Recruitment has been temporarily suspended since the start of the pandemic due to the need for travel for this study. Will resume when appropriate.

Nipple-sparing mastectomy (NSM) with immediate reconstruction is one of the standard of care surgical treatments of breast cancer (BC) and is used for risk reduction in patients with a high risk for BC. While this method shows satisfactory oncologic and good cosmetic outcomes, its drawbacks include compromise of the skin flap vascularization due to skin incision, nipple-areolar complex (NAC) malposition/distortion and visible scar on the breast. NSM also has technical challenges of dissecting and removing larger specimens through limited incisions and concerns regarding oncologic effectiveness due to difficulties in visualizing regions of the breast remote from the incision. To improve cosmetic outcomes after NSM, a modification of this technique using a surgical robotic system was recently described. In a limited number of studies, the robotic NSM (RNSM) with immediate prosthetic breast reconstruction (IPBR) was shown to be feasible and safe, as well as led to excellent cosmetic outcomes and patient satisfaction. There are limited number of centers in North America and none in Canada that offer RNSM-IPBR. The investigators hypothesize that RNSM-IPBR is a feasible and safe technique that can be utilized in our institution and that it can provide superior cosmetic outcomes with less morbidity and higher patient satisfaction compared to the traditional NSM-IPBR. The aim is to conduct a single-arm prospective study to investigate the safety and feasibility, as well as cosmetic, surgical complication and patient satisfaction parameters of NSM-IPBR performed in the University Health Network (UHN). This study will serve a foundation for potential introduction of a novel surgical approach in our institution and will make it available for treatment and prevention of breast cancer in Canadian women. The study will also serve as pilot data for future potential studies, including randomized-controlled trials (RCT) comparing RNSM with conventional NSM. As such, the study will further our approach to innovation in breast surgical oncology within Canada and North America.

This is a single-arm prospective study to assess feasibility and safety (primary outcomes), as well as patient satisfaction, cosmetic and oncologic outcomes of RNSM-IPBR in women with BC or at high risk of BC treated at UHN.

The objectives of the study are to determine:

1. Feasibility of RNSM-IPBR through assessing operative parameters (such as time of procedure, robot docking time, conversion to conventional NSM-IPBR).
2. Safety of RNSM-IPBR through assessing rate of morbidity from surgical complications (such as wound infection, flap and NAC necrosis, postoperative hematoma/bleeding, seroma requiring aspiration, implant loss, anesthesia related complications and need for reoperation with one month due to complications) and mortality due to the procedure.
3. Patient satisfaction from RNSM-IPBR through assessing psychological, physical, sexual well-being, as well as satisfaction with breast, overall outcome and care through patient reported outcomes.
4. Cosmetic outcomes of RNSM-IPBR, such as distortion or malposition of NAC and scarring, rate of reoperation due to unacceptable cosmetic outcomes.
5. Short- and long-term oncologic outcomes of NSM-IPBR, such as positivity of margins, breast cancer incidence and recurrence rate, as well as overall survival.

The rationale of the study is to investigate a novel technique of RNSM-IPBR that might have superior cosmetic and patient satisfaction outcomes, as well as lower rates of complications, based on a small number of previously published studies from Europe and Asia.

Once enrolled, clinical, radiologic, and pathologic data will be collected for each participant at the initial visit and follow up data will be collected via available electronic patient records.

RNSM-IPBR will be performed by previously described method (Toesca et al.) using an extra-mammary axillary incision along the mid-axillary line in the axillary fossa. We will use Da Vinci Si Surgical System® (Intuitive Surgical, Sunnyvale, CA) available at Toronto General Hospital, UHN.

Inclusion Criteria:

• Women of any age with invasive breast cancer (BC), ductal carcinoma in situ (DCIS), BRCA or other breast cancer genetic mutation carriers or high risk BC female patients who are otherwise candidates for NSM with IPBR will be eligible for the study. For those patients, RNSM-IPBR will be offered. Those who, after thorough discussion of risks and benefits, choose and consent to undergo RNSM-IPBR will be included in the study.

Exclusion Criteria:

• Heavy smokers (>20 cigarettes a day)
• Uncompensated Diabetes Mellitus
• High risk for anesthesia (ASA 4)
• Inflammatory Breast Cancer
• Previous thoracic radiation therapy for any reason
• Pregnancy
• Psychiatric, addictive, or any disorder which compromises ability to give informed consent for participation in this study

Female patients with increased lifetime risk of breast cancer Female patients with early stage breast cancer