Localized gold nanoparticles-mediated photothermal therapy for head and neck cancer: in vivo proof-of-concept

Head and neck cancer (HNC) is the sixth most common cancer worldwide and remains associated with high mortality. Current therapeutic approaches are often aggressive and lead to functional impairment and disfigurement, reducing quality of life. Minimally invasive and more localized treatment strategies are needed. Gold nanoparticles (AuNPs)-mediated photothermal therapy (PTT) has emerged as a promising approach due to the high photothermal conversion efficiency of AuNPs and their ability to generate localized heat upon near-infrared (NIR) irradiation. This study evaluates the potential of AuNP-mediated PTT for HNC as a proof-of-concept. For this, the physicochemical and optical properties of the AuNPs were characterized. They demonstrated long-term stability, for up to one year, and photothermal stability, maintaining performance throughout four irradiation cycles. The efficacy of AuNPs-mediated PTT was assessed in vivo using two murine models differing in tumor location (neck or flank). Following intratumoral administration of AuNPs and repeated laser irradiation cycles, a clear photothermal effect was observed, associated with increased tumor necrosis and a trend toward reduced tumor progression. Biodistribution studies revealed an accumulation of the AuNPs at the tumor. Importantly, safety assessments showed no significant alterations, indicating the absence of systemic toxicity following treatment. Overall, the developed AuNPs demonstrated long-term physicochemical stability, robust photothermal performance, strong intratumoral accumulation and a favorable safety profile. These findings support the potential of AuNPs-mediated PTT as a localized and minimally invasive therapeutic strategy for HNC. Further studies will include the assessment of the long-term therapeutic outcomes to advance this approach towards clinical translation.