A Pilot Study of Robot-assisted Nipple-sparing Mastectomy Followed by Immediate Breast Reconstruction Using da Vinci SP ® Single-port System

About 49% of breast cancer surgery is managed by total mastectomy, and half of the patients undergo breast reconstruction. Nipple-sparing mastectomy (NSM) is indicated for breast cancer requiring total mastectomy and without nipple involvement by cancer. The local recurrence rate is not increased and the cosmetic result much improved. Robot-assisted mastectomy utilizes surgeon-controlled robotic arms with delicate, multi-jointed instruments and 3-dimentional high-definition camera in place of conventional instruments under bare eye vision. Through a single longitudinal incision in the anterior axillary line at the nipple areolar level, the lesion and the whole breast tissue can be totally removed with negative resection margins and well-preserved breast skin envelope. Breast reconstruction can be successfully performed through the same incision and results in a scarless front view. Currently, this surgery is effectively carried out with da Vinci Xi system. However, the small incision may result in the collision of robotic arms outside the torso and hence decreases the range of instrument motion. The next-generation robot, da Vinci SP system, is single-armed, equipped with multiple flexible instruments and camera, which are devoid of outside collision and allows work in a larger surgical field through the same small incision. The SP system reduces blind areas in the surgical field and the blockade of camera vision by the detached space-taking specimens, and, therefore, will hopefully reduce the surgical time. The investigator's scope of this study is to establish the feasibility and safety of SP-applied NSM through this single-armed pilot trial. The investigators recruit breast cancer women indicated for nipple-sparing mastectomy or candidates of prophylactic mastectomy carrying germline pathogenic or likely pathogenic BRCA1/2 mutations to receive SP-assisted unilateral or bilateral NSMs. Immediate breast reconstruction is followed according to the mode of the plastic surgeon's clinical decision. The primary endpoint is technical feasibility (conversion rate, surgical time), and the secondary endpoint is safety and patient-reported outcome.