Reverse-sequence endoscopic nipple-sparing mastectomy with direct-to-implant breast reconstruction and air inflation adjustment technique in breast cancer patients with large or severe ptotic breast: a single-center prospective cohort study

Background: Nipple Sparing Mastectomy (NSM) with direct-to-implant breast reconstruction (DIBR) is not recommended or even considered contraindicated in breast cancer patients with large or severe ptotic breasts (LSPB). The commonly used NSM methods for the patients are often based on the Wise-pattern skin-reducing technique, which has some shortcomings in surgical safety and breast aesthetics. The reverse-sequence endoscopic NSM (R-E-NSM) with DIBR and the air inflation adjustment technique (AIAT) have shown promising clinical outcomes for breast cancer patients. This study aimed to evaluate the safety and aesthetic outcomes of the R-E-NSM with DIBR and AIAT in breast cancer patients with LSPB and to investigate the feasibility of NSM with DIBR in the patients. Method: The prospective study enrolled breast cancer patients who underwent R-E-NSM with DIBR from September 2020 to August 2024 at a single institution. According to whether the suprasternal notch to nipple distance was over 25 cm or the mastectomy weight was over 600g, patients were categorized into the LSPB group and the NLSBP group. The propensity score matching (PSM) was used to balance the baseline characteristics between the two groups. Then, the surgical safety, aesthetic outcomes, and oncologic safety were compared between the two groups. Findings: A total of 563 patients were included (LSPB n=98, NLSPB n=464). After PSM, there were 88 and 256 patients retained in the LSPB and the NLSPB groups (mean [SD] age: 42.6 [9.4] vs. 42.7 [8.3] years, median [IQR] follow-up time: 21.0 [13.8, 32.4] vs. 23.0 [10.6, 32.2] months). The mastectomy weight of the LSPB and the NLSPB groups was 576.6±144.8 g and 330.1±105.7 g, respectively (P<0.001). There were no significant differences in any complications (27.3% vs. 22.7%, P = 0.381), major complications (6.8% vs. 3.1%, P = 0.230), minor complications (20.5% vs. 21.1%, P = 0.889) and implant-related complications (21.6% vs. 25.0%, P = 0.519) between the LSPB and the NLSPB groups. With AIAT, the Ueda scores in the NLSPB group were better than those in the LSPB group (P = 0. 038). In the LSPB group, the Ueda scores in patients with AIAT were significantly better than those without AIAT (P=0.021), and similar to those of the NLSPB group without AIAT (P = 0.526). The two groups had no significant difference in the breast-Q scores (all P>0.05). The oncologic outcomes had no significant difference between the two groups (all P>0.05). Interpretation: R-E-NSM with DIBR and AIAT can bring favorable surgical safety for patients with LSPB with no significant difference from patients with NLSPB, which offers a new or superior option for breast cancer patients with LSPB beyond the NSM with Wise-pattern skin-reducing technique.