580 Background: Breast-conserving surgery (BCS) is the standard treatment for early-stage breast cancer and is increasingly preferred by younger patients. The key challenge in BCS is ensuring complete tumor removal while preserving healthy breast tissue. Surgical margin assessment plays a crucial role in reducing the risk of local recurrence. Traditional intraoperative frozen sections (FS) are time-consuming, limit sampling, and may cause tissue damage. This study evaluates the performance of EndoScell, a handheld fluorescence microscopy system, as a rapid and efficient alternative for intraoperative margin assessment. Methods: EndoScell provides real-time, high-resolution imaging of tissue margins during surgery. This system rapidly stains and scans tissue, allowing for micron-level visualization of cellular features. In this study, EndoScell was used to scan marked surfaces of breast tissue during surgery. The surgeon performed an initial assessment, while images/videos were recorded. Specimens were then sent for intraoperative FS analysis for comparison. If FS identified positive margins, the area was re-excised by 3–5 mm, and the process was repeated. Routine paraffin pathology served as the gold standard, with blinded side-by-side reading of ES images to evaluate consistency. Results: As of December 31, 2025, 300 patients undergoing BCS were included. EndoScell demonstrated high diagnostic accuracy with a sensitivity of 96.4%, specificity of 95.1%, and AUC of 0.953, showing strong agreement with paraffin pathology. Notably, the time required for EndoScell imaging was significantly shorter than FS, with an average of 3.14 ± 1.48 minutes compared to 37.50 ± 13.34 minutes for FS (P<0.001), leading to substantial improvements in surgical efficiency. Conclusions: This study confirms the feasibility and non-inferiority of EndoScell for intraoperative margin assessment in breast-conserving surgery. The system enables real-time decision-making, reducing secondary surgeries, improving outcomes, and enhancing surgical safety. Its significant clinical and social value supports further development and implementation. Key metrics related to diagnostic accuracy and time efficiency between EndoScell and traditional frozen section methods. Metric EndoScell (ES) Frozen Section (FS) Positive Margin 54 56 Negative Margin 246 244 Sensitivity 0.964 1.000 Specificity 0.951 1.000 AUC 0.953 (95% CI: 0.912–1.003) 1.000 Imaging Time (min) 3.14 ± 1.48 37.50 ± 13.34 p-value <0.001 N/A Cohen's d -3.64 N/A
Wáng et al. (Wed,) studied this question.