Topical photodynamic therapy combined with ablative "light needles" against basal cell carcinoma

Basal cell carcinoma (BCC), a non-melanoma cancer with high morbidity in the elders, is a type of limited skin cancer with a projected appearance. Traditional treatments such as oral or injection administration are likely to result in serious side effects. Here, we developed a strategy that combined photodynamic therapy (PDT) with ablative light "needles" (carbon-dioxide laser) for the treatment of BCC, involving β-Tetra-(4-carboxyl-phenoxy)-zinc phthalocyanine (ZnPC₄) cubic phases with high drug loading, easy preparation, long local retention, good spreading ability and little toxicity. A model of nude mice with BCC was established for the study of pharmacodynamics. The light needles of low energy (53 mJ/cm²) used here could promote transdermal absorption of ZnPC₄ cubic phases while those of high energy (238 mJ/cm²) alone could completely kill tumor cells with no recurrence. However, ZnPC₄ cubic phases alone could not completely inhibit tumor growth, for it was distributed mainly at the topical administration site in the absence of any adjuvant technology. Therefore, the combination of photodynamics and light needles offered a good solution. Especially, the combined use of light needles with high energy and ZnPC₄ cubic phases can treat BCC efficiently with no recurrence. This approach is expected to be a novel and promising medication against BCC.