Precision Breast Conserving Surgery With the Guidance of Localization Combined With Multidetector CT 3-dimensional Image Reconstruction: a Single Center, Prospective, Cohort Study.

Background Breast conserving surgery (BCS) with radiation is accepted as a standard local treatment for early-stage breast cancer. This is largely based on the results of NSABP B-06 trial， demonstrating no significant difference in survival among patients who received total mastectomy or lumpectomy [1]. More recent studies showed that the overall survival was superior for BCS compared with mastectomy [2,3,4]. Furthermore, long-term quality of life (QoL) was better in patients treated with BCS than with mastectomy [5]. Advantages in survival and QoL have led to a higher demand for BCS.

Success of BCS is characterized by negative margins and a good cosmetic outcome. This requires doctors to precisely remove the tumor while preserving as much normal tissue as possible. Current guidelines strongly recommend achieving "no ink on tumor" for invasive breast cancer (IBC) . More widely clear margins do not significantly decrease the rate of ipsilateral breast cancer recurrence (IBCR) [6]. However, conventional localization techniques only provide approximate tumor center and fail to provide tumor extents [7]. In clinical practice, doctors may remove more tissue to achieve negative margins and avoid a reoperative intervention. Among the patients treating with BCS, 30% survivals were dissatisfied with the cosmetic outcome [8].

Wire-guided localization (WGL) is a feasible, widely used technology used for the localization of nonpalpable breast lesions prior to surgical management. The flexible self-retaining wire can be inserted into the exact lesion guided by ultrasound (US) or mammography. The surgeon than uses the wire as a guide to excise the lesion [9]. At the same time, the metal needle is visible under CT. The role of multidetector CT (MDCT) is limited in the diagnosis of breast tumors [10,11]. However, MDCT has many unique advantages. First of all, patients are in the supine position during MDCT scan, which is consistent with the surgical position. Secondly, MDCT is effective for the detection of tumor extension [12]. Beside, MDCT is convenient for 3-dimensional (3D) reconstruction. MDCT guided 3D reconstruction has been widely used in clinic, including surgery guidance. Therefore, we speculate that WGL combined with MDCT can be helpful for precision breast conserving surgery (PBCS).

The aims of this cohort study were to determine whether WGL combined with MDCT guided 3D reconstruction could guide PBCS, and to access the cosmetic outcome reported by patients.

Study Design We did a single center, prospective, cohort study in one group of our department from August 2021 to June 2022. The treatment for all patients were discussed by the multi-disciplinary team in our center. The decision in this study was decided by shared decision-making between patients and multi-disciplinary teams. All procedures for the enrolled patients were performed by one surgeon. All CT images were processed by an experienced radiologist. All specimens were evaluated by two experienced pathologists.