Qiang Ding

Background: Gynaecomastia (GNY) is the most common benign proliferation of glandular breast tissues in males and is frequently associated with psychosocial distress and aesthetic concerns. Traditional open surgical approaches are associated with visible scarring and prolonged postoperative recovery. Minimally invasive techniques, including liposuction-assisted endoscopic procedures, may still result in visible scars and residual glandular tissue. In this study, we evaluated the safety, efficacy, and aesthetic outcomes of endoscopic subcutaneous mastectomy combined with cold-knife flap dissection through a single axillary incision for the treatment of GNY. Methods: A total of 51 male patients with GNY involving 102 breasts who underwent surgical treatment between August 2023 and October 2024 were enrolled. Patient demographics, operative data, postoperative complications, and satisfaction outcomes were systematically recorded. Four independent observers evaluated preoperative and postoperative photographs using a 1–15 scoring system based on six major aesthetic parameters. Results: Endoscopic subcutaneous mastectomy combined with cold-knife flap dissection through a single axillary incision was successfully completed in all patients. The mean operative time was 46.84 ± 15.04 per side (range 14–87) min. The mean thickness of the resected glandular tissues was 2.80 ± 0.88 (range 1–5) cm. The mean postoperative drainage volume was 48.72 ± 34.74 (range 10–170) mL, and the mean hospital stay was 4.31 ± 1.57 (range 2–8) days. Postoperative complications included hematoma in two breasts, seromas in one breast, and effusion in two breasts, whereas skin redundancy occurred in two patients with bilateral GNY. No patient developed severe pain, infection, nipple–areolar complex necrosis, nipple retraction, or skin flap necrosis. All patients reported satisfaction with postoperative quality of life (100%), and no recurrence was observed during follow-up. Conclusions: Endoscopic subcutaneous mastectomy combined with cold-knife flap dissection through a single axillary incision appears to be a safe and effective approach for GNY, offering minimal invasiveness, rapid postoperative recovery, and favourable aesthetic outcomes. This technique may improve patient satisfaction and may represent a promising treatment option owing to its favourable safety profile and cosmetic outcomes. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Figure S1 illustrates the mRNA expression levels of additional key members of the FA pathway.

Figure S3 shows FANCI overexpression facilitates the proliferation of breast cancer cells.

Figure S4 shows FANCI overexpression enhances breast cancer cell migration ability.

Figure S6 displays the results of Human PARP1 ELISA assays after nuclear-cytoplasmic separation and the impact of FANCD2 expression changes on PARP1 functionality.

Figure S7 illustrates the enhanced sensitivity of breast cancer cells to talazoparib by FANCI knockdown.

Figure S8 showcases the combination effect of talazoparib and palbociclib, as well as the influence of FANCI overexpression on this combination.

Table S1-4 contain the specific sequences and information of Primers used for Quantitative RT-PCR, shRNA, siRNA, and Flag-tagged plasmids.

Figure S5 presents a comprehensive analysis of the interaction between FANCI and PARP1.

Figure S2 depicts the expression patterns of FANCI among breast cancer patient groups based on clinical parameters.