Inclusion Criteria:

• 1) Aged 18 or above; 2) Breast cancer confirmed by core needle biopsy; 3) Tumor lesions clearly visible on ultrasound; 4) No contraindications for cryoablation such as coagulation disorders; 5) Presence of reasons unsuitable for conventional surgical resection: patient's condition cannot tolerate general anesthesia or surgical treatment; due to unresectable and/or metastatic disease; patient refuses surgery, etc.; 6) Agree to undergo ablation surgery and sign the consent form.

Exclusion Criteria:

• 1) Missing clinical and pathological data (such as imaging and pathological materials); 2) Pregnant or lactating women; 3) Known allergies, intolerances, or contraindications to cryotherapy (such as cryoglobulinemia, presence of implanted electronic devices); 4) Vulnerable populations, including those with neurological disorders, cognitive impairments, critically ill patients, etc.