Abstract OT3-21-01: A pilot study of robot-assisted nipple-sparing mastectomy followed by immediate breast reconstruction using da Vinci SP ® single-port system

Abstract

Abstract Introduction- Robotic mastectomy is a novel breast surgery approach accessed from a concealable anterior axillary incision showing better cosmetic outcomes with a scarless front view. The oncological safety awaits further follow-up from clinical trials or registered studies to mature. Compared to older da Vinci systems with multiple arms, the new SP system is single-armed, equipped with flexible instruments and a camera that may avoid instrument collision and dead spots in the surgical field. This trial (NCT05448963) is not only the leading SP mastectomy trial in Asia but also the first one that incorporates autologous flap reconstruction. Methods- -Objectives: To determine the performance, technical algorithm, safety data, and patient-reported outcomes in single-port-accessed nipple-sparing mastectomy using da Vinci SP® system. -Study design: This study is a pilot clinical study conducted in a single-arm, non-randomized design with a goal to recruit 30 participants. The da Vinci SP ® surgical robot is applied in the nipple-sparing mastectomy and axillary lymph node dissection (if indicated) of each enrolled patient in Chang Gung Memorial Hospital Linkou Medical Center. The post-mastectomy reconstructive method may use autologous flaps or implants depending on the type of build, technical feasibility, and flap site availability of the patient. The eligibility criteria include: I. Meet at least one of the following indications of NSM for breast cancer: 1. Preoperative clinical tumor sizes less than 5 cm, with an adequate tumor-skin distance of at least 3mm and above, and without nipple-areolar involvement in at least 1cm around the nipple by image 2. Breast cancer up to stage IIIa (T3, N1-2) as the initial clinical stage showing adequate response to neoadjuvant therapy and meeting criteria 1. 3. Germline pathogenic/likely pathogenic BRCA1 or 2 mutation carriers (actionable mutations including pathogenic and likely pathogenic mutations) with a breast cancer diagnosis or requiring unilateral or bilateral prophylactic mastectomy as a risk reduction procedure II. Age equal to or above 20 years III. ECOG (Eastern Cooperative Oncology Group) performance score 0-1 IV. ASA anesthesia risk class 1~2, and with adequate organ functions Endpoint measures: -Primary endpoint: Ability to complete nipple-sparing mastectomy with da Vinci SP system in the per-protocol population. -Secondary endpoints: Safety measured by adverse events through 30-day post-operative follow up -Exploratory endpoints: Surgical time, blood loss, hospital stay, breast specimen weight, cancer resection margin, nipple-preservation rate morbidity and mortality rate within 30 days of operation, and reoperation within 30 days post-surgery -Statistical analysis: Point estimation with a 95% confidence interval will be used to analyze the mean or proportion of key performance parameters. No interim analysis will be performed due to the limited number intended to recruit. -Trial status: Active recruitment Conclusion: The single-port robotic system features single port access with multi-jointed instruments which is particularly designed for narrow surgical spaces such as mastectomy. The feasibility of applying da Vinci SP systems to robotic nipple-sparing mastectomy and robiotic axillary lymph node dissection will be demonstrated in this study. Citation Format: Wen-Ling Kuo, Chia-Huei Chu, Jung-ju Huang. A pilot study of robot-assisted nipple-sparing mastectomy followed by immediate breast reconstruction using da Vinci SP ® single-port system [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-21-01.