Benign breast 4a and malignant breast 4a modified radical mastectomy are not considered major surgeries, while radical mastectomy for breast cancer is a major surgery. 1. Benign: Generally speaking, benign breast 4a surgeries are relatively safe and simple, the operation time is not long, the risk factor is low, and it is not considered a major surgery. 2. malignant: malignant breast 4a surgery is divided into modified radical mastectomy and radical mastectomy, the former only needs to remove the tumor tissue, and at the same time the axillary lymph nodes are cleared, which is not difficult and less traumatic, and therefore is not considered a major surgery; the latter needs to carry out the whole process of general anesthesia to remove the breast, pectoralis major muscle and so on, which is more traumatic, longer and more dangerous, and belongs to the large-scale surgery. Breast 4a surgery must be carried out in specialized hospitals to avoid danger during the operation.