Near-infrared photoimmunotherapy for recurrent cancer at the base of the tongue.

Near-infrared photoimmunotherapy (NIR-PIT) is a novel therapeutic approach that targets epidermal growth factor receptor (EGFR). In NIR-PIT, administration of cetuximab sarotalocan sodium is followed by laser irradiation of the affected area, which theoretically should induce tumor cell death. However, residual tumors are occasionally observed. This study investigated factors that influence the therapeutic efficacy of NIR-PIT in cases of recurrence of cancer at the base of the tongue. Six patients undergoing 11 treatment cycles were analyzed, focusing on the puncture interval of cylindrical diffusers and the expression of EGFR in tumors. The results demonstrated that a puncture interval of ≤12 mm significantly enhanced therapeutic efficacy, with one case achieving complete response. EGFR expression was positive in all cases and expression score showed no significant change between before and after treatment. These findings suggest that puncture interval plays a critical role in therapeutic outcomes, whereas EGFR expression may not directly influence treatment efficacy.