Investigation of photothermal treatment with 532 nm laser light on laryngeal cancer in an in vivo tumor model.

Laryngeal cancer is the second most common cancer in the upper aerodigestive tract, with its incidence increasing across all ages. The conventional treatments for laryngeal cancer include surgical procedure, radiation, and chemotherapy; however, these treatments can lead to various complications. Photothermal therapy (PTT) using laser light has been employed form cancer effective treatment because of its minimal invasion and short operation time. The current study aims to investigate the feasibility of 532 nm PTT on laryngeal cancer in an invivo tumor model. Ex vivo dosimetry evaluation was conducted to determine the laser irradiation conditions, and HEP-2 tumor bearing mice were used to demonstrate in vivo photothermal effects. In addition, histology and western blot analysis were conducted to verify tumor necrosis and any changes in cancer-associated factors in the tumor tissues. The current in vivo results showed that PTT at 5 W for 40 s and 20 W for 10 s had comparable effects in terms of temperature increase and tumor removal. The 532 nm PTT significantly decreased the remaining tumor and downregulated the expression levels of MMP- 9 and ERK. The current study demonstrated that the 532 nm PTT could be a feasible option for treatment of laryngeal tumor with high power delivery for a short exposure time. Further investigations will confirm the endoscopic application of the 532 nm PTT for the treatment of intralaryngeal tissue prior to clinical translation.