Vascular and tissue effects of photodynamic therapy in a murine cutaneous tumor model.

Skin cancer is the most common neoplasm worldwide and presents a significant health concern. Topical photodynamic therapy (PDT) has emerged as a therapeutic option for treating malignant and potentially precancerous skin lesions. To improve this technique and design more effective protocols, it is vital to understand the relationship between PDT damage in blood vessels and surrounding tissues. In this study, solid tumors of squamous cell carcinoma (SCC) were induced in balb/c nude mice. Damages were evaluated using histology and optical coherence tomography (OCT) images to compare PDT protocols using systemic and topical photosensitizer (PS) administration with different irradiances. The results are promising and may support the development of new and more effective PDT protocols for clinical treatment, including those that require multiple treatment sessions.