Minimal incision-assisted endoscopic versus conventional open breast-conserving surgery: A multicentre randomized clinical trial

Background: Compared with conventional open breast-conserving surgery (BCS), conventional endoscopic (E-BCS) mostly involves dual incisions, which provide an insignificant scarring benefit but increase the surgical difficulty and prolong the surgical time. In contrast, the novel minimal incision-assisted E-BCS (M-E-BCS) procedure enables a near-scarless operation with efficient and precise tumour resection through a single axillary incision. Methods: This is a phase III, open-label, multicentre, superiority, randomized controlled trial conducted in 3 class IIIA hospitals in China. Patients were assigned to M-E-BCS or conventional open BCS (C-O-BCS). The aim was to compare aesthetic outcomes, surgical efficiency, and safety. The primary endpoint was the patient-reported SCAR-Q score for scar appearance satisfaction at 18 months postoperatively. Secondary endpoints included aesthetic outcomes, quality of life (QoL), operative time, complications, and oncologic outcomes. Results: Overall, 163 patients were analysed, with 82 in the M-E-BCS group and 81 in the C-O-BCS group. The 18-month SCAR-Q score was available for 155 patients (8 missing, 4 per group). M-E-BCS demonstrated superior SCAR-Q scores (79.9 ± 9.5 vs. 61.4 ± 17.4, P < 0.001), greater improvement in BREAST-Q breast satisfaction (17.7 ± 18.2 vs. 5.4 ± 21.5, P < 0.001), and better psychosocial well-being (10.1 ± 19.2 vs. 0.1 ± 19.3, P = 0.001) at 18 months. The physician assessment (Ueda score) showed a higher “excellent” rate for M-E-BCS (86.5% vs. 57.9%). Operative time (130.8 ± 37.9 vs. 121.8 ± 30.5 min, P = 0.167), complication rates (11.0% vs. 13.6%, P = 0.612), and short-term oncologic outcomes were not significantly different between groups. The median follow-up was 30.0 months (range 19.0–45.0 months). One patient in the C-O-BCS group developed bone metastasis at 5 months, and another developed axillary lymph node recurrence at 17 months. No local recurrence or death occurred in either group. Conclusion: M-E-BCS significantly improves aesthetic outcomes and QoL compared to C-O-BCS, without compromising surgical efficiency or safety for early-stage breast cancer patients, supporting its clinical adoption. Trial registration: ChiCTR2200061907. © 2026