Breast cancer 4C belongs to the advanced stage of breast cancer. 4C, which appears in the breast imaging report, is one of the types of BI-RADS grading. BI-RADS grading is a method to assess the degree of benign and malignant breast by imaging, which is divided into 0-6 grades, and the possibility of malignancy increases with the grade. Among them, 4C represents a 61%-94% possibility of malignancy, but not all 4C patients are necessarily cancerous, and need to be combined with physical examination, laboratory tests and puncture biopsy pathology to make a comprehensive judgment. Breast cancer 4C is equivalent to stage IV in TNM staging. Patients will not only have peripheral axillary and clavicular lymphatic metastases, but also have metastases to other organs, and patients’ prognosis is poor and survival time is relatively short. Due to the increasing social pressure, the incidence of breast cancer has increased and the age of onset has also advanced. Women are advised to have regular breast examinations to facilitate early detection and early treatment.