Puncture smear or biopsy of breast lesions is mainly used for those who are reluctant to do excisional biopsy due to the failure of other examination methods to characterize the lesions. It has been suggested that this method can cause the spread of cancer cells and local implantation of tumor cells, which is theoretically valid. However, no one has reported an increase in the rate of systemic cancer metastasis due to the identification of cancer by puncture of breast tissue. Since malignant tumor tissues have rich blood circulation and lymphatic drainage, any injury and stimulation may cause tumor cells to spread and metastasize along the blood vessels and lymphatic vessels, no matter it is a puncture cytology or histology examination, and no matter the thickness of the needle, it is always an injury examination. Therefore, it is inevitable that the tumor cells may spread, but puncture is after all less harmful than partial excision of the mass, which is convenient and safe, and has a high diagnostic rate. After puncture, if the tumor is confirmed to be malignant, surgery should be performed as soon as possible, preferably in less than 1 week and no later than 2 weeks. If surgery cannot be performed in time due to other reasons, chemotherapy can be given first to prevent the spread of cancer cells.