The Effectiveness and Safety of X-PDT for Cutaneous Squamous Cell Carcinoma and Melanoma

<b>Aim:</b> To clarify the effectiveness and safety of x-ray-activated photodynamic therapy (X-PDT) for cutaneous squamous cell carcinoma (SCC) and melanoma. <b>Materials & methods:</b> Copper-cysteamine nanoparticles were used as a photosensitizer of X-PDT. The dark toxicity and cytotoxicity were studied <i>in vitro.</i> Tumor volume, microvessel density and acute toxicity of mice were evaluated <i>in vivo</i>. <b>Results:</b> Without x-ray irradiation, copper-cysteamine nanoparticles were nontoxic for keratinocyte cells. XL50 cells (SCC) were more sensitive to X-PDT than B16F10 cells (melanoma). X-PDT successfully inhibited the growth of SCC <i>in vivo</i> (p < 0.05), while the B16F10 melanoma was resistant. Microvessel density in SCC tissue was remarkably reduced (p < 0.05). No obvious acute toxicity reaction was observed. <b>Conclusion:</b> X-PDT is a safe and effective treatment for SCC.