Breast cancer pathology grade III means that the breast cancer cells are less differentiated, the tumor cells are more malignant, and the prognosis is worse compared to grade I and grade II breast cancer. The absence of cancer cells at the edge of the incision indicates a clean resection. In the pathology report of breast cancer, doctors usually grade the breast cancer according to the pleomorphism of the nuclei of the cancer cells and the nuclear division term, which are grade 1, grade 2 and grade 3 respectively. The higher the grade, the more malignant the tumor cells are, and the more likely the cancer cells are to metastasize to lymph nodes or to distant organs such as lungs and liver and brain tissue. Grade III breast cancer pathology indicates high malignancy and poor healing. The absence of cancer cells at the edge of the incision indicates that the tumor is locally excised cleanly and there is no cancerous tissue left, which means that the surgical result is very good. After mastectomy, more aggressive treatments need to be given to delay postoperative recurrence. When a patient develops breast cancer, he/she needs to go to a specialized hospital to seek professional medical consultation.