The Evolving Landscape of Extracorporeal Photopheresis in Immunotherapy: A Comprehensive Bibliometric and Topic Modeling Analysis (1995-2024).

Abstract

Introduction: Extracorporeal photopheresis (ECP) is an established immunomodulatory therapy for graft-versus-host disease (GVHD) and cutaneous T-cell lymphoma and is increasingly investigated for immune-related adverse events (irAEs). However, its collaborative networks, thematic evolution, and translational evidence gaps remain poorly characterized.

Methods: We analyzed 1268 ECP publications from the Web of Science Core Collection (1995-2024) using bibliometric analysis and Latent Dirichlet Allocation (LDA) topic modeling. Studies published after the search cutoff were considered only for clinical context.

Results: The United States, Germany, and Italy led publication output. Mann-Kendall analysis identified a significant change point around 2015. LDA revealed six thematic domains: early research emphasized dermatologic applications and solid organ rejection, whereas recent work shifted toward acute GVHD management and immunoregulatory mechanisms. Topic 6 captured mechanistic research on apoptosis and regulatory T-cell-mediated immune tolerance. Contextual prospective evidence in GVHD and irAEs suggested corticosteroid-sparing activity and generally favorable tolerability, but was limited by small cohorts, heterogeneous schedules and endpoints, and few randomized comparisons.

Conclusion: ECP has evolved into a broader immunomodulatory platform, whereas its use for irAEs remains investigational. Future research should prioritize multicenter randomized trials, pediatric-specific protocols, predictive biomarkers, long-term tumor-control follow-up in irAEs, and health-economic evaluation.