Breast cancer is one of the main malignant tumors threatening women's lives. In recent years, the increasing demand for reconstruction of breast cancer patients in China has made the proportion of breast reconstruction increase year by year, while implant reconstruction has become the most important way of breast reconstruction due to its less injury, shorter time of operation and relatively simple surgical technique. In the long-term clinical practice, due to the lack of safe and effective alternative methods, the reconstruction method with prosthesis placed to posterior pectoralis major has been accepted by surgeons and patients, and has become the most commonly used method of prosthesis construction. However, the development of biomaterials provides new ideas for breast reconstruction. At present, more and more doctors in clinical practice discontinue the use of serratus anterior, but use the synthetic mesh (mostly titanium mesh TiLoop® Bra) or allogeneic acellular dermal matrix mesh to cover part of the dilator or prosthesis so as to shorten the entire operation cycle and make the appearance of the reconstructed breast more natural and aesthetic. In particular, it can improve the contour of the folds under the breast and shape the breasts with a certain degree of sagging.

This study takes the patients receiving immediate reconstruction with an implant combined with TiLoop® Bra after total mastectomy as the subjects, aiming to compare the aesthetics and safety of the placement of implant to anterior and posterior pectoralis major through a prospective and randomized study. The primary objective of the study is to analyze the aesthetics of breast appearance, patient satisfaction and postoperative quality of life (QOL) of the placement of implant to anterior and posterior pectoralis major. The secondary objective of the study is to analyze the incidence of complications and type of reoperation in both groups.

Inclusion Criteria:

1. More than 18 years old
2. Female
3. Preoperative pathology confirming invasive breast carcinoma or ductal carcinoma in situ
4. Clinical T1 and T2 (Maximum tumor diameter ≤5 cm)
5. Clinical ALN negative (Clinical physical examination and ultrasound indicate axillary lymph node negative; Suspected abnormality of axillary lymph node, and fine needle aspiration negative)
6. No clinical or imaging evidence of distant metastasis
7. Patients to receive skin sparing mastectomy or nipple sparing mastectomy
8. BMI < 35
9. Patients with no or mild mastoptosis
10. Prosthesis to be implanted <500 ml
11. Be able and willing to sign the Informed Consent Form (ICF)

Exclusion Criteria:

1. Patients with the breast of moderate-severe mastoptosis, or requiring the use of Wise-pattern or other breast lift methods for subcutaneous mammary gland resection
2. BMI>=35
3. Patients who have received symmetrical breast surgery on the unaffected side immediately or later
4. Patients with locally advanced breast cancer to receive neoadjuvant therapy
5. Patients currently participating in other clinical trials, which may have impact on the participation in this trial
6. Neoadjuvant therapy has been completed, and there is clear indication of adjuvant radiotherapy after the operation
7. Previous history of breast cancer (patients with ipsilateral recurrence after breast sparing surgery)
8. Pregnancy breast-feeding women
9. History of smoking
10. Previous history of diabetes

Undecided