Liver cancer is a global health challenge and its incidence is growing worldwide, with more than 1 million cases per year by 2025. While hepatocellular carcinoma (HCC) is the most common form of liver cancer, hepatic metastases of colorectal carcinoma (CRC) are the natural disease evolution in almost 50% of patients with CRC. For both HCC and CRC liver metastases, surgical resection represents the only chance of longterm survival. In this context, a label-free optical diagnostic and/or surgical guidance tool would be highly suitable to reduce possible positive margin and improve the patient disease outcome. In this study, we used a custom-made autofl uorescence lifetime fiber-based imaging instrumentation1 to provide real-time discrimination of tumor from perilesional tissues in freshly excised liver samples. The proposed approach allowed discriminating tumor from perilesional tissue, reporting the fl uorescence lifetime decay of cellular metabolic markers, i.e. NADH and FAD(H). In particular, we reported about the characterization and delineation of tumor against healthy margin in different clinical cases of gastrointestinal tissues2, demonstrating the capability of our method. The approach was further validated on a larger statistic by examining around 30 surgical specimens of both HCC and CRC hepatic metastases, demonstrating that this approach is a powerful method for delineating tumor borders as well as for differentiating HCC from CRC metastases to the liver. The obtained results, together with the capability to acquire and process images in real time under bright background enables our methodology to be translated into surgical and clinical instrumentation for label-free tissue diagnostics and surgical guidance.

References
[1] J. L. Lagarto, V. Shcheslavskiy, F. S. Pavone, and R. Cicchi, “Real‐time fi ber‐based fl uorescence lifetime imaging with synchronous external illumination: A new path for clinical translation,” J. Biophotonics, vol. 13, no. 3, Mar. 2020.
[2] D. Suraci, E. Baria, L. Tirloni, J.L. Lagarto, S. Buccianti, C. Agostini, S. Pillozzi, L. Antonuzzo, A. Taddei, and R. Cicchi, “Time-resolved autofl uorescence imaging of freshly excised liver biopsies using an optical fi ber probe”, Proc. SPIE, 12846-22