plan of breast cancer. In addition, it is a complex, time-consuming and costly test, and there is a certain overlap between the performance of benign and malignant lesions in MRI, so it is not usually used as a routine test in clinical practice.