A photodynamic therapy combined with topical 5-aminolevulinic acid and systemic hematoporphyrin derivative is more efficient but less phototoxic for cancer.

Abstract

Although photodynamic therapy (PDT) has been shown to be effective in cancer treatment, its side effects, such as a long-lasting skin photosensitivity after the application, still cause patient's inconvenience. In this retrospective cohort study, our objective was to explore a more efficient but less phototoxic PDT for skin cancers. The PDT combined with a topical photosensitizer 5-aminolevulinic acid (ALA) and an intravenously injected light-sensitive agent hematoporphyrin derivative (HPD) was used to treat 26 patients with 41 skin cancer lesions in head and face. The findings were then compared with the results of the HPD-PDT alone and the ALA-PDT following CO2 laser ablation on 28 and 41 skin cancer patients, respectively. The complete remission rate for the combined PDT was 100 % in 2 months and 97.6 % in a 6 months to 6 years trial after the treatment compared with those of 92.9 and 95.1 % for the HPD-PDT and the ALA-PDT after a single treatment, respectively. Moreover, while the patient treated with the HPD-PDT needs to avoid strong light exposure for 4-5 weeks, the combined PDT significantly reduced the period to 10-14 days. Also, in the combined PDT, the dose of the HPD, a pro-toxic light-sensitive drug, was much lower than that in the HPD-PDT. The combined PDT not only shows high cure rate for skin cancers but also decreases the dose of the pro-toxic HPD and significantly shortens the photosensitive period, from which the patients are able to benefit.