For many cancer patients, the primary treatment plan is tumor resection, but in the quest of retaining as much healthy tissue as possible, it is impossible for surgeons to know whether they have removed all traces of the cancerous tissue without immediate analysis of resection borders. Therefore, extracted tissue is currently delivered to pathology to ascertain whether tumor cells are found near the resection edges, indicating incomplete tumor removal. This process is work intensive and time consuming, leading to prolonged operation time. In case of postoperative finding of positive resection margins, the patient has to return to the operating theater.
A new imaging technique may give doctors the ability to analyze the tumor right in the OR, and know immediately which tissue areas need to be removed. Multiphoton microscopy enables analysis of tissue structures down to subcellular resolution based on the morpho-chemical information retrieved from optical signals generated by endogenous tissue constituents by irradiation with short-pulsed lasers. The technique is gaining increasing attention in medicine for fast pathology without tissue preparation as well as for intravital microscopy. For instance, label-free multimodal multiphoton microscopy (thereafter indicated as LF3M) combining simultaneous acquisition of CARS, TPEF and SHG allows imaging of lipid-rich structures (e.g. lipid droplets), of collagen (e.g. in fibrotic tissue and blood vessels) and of other endogenous intra- and extra-cellular fluorophores (elastin, NAD(P)H, FAD, lipofuscin).
LF3M is still unexplored for hepatic tumors, whose treatment may gain great benefit from intraoperative precise detection of tumor boundaries. Complete resection with tumor-free resection margins is crucial for patients’ oncological outcome. This is true for primary hepatic cancers as hepatocellular carcinomas as well as secondary hepatic cancers as colorectal liver metastases. Until present, medical applications of LF3M in medicine were limited to large scanning microscopes that could only be used in research laboratories.
- develop multiphoton microscopic methods for label-free intraoperative detection of tumor borders and infiltrations by performing optical biopsies in situ, i.e., before and after tissue resection.
- definition of morpho-chemical parameters that enable to discriminate primary and metastatic cancer from normal or cirrhotic liver tissue based on LF3M images.
- development of tools for automated liver cancer recognition in those images
- assessment of a compact multiphoton microscopy device in the operating theater, for inspection of resected tissue directly during surgeries either inside or before the OR