Photodynamic Therapy for the Treatment and Diagnosis of Cancer–A Review of the Current Clinical Status

Abstract

Photodynamic therapy (PDT) has been used as an anti-tumor treatment method for a long time and photosensitizers (PS) can be used in various types of tumors. Originally, light is an effective tool that has been used in the treatment of diseases for ages. The effects of combination of specific dyes with light illumination was demonstrated at the beginning of 20th century and novel PDT approaches have been developed ever since. Main strategies of current studies are to reduce off-target effects and improve pharmacokinetic properties. Given the high interest and vast literature about the topic, approval of PDT as the first drug/device combination by the FDA should come as no surprise. PDT consists of two stages of treatment, combining light energy with a PS in order to destruct tumor cells after activation by light. In general, PDT has fewer side effects and toxicity than chemotherapy and/or radiotherapy. In addition to the purpose of treatment, several types of PSs can be used for diagnostic purposes for tumors. Such approaches are called photodynamic diagnosis (PDD). In this Review, we provide a general overview of the clinical applications of PDT in cancer, including the diagnostic and therapeutic approaches. Assessment of PDT therapeutic efficacy in the clinic will be discussed, since identifying predictors to determine the response to treatment is crucial. In addition, examples of PDT in various types of tumors will be discussed. Furthermore, combination of PDT with other therapy modalities such as chemotherapy, radiotherapy, surgery and immunotherapy will be emphasized, since such approaches seem to be promising in terms of enhancing effectiveness against tumor. The combination of PDT with other treatments may yield better results than by single treatments. Moreover, the utilization of lower doses in a combination therapy setting may cause less side effects and better results than single therapy. A better understanding of the effectiveness of PDT in a combination setting in the clinic as well as the optimization of such complex multimodal treatments may expand the clinical applications of PDT.

Targeted Nanoparticle Photodynamic Diagnosis and Therapy of Colorectal Cancer

“…The reasoning for this is that PDD and PDT modalities were shown to possess clear advantages over classical modalities, such as minimal invasiveness, high selectivity towards cancerous tissue, and fewer side effects after treatment [44]. According to a recent review performed by Kawczyk-Krupka et al (2020) and Gunaydin et al (2021), clinical trials in relation to the utilization of PDT and PDD for diagnosis and the treatment of throat and neck cancers, as well as selected forms of liver, pancreatic, breast, and prostate cancer, were promising [45,46]. However, in terms of successful PDD and PDT combinative clinical trials, with reference to CRC, there have currently been none reported to date [45,47].…”

Targeted Photodynamic Diagnosis and Therapy for Esophageal Cancer: Potential Role of Functionalized Nanomedicine

“…Conventional therapy in combination with PDT offers a promising approach to improving the effectiveness of cancer treatment. The unique features of PDT, such as fewer side effects and extensive induction of anti-tumor immune responses, makes it favorable with other treatment approaches like surgery, radiotherapy or chemotherapy [59,60]. Surgery in combination with PDT has been well studied.…”

Autophagy and Apoptosis Induced in U87 MG Glioblastoma Cells by Hypericin-Mediated Photodynamic Therapy Can Be Photobiomodulated with 808 nm Light

“…Photodynamic therapy (PDT) is a modern trend of adjuvant therapy in which a photosensitive molecule—a photosensitizer (PS), light at an appropriate wavelength absorbed by the PS, and oxygen are involved in the photoreactions that lead to photodestruction of the tumor [ 4 ]. In recent years, PDT has been used clinically to cure lung, head and neck, brain, prostate, colon, pancreatic, cervical, breast, and skin cancers [ 5 ]. The penetration depth of light is a major obstacle in PDT [ 6 , 7 ].…”