Abstract:

Background and purpose: In breast cancer surgery, margin status assessment significantly impacts patient prognosis, with positive margins indicating higher recurrence and metastasis risks. Ensuring complete tumor resection is thus critical for surgical success. Indocyanine green (ICG) has garnered attention for its potential real-time imaging of breast cancer lesions under near-infrared light. This study employed ICG for intraoperative assessment of breast cancer lesion margin status and further explored the possibility of optimizing the safe margin distance surround the lesion in normal breast tissue. Methods: Clinical data of patients admitted to the Department of Thyroid and Breast Surgery, the Fourth Affiliated Hospital of Anhui Medical University (Affiliated Chaohu Hospital), from December 2021 to September 2022 were collected. A retrospective clinical study was conducted on breast cancer patients who were randomly assigned to either the ICG group or the conventional surgery group. Two to three hours before surgery, patients in the ICG group received a peripheral intravenous injection of 0.5 mg/kg ICG. Intraoperative fluorescence imaging was performed on the specimen before and after resection, as well as on the residual cavity. Near-infrared fluorescence imaging equipment was used to quantitatively measure fluorescence intensity of resected lesions at 4 directions (12, 3, 6, and 9 o'clock) and detect fluorescence in the residual cavity after lesion removal. Specimens were promptly sent to the pathology department for pathological examination, and safety margins of normal breast tissue in the 4 directions were recorded. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was followed for this study. This study was approved by the Ethics Committee of the Fourth Affiliated Hospital of Anhui Medical University (Affiliated Chaohu Hospital) (No. KYXM-202310-46). Results: This study included 50 breast cancer patients, with 24 in the ICG group and 26 in the traditional surgery group. In the ICG group, fluorescence signals were detected at all lesion sites. Specifically, fluorescence density values at the lesion center, margin, and surrounding normal breast tissue were measured as 251.08±10.73, 208.08±19.74, and 156.76±16.47, respectively, showing a gradual decrease from center outward with statistically significant differences (P<0.05). Additionally, fluorescence ratios between the lesion center and margin, and center and surrounding normal tissue, were 1.22±0.13 and 1.62±0.19, respectively. After resection, abnormal fluorescence was observed in 2 of 24 cases in the residual cavity, with 1 case being invasive carcinoma with ductal carcinoma in situ and the other normal breast tissue. Ultimately, this study demonstrated that ICG achieved a sensitivity of 95.9% and a specificity of 97.9% in margin assessment. After specimen resection, the safety margins of normal glandular tissue surrounding the lesion were measured. The safety widths for the ICG group and the concurrent breast cancer surgery group were (8.36±6.42) mm and (15.08±4.75) mm, respectively. This difference was statistically significant (P<0.05). Conclusion: ICG is a real-time, efficient, and cost-effective tracer that can be used to determine breast cancer margins, with excellent sensitivity and specificity. For early-stage breast cancer patients who are eligible for breast-conserving surgery, this tracer helps to reduce the amount of healthy breast tissue that is removed around the lesion.

Key words: Indocyanine green, Breast cancer, Breast-conserving surgery, Surgical fluorescence imaging, Resection, Diagnosis, Safety range