Purpose: Oncologic and surgical outcomes of robot-assisted nipple-sparing mastectomy (RNSM) compared to conventional nipple-sparing mastectomy (CNSM) is under investigation. This study compared the clinical outcomes of recurrence-free survival and postoperative complication after RNSM and CNSM. Materials and Methods: We retrospectively reviewed data of 401 patients who underwent da Vinci Si/Xi/SP-assisted RNSM or CNSM with immediate reconstruction between November 2016 and November 2020 at a single institute. Oncological outcomes were collected until March 2022. Primary endpoints were long-term outcomes, such as local recurrence, distant metastasis, disease-free survival, overall survival, and postoperative complications, while secondary endpoints were pathology results, and oncological outcomes. Results: Patients underwent RNSM (n=162) or CNSM (n=239). Of RNSM cases, 9 (5.6%) were performed using the da Vinci Si System, 96 (59.3%) using the da Vinci Xi System, and 57 (35.2%) using the da Vinci SP System. No significant difference in recurrence-free survival was found between the RNSM and CNSM group, and both groups had a median follow-up of 37 months. The recurrence rate in RNSM patients after a median follow-up of 24.5 months was 3.8%, compared with 5.9% in CNSM patients after a median follow-up of 42 months. No difference in recurrence was seen among RNSM patients with respect to surgical systems (multiport vs. SP, p =0.136). In addition, grade III postoperative complication rate was lower in patients with RNSM than in those with CNSM. Transfusion was only applied in 6.2% of patients. Conclusion Robot-assisted surgical systems can be safely used to perform nipple-sparing mastectomy in patients with early breast cancer.

Purpose: High incidence of osteoporosis has been reported in breast cancer patients due to early menopause triggered by adjuvant treatment and temporary ovarian function suppression. In this study, we sought to determine whether long-term breast cancer survivors had an elevated risk of low bone density compared to the general population. Methods: Long-term breast cancer survivors who had been treated for more than 5 years were selected for this study. Data were obtained from medical records and using a questionnaire from the Korea National Health and Nutrition Examination Survey (KNHANES). An agematched non-cancer control group was selected from the KNHANES records. Incidence of fracture and bone mineral density (BMD) were compared between the two groups. Results: In total, 74 long-term breast cancer survivors and 296 non-cancer controls were evaluated. The incidence of fracture did not differ between the two groups (P=0.130). No differences were detected in lumbar BMD (P=0.051) following adjustment for body mass index, while hip BMD was significantly lower in breast cancer survivors (P=0.028). Chemotherapy and endocrine treatment were not related to low BMD in breast cancer survivors. In more than half of the survivors, the 10-year risk of osteoporotic fracture was less than 1%. Conclusion Long-term breast cancer survivors had low bone density but a comparable risk of fracture compared to non-cancer agematched controls. Further studies on the factors related to low bone density in long-term breast cancer survivors are required.