Photodetection and Safety of 5-Aminolevulinic Acid-Induced Porphyrin in Patients With Cervical Intraepithelial Neoplasia

Background and Objectives 5-Aminolevulinic acid (5-ALA) is a porphyrin-based photosensitizer and has been used for photodynamic therapy of cervical intraepithelial neoplasia (CIN). In this study, photodetection and safety of 5-ALA-induced porphyrin in CIN tissues were assessed. Study Design/Materials and Methods A total of 42 patients for whom colposcopy or loop electrosurgical excision procedure (LEEP) was planned were administered 10%, 20%, or 30% 5-ALA locally on the surface of the cervix for 1.5-18 hours. At different times after application, the fluorescence intensity of 5-ALA-induced porphyrin on CIN and non-CIN lesions of the cervix was detected. Results Fluorescence intensity was correlated with drug concentration and application time. With 20% 5-ALA, the porphyrin fluorescence intensity increased over time, reaching a peak after 6 hours of application intervals in CIN. There was no significant difference in fluorescence intensity between CIN lesions and chronic cervicitis (benign tissue) or among CIN lesions of different severities. Three adverse events were considered related to the drug; however, these had no significant correlation with the drug concentration or application time. Conclusions 5-ALA at 10%-30% concentration is safe in patients with CIN. For further treatment, we recommend the application of 20% 5-ALA, 6 hours before photodynamic therapy in CIN. Clinical Trial Registration This study was registered at (registration number: CTR20130326) in accordance with the requirements of the National Medical Products Administration in China. Considering that there is no English version of the above website, we made a retrospective registration on (registration number ChiCTR1800016755) in 2018. Lasers Surg. Med. (c) 2020 Wiley Periodicals LLC