Recent Advances in Photodynamic Imaging and Therapy in Hepatobiliary Malignancies: Clinical and Experimental Aspects

Abstract

The therapeutic and diagnostic modalities of light are well known, and derivative photodynamic reactions with photosensitizers (PSs), specific wavelengths of light exposure and the existence of tissue oxygen have been developed since the 20th century. Photodynamic therapy (PDT) is an effective local treatment for cancer-specific laser ablation in malignancies of some organs, including the bile duct. Although curability for extrahepatic cholangiocarcinoma is expected with surgery alone, patients with unresectable or remnant biliary cancer need other effective palliative therapies, including PDT. The effectiveness of PDT for cholangiocarcinoma has been reported experimentally or clinically, but it is not the standard option now due to problems with accompanied photosensitivity, limited access routes of irradiation, tumor hypoxia, etc. Novel derivative treatments such as photoimmunotherapy have not been applied in the field hepatobiliary system. Photodynamic diagnosis (PDD) has been more widely applied in the clinical diagnoses of liver malignancies or liver vascularization. At present, 5-aminolevulinic acid (ALA) and indocyanine green (ICG) dyes are mainly used as PSs in PDD, and ICG has been applied for detecting liver malignancies or vascularization. However, no ideal tools for combining both PDD and PDT for solid tumors, including hepatobiliary malignancies, have been clinically developed. To proceed with experimental and clinical trials, it is necessary to clarify the effective photosensitive drugs that are feasible for photochemical diagnosis and local treatment.

Indocyanine green fluorescence imaging to localize insulinoma and provide three-dimensional demarcation for laparoscopic enucleation: a retrospective single-arm cohort study

“…ICG fluorescence imaging was first utilized for surgical navigation and localization of liver tumors. Subsequently, various studies have demonstrated its utility in nonhepatic solid tumors 22 , 24 – 26 . ICG fluorescence imaging has shown advantages in identifying pulmonary nodules, gliomas, breast cancer, head and neck cancer, and peritoneal carcinomatosis from ovarian and colorectal cancer 27 – 32 .…”

Promising Highly Targeted Therapies for Cholangiocarcinoma: A Review and Future Perspectives

“…Despite ingenuity and improvements in the above-mentioned modalities, PDT monotherapy has limitations, such as incomplete tumor killing or recurrence, and has not replaced existing antitumor therapies. In the field of biliary tract cancer, PDTs mainly for ECC have been clinically performed worldwide since the 1990s (Table 2) [75][76][77]. However, since the 2000s, some RCTs and one meta-analysis have revealed that PDT could yield significantly longer survival/higher survival rates than supportive care with biliary drainage [78][79][80][81][82][83][84].…”

A highly efficient polydopamine encapsulated clinical ICG theranostic nanoplatform for enhanced photothermal therapy of cervical cancer

“…19,20 ICG has been utilized to detect liver malignancy or vascularization in clinical operation. 21 Besides, ICG is also one of the popular PTA. 22 However, the poor photothermal stability and short in vivo circulation time of ICG limited its further application in the biomedical applications.…”