Surgical and Oncologic Outcomes After Robotic Nipple Sparing Mastectomy and Immediate Reconstruction

This study is an international multi-center pooled analysis using prospective and retrospective studies to evaluate surgical and oncologic outcomes of robotic nipple-sparing mastectomy with immediate reconstruction.

Raw data for robotic or conventional nipple-sparing mastectomy from Severance Hospital, Samsung Medical Center, the European Institute of Oncology, Changhua Christian Hospital, and Gustave Roussy is collected. Among them, Severance Hospital takes the lead at performing analysis from the data. Storage and disposal of patients' records are managed by each researcher. In the analysis process, although the collaborators can request records from Severance Hospital if necessary, they are only supposed to be provided computerized data which were originally clinical data from patients who already ended treatments. In this case, individual identifying data and medical records are not shown.

Clinicopathologic variables including operation times, hospital stay, medical history, smoking history, family history, BMI, menopausal status, specimen weight, TNM stage, grade, histological type, estrogen receptor, progesterone receptor, HER2, Ki 67, and perivascular involvement are analyzed.

Postoperative complications within 30 days are collected and classified by the Clavien-Dindo grade. Locoregional recurrence-free survival and local and systemic recurrences are examined. Patients whose data have been retrospective for at least one month are to be examined.

Patient's and surgeon's satisfaction using Breast Q is evaluated. Categorical variables are examined using the chi-square test or Fisher's exact test if indicated.

Continuous variables are examined using the independent t-test or ANOVA if indicated.

The estimated sample size from the four institutions is about 300 cases for robotic nipple-sparing mastectomy and matched cases for conventional nipple-sparing mastectomy.

Propensity matching analysis is applied to reduce confounding factors.

Inclusion criteria

• Women who underwent nipple sparing mastectomy and immediate reconstruction
• Women with early breast cancer
• Women with germline BRCA 1/2 mutation or germline mutations in genetic susceptibility genes
• Women with interstitial mastopathy
• Women with risk-reducing mastectomy or contralateral mastectomy

Exclusion criteria

• Male patients
• Women with stage IV disease at diagnosis
• Women who underwent previous breast cancer surgery
• Women who received prior radiotherapy for the ipsilateral breast