PHOTODYNAMIC THERAPY; STATE OF THE ART AND FUTURE PERSPECTIVE

Abstract

Photodynamic therapy (PDT) is an anti-cancer treatment that consists of a photosensitizer (PS), which is followed-by laser illumination with a wavelength specific to the PS. In the early 1990s, a first generation porphyrin-based PS was approved for early gastric cancer or superficial esophageal cancer. However, its use was not widespread due to the high incidence of skin phototoxicity and long sunshade period, and the subsequent development of ESD for early gastrointestinal cancer. In the western countries, conventional PDT has been used for the eradicative treatment of Barrettʼs esophagus or palliative treatment of advanced esophageal cancer or cholangiocarcinoma. Although favorable results for these treatments have been reported, drug-free radio frequency ablation has become the mainstream for those indications. PDT using second generation PS with less phototoxicity and requiring a shorter sunshade period was introduced as a treatment for local failure after chemoradiotherapy for esophageal cancer, and was approved with excellent efficacy and safety after clinical trials in Japan in 2015. Now approved for local failure of esophageal cancer, 2nd generation PDT is gradually becoming popular in our country; however, the indicated cases are still limited for the treatment of GI cancer. In recent years, there have been several molecularly targeted or tumor-specific approaches using drug delivery systems that are supported by basic research, and photoimmunotherapy that targets EGFR is in clinical trials. Growing knowledge of PDT will encourage its clinical application in the future.