To Evaluate the Effectiveness and Safety of Mastectomy Combined With Immediate Breast Reconstruction in Breast Cancer

Inclusion Criteria: 1. Female patients, aged 18-75 years old; The pregnancy test (-) and reliable contraceptive methods are required for premenopausal and perimenopausal patients; 2. Patients with the diagnosed breast cancer confirmed by core needle biopsy and unilateral operation was performed; Breast cancer patients with tumor node metastasis stage 0-III according to the 8th edition of the American Joint Commission on Cancer; Preoperative clinical examination or imaging evaluation shows that the distance between the tumor and the Nipple Areolar Complex (NAC) is more than 1cm. The tumor has a diameter of 2-3 cm and can be located in any quadrant or reduced to 3 cm through preoperative neoadjuvant chemotherapy. The distance between the lesion and the skin should be at least 8-10 mm; 3. There is no clinical or imaging evidence to prove that the tumor has invaded the skin, chest wall, or nipple areola complex; 4. There are indications for breast preservation, but the patient has a strong desire for reconstruction and is unwilling to undergo breast preservation surgery; 5. Preventive mastectomy (BRCA1/2 malignant mutation with obvious family history of breast cancer and other high-risk groups); 6. Preoperative clinical manifestations and imaging data showed no distant metastasis; 7. No history of breast cancer or other serious underlying diseases in the past; 8. Karnofsky performance status score ≥ 70; 9. Eastern Cooperative Oncology Group score ≤ 2 ; 10. The surgical procedure includes endoscopic-assisted/conventional mastectomy, sentinel lymph node biopsy/axillary lymph node dissection and immediate breast reconstruction; 11. Participants are able to understand the research process, voluntarily join the study, sign informed consent forms, have good compliance, and cooperate with follow-up; 12. No swallowing difficulties; No shoulder joint movement disorders; 13. Complete clinical data. Exclusion Criteria: 1. Male breast cancer or inflammatory breast cancer; 2. Metastatic breast cancer (stage IV); Tumor invasion of the skin, pectoralis major muscle, or NAC; 3. The clinical data is basically incomplete; 4. Previously received chemotherapy in an external hospital or has undergone tumor resection in an external hospital; 5. Bilateral breast cancer surgery; 6. Other surgical methods; 7. Preoperative distant metastasis or supraclavicular lymph node dissection; 8. Complicated with other malignant tumors or had malignant tumors other than breast cancer in recent 5 years; 9. The serious disease of non malignant tumors combined will affect the patient's compliance or put the patient in a dangerous state; 10. Dementia, intellectual disability, or any mental illness that hinders understanding of informed consent forms.