Predictive Value of EGFR Expression for the Efficacy of Near-Infrared Photoimmunotherapy in Head and Neck Cancer

Near-infrared photoimmunotherapy (NIR-PIT) has emerged as a promising treatment for unresectable locally advanced or recurrent head and neck cancer. This study aimed to identify potential predictors of NIR-PIT efficacy before treatment by focusing on blood biomarkers in addition to pathological findings, including epidermal growth factor receptor (EGFR) expression in tumors.

A retrospective analysis of the medical records of 10 patients with head and neck cancer, who exhibited confirmed EGFR expression and underwent NIR-PIT treatment at Akita University Hospital from December 2021 to April 2024, was conducted (13 cycles of NIR-PIT). EGFR expression, cluster of differentiation (CD)4/CD8 ratio, regulatory T cell (Treg) frequency, serum albumin, neutrophil-to-lymphocyte ratio (NLR), and neutrophil-to-eosinophil ratio (NER) were calculated from the tumor tissue and blood collected immediately before treatment. Correlations of these factors with tumor response to NIR-PIT were determined.

The objective response rate (ORR) was 61.5% and the disease control rate (DCR) was 100%. A statistically significant association was observed between the EGFR index and tumor response. No statistically significant correlation was found between other biomarkers (CD4/CD8 ratio, Treg frequency, serum albumin, NLR, NER) and tumor response.

These findings underscore the important role of EGFR expression in predicting the efficacy of NIR-PIT in the management of head and neck cancer, and highlight the significance of incorporating EGFR assessment in patient selection and optimized treatment strategies. Further studies are needed to elucidate the role that these other potential predictors, including tumor immune response markers, play in NIR-PIT outcomes.