Oncological safety of immediate breast reconstruction with skin- or nipple-sparing mastectomy: the value of tumor-to-dermis distance measured by preoperative ultrasonography

BACKGROUND: Immediate breast reconstruction with skin-sparing (SSM) or nipple-sparing mastectomy (NSM) has become a common procedure. In this study, we evaluated the distance between breast tumor and skin in a series of patients undergoing IBR as it relates to oncologic safety, namely, the incidence of recurrence. METHODS: The distance of the tumor to the dermis, rather than the outer layer of skin, was the key parameter of our preoperative ultrasound measurements. Our data set comprised the cases of 171 patients and 181 breasts with breast cancer that had undergone two-stage breast reconstruction by expander. The median age of the patients was 47 years (25–75 years). The overall median follow-up period was 47.1 months (8.8–125.3 months). Eighty-five breasts underwent IBR with SSM/NSM; the others underwent conventional mastectomy. RESULTS: Among the total of 181 reconstructed breast mounds, the locoregional recurrence rate was 1.1% (2 breasts) with no cases of skin flap recurrence or skin flap necrosis. The tumor-to-dermis distance of cases with skin preservation (NSM/SSM) was significantly less than that of cases with conventional mastectomy (3.8 ± 2.7 mm vs 5.2 ± 2.4 mm). In cases with invasive carcinoma, all cases whose tumor-to-dermis distance was less than 2 mm underwent resection of the skin immediately overlying the tumor. CONCLUSIONS: Our results suggested that a 2-mm distance between the dermis and tumor on ultrasound evaluation is sufficient for the use of this tissue as a skin flap in SSM/NSM procedures. Our study indicated that immediate breast reconstruction with SSM/NSM can be an oncologically safe surgical option for breast cancer. However, we recommend that resection of the skin overlying the tumor be performed in cases with invasive breast cancer in which the tumor-to-dermis distance is less than 2 mm. TRIAL REGISTRATION: Patients in this study were retrospectively registered. This study design was approved by our Clinical Ethics Committee (No 1297) (http://ciru.dept.showa.gunma-u.ac.jp/guidance/storage-sample/list.html).