Real-World Effectiveness and Safety of Photoimmunotherapy for Head and Neck Cancer: A Multicenter Retrospective Study

Background/Objectives: Photoimmunotherapy for head and neck cancer (HN-PIT) is an emerging treatment for unresectable locally advanced or recurrent head and neck cancer; however, little real-world data (RWD) are available. The aim of this multicenter, retrospective study was to examine the effectiveness and safety of HN-PIT. Methods: Forty patients who underwent HN-PIT between from 2021 to August 2024 were included. The primary endpoint was time to treatment failure (TTF), and the secondary endpoints were the overall response rate (ORR), overall survival (OS), progression-free survival (PFS), and adverse events (AEs). Results: The median TTF was 6.0 months, and the 1-year treatment failure rate was 23.2%. The ORR was 75%, the disease control rate was 95%, the median OS was 26.9 months, and the median PFS was 6.2 months. The most common AE was pain, which occurred in 37 patients (92.5%), and grade 3 pain occurred in five patients (12.5%). Mucositis occurred in 32 patients (80.0%), grade 3 mucositis occurring in 3 patients (7.5%). Hemorrhages were observed in 31 patients (77.5%); however, no grade 3 or higher hemorrhages were observed. Sepsis was observed in two patients (5.0%; grades 4 and 5). Laryngeal edema was observed in 17 patients (42.5%), 4 with grade 4 edema (10.0%). Conclusion: Our RWD demonstrated that HN-PIT has satisfactory effectiveness and an acceptable safety profile. TTF may be useful as an endpoint reflecting the characteristics of this treatment, and this study provides important basic data for the development of future treatment strategies.