L-ICG as an optical agent to improve intraoperative margin detection in breast-conserving surgery: a prospective study.

Purpose: Precise tumor excision is important in breast-conserving surgery (BCS). This study explores the safety and accuracy of fluorescence image-guided BCS (FIGS) using a lidocaine mucilage-ICG compound (L-ICG).

Methods: 54 patients who underwent BCS from August 2020 to September 2023 were enrolled. L-ICG was locally injected 0.5 cm from the tumor border. FIGS was performed to guide the tumor excision. Frozen sectioning of surgical field biopsies was used to assess the intraoperative margin status. The primary outcome measures were margin width and positive margin rates. Cosmetic outcome was evaluated by the modified version of Breast-QTM Breast-Conserving Therapy Module (Postoperative) and breast cosmetic outcome assessment criteria.

Results: The median cranial, caudal, medial, and lateral margin widths were 8 mm (interquartile range [IQR], 3-14), 5.5 mm (IQR, 2-15), 6 mm (IQR, 3-15), and 8 mm (IQR, 3-15), respectively. Five out of 54 (9.3%) patients had an intraoperative positive margin. Intraoperatively extended resection was performed for four patients and mastectomy for the remaining one. This further reduced the positive margin rate to 1.9% at final histopathology. 50 patients received cosmetic outcome evaluation, 100% of them were "somewhat satisfied" or "very satisfied" with the appearance of the operated breast when clothed and 98% of them were scaled as "Good" or "Excellent" in their appearance of the operated breast. No serious adverse events were observed. With a median follow-up of 12.8 months, no events for tumor relapse were observed.

Conclusion: L-ICG-based FIGS is a promising technique to guide precise tumor excision in BCS.