Knowledge mapping of photodynamic therapy in bladder cancer: a bibliometric analysis (2000-2025)

Bladder cancer (BC) is the sixth most common cancer in men and one of the top 10 cancers in terms of the global cancer burden. Despite the rapid development and widespread application of photodynamic therapy (PDT) in BC research, a comprehensive analysis and bibliometric evaluation of the development trends in this field have yet to be conducted. This study aims to quantify and visualize the research output, major contributors, intellectual structure, and emerging frontiers in photodynamic therapy for bladder cancer research from 2000 to 2025.

Articles on PDT in BC published from 2000 to 2025 were retrieved from the Web of Science Core Collection (WoSCC) database. A bibliometric analysis was performed using VOSviewer, CiteSpace, Python, and the R package "bibliometrix".

A total of 595 articles from 42 countries were included in the analysis, of which the majority originated from China and the United States. The number of publications related to PDT in BC continues to increase annually. The National University of Singapore, the University of Leuven, the German National Cancer Center, and the University of Coimbra in Portugal were the main research institutions with the highest publication volumes. Photodiagnosis and Photodynamic Therapy was the leading journal in this research area, while The Journal of Urology was the most frequently co-cited publication. A total of 106 authors contributed to these articles, of whom, Fernandes and Olivo contributed the highest number of publications, and Dougherty was the most commonly co-cited author. The main research topics in this field included the development and optimization of novel photosensitizers, combination therapy strategies, and the integration of photodynamic diagnosis and therapy. Further, the core keywords representing emerging research hotspots included "hypericin", "5-aminolevulinic acid", "protoporphyrin IX", "photosensitizer", "nanoparticles", and "immunotherapy".

A bibliometric analysis was conducted to examine research on PDT in BC from 2000 to 2025. The investigation identified key trends, collaborative networks, and central research themes, including the application of hypericin and the integration of immunotherapy. While China and the United States were the leading contributors in terms of publication output, international collaborative efforts remained relatively limited. The findings underscore a notable evolution in the field, characterized by a focus on photosensitizer optimization and the development of novel therapeutic strategies. Emerging research directions notably include advancements in nanotechnology, immunotherapeutic approaches, and combination treatment regimens. In summary, this analysis provides a comprehensive mapping of the current knowledge landscape, offering valuable insights to guide future research initiatives in this domain.