Real-world outcomes of photoimmunotherapy for oral sites in head and neck cancer: A multicentre subgroup analysis

OBJECTIVE: To evaluate clinical outcomes and supportive-care needs in photoimmunotherapy (PIT) restricted to oral sites in a multicentre real-world cohort. METHODS: We retrospectively analysed 40 consecutive patients with unresectable, locally recurrent head and neck cancer undergoing PIT between 1 January 2021 and 31 August 2024. The oral-site subgroup comprised 12 patients receiving ≥1 illumination to the oral cavity (tongue, gingiva, buccal mucosa, floor of mouth, hard palate, or flap). The primary endpoint was objective response rate (ORR). Secondary endpoints included time-to-treatment failure (TTF), overall survival (OS), progression-free survival (PFS), and adverse events (AEs). Kaplan-Meier analyses assessed time-to-event outcomes. RESULTS: Best overall responses comprised complete response, partial response, stable disease, and progressive disease in six, four, one, and one patients, respectively, yielding an ORR of 83.3 % (95 % confidence interval [CI], 51.6-97.9) and a disease control rate of 91.7 % (95 % CI, 61.5-99.8). The median TTF, OS, and PFS were 6.0 months (95 % CI, 1.4-18.3), 22.0 months (95 % CI, 6.0-unreached), and 6.0 months (95 % CI, 1.4-10.4), respectively. AEs included pain (100 %; grade≥3, 25 %), mucositis (92 %; grade≥3, 17 %), facial oedema (75 %), laryngeal oedema (67 %; grade≥3, 8 %), dysphagia (50 %), bleeding (50 %), and fistula (33 %). Commonly required supportive interventions included anticipatory analgesia, airway protection (e.g., preventive tracheostomy), and temporary enteral nutrition. CONCLUSIONS: Oral-site PIT demonstrated high antitumour activity with frequent but manageable local toxicities, necessitating proactive, multidisciplinary supportive care. This first dedicated multicentre analysis focused on oral illumination corroborates site-specific PIT evaluation and its integration within multimodal treatment strategies.