Usefulness of simultaneous type image-enhanced endoscope system in photodynamic therapy for centrally located lung cancer

Abstract

Background: Photodynamic therapy (PDT) is established as one of the standard treatment options for centrally located early lung cancer. In order to improve the effectiveness of PDT, it is very important to accurately diagnose the extent of the tumor and focus the laser irradiation accurately. With the use of the conventional video-endoscope system, which adopts the frame-sequential (RGB-based) display method, mainly used in Japan, for PDT laser irradiation, the system only recognizes the strong white light, and color information is lost. Therefore, it is difficult to irradiate the lesion while simultaneously observing the lesion. In this study, we investigated the usefulness of a new type of video-endoscope system during PDT.Methods: We used ELUXEO 7000® (FUJIFILM, Japan), which is a simultaneous-type video-endoscope system that has been in use at Nippon Medical School Hospital since October 2018. We analyzed the clinical usefulness of the ELUXEO® system for PDT as compared to other endoscope systems, such as EVIS LUCERA ELITE® (Olympus, Japan), an autofluorescence imaging (AFI) system.Results: After the administration of talaporfin sodium for PDT, the tumor lesion was not visualized in magenta color with AFI, yielding false-negative results. On the other hand, no false-negative results after the administration of talaporfin sodium were obtained with the use of ELUXEO®. Using the ELUXEO® system in the blue light imaging (BLI) mode, we were able to deliver a red laser light while observing the extent of the tumor. Missed laser exposure was avoided and the accuracy of PDT was improved with the use of this system.Conclusions: ELUXEO® is useful for accurate evaluation of the extent of centrally located lung cancer and therefore, for accurate laser irradiation of the tumor lesion.