The identification of breast cancer by Near-Infrared fluorescence imaging with methylene blue.

e12591 Background: Breast cancer lacks an effective means to determine tumor boundaries. Most patients choose radical mastectomy to reduce the recurrence rate. However, with the pursuit of life quality, breast-conserving surgery is accepted by more and more patients. For breast-conserving surgery, we need an effective assessment to identify the tumor boundary, so as to detect the lesion area accurately and reduce the resection range. Methods: As a clinically approved dye, methylene blue(MB) is commonly used as a blue dye for sentinel node biopsy in breast cancer. Besides the visible characteristic, MB also has the near-infrared (NIR) fluorescence properties (excitation: 668 nm, emission: 688nm). Recently MB was confirmed to detect the breast tumors through intravenous injection with NIR fluorescence imaging. Up to now, we have enrolled 12 patients with radical mastectomy in Liaoning Cancer Hospital. 3 of them were injected with 0.5 mg / kg MB intravenously, and the remaining 9 were 1 mg / kg. The injection time was about 3 hours before surgery. Results: After the radical mastectomy, we detected the fluorescence signal in the resected specimen. The results of 3 cases with injection dose of 0.5mg/kg were failed. 7/9 cases with injection dose of 1mg/kg were able to be detected fluorescence signal in the breast tumors. The average tumor-to-background ratio (TBR) was 1.578±0.36. Conclusions: As a safe dye approved by FDA, Methylene Blue with NIR fluorescence imaging is a feasible way to detect breast tumors. It has the potential to real-time detect residual tumors and tumor boundaries for breast-conserving therapy.