Photodynamic therapy using topically applied 5-aminolevulinic acid for treatment of cervical cancer

Abstract

Objective: The purpose of this study was to investigate the treatment effects of a topical application of 5-aminolevulinic acid (5-ALA) for photodynamic therapy (PDT) to treat cervical cancer. Methods: We first investigated the effects of 5-ALA cream according to application time. And to find the effective 5-ALA concentration and the distribution times in vivo, 20% 5-ALA cream was topically applied to the tumor of the nude mouse. We then observed the distribution of 5-ALA via fluorescence measurement with using a 532 nm diode laser. 25 nude mice were divided into Control, ALA, Laser, and PDT group. To evaluate the PDT effect at cancer lesion, we applied 20% 5-ALA cream to the tumor by the same method, and the PDT was done by using a 632 nm diode laser at the time of the peak level of fluorescence. We checked the changes of the volume of cancer for 30 days, and then biopsy was done. Results: The effective post-irradiation time after topical ALA application was 9 hours. In the PDT group, 40% (4/10) of the mice showed decreased tumor size. Conclusion: The maximum PpIX fluorescence at 9 hours after local applicationof 5-ALA cream was checked. And PDT group did not show any statistical difference than control group in the growth of tumor size than control group. However responding cases (4/10) of PDT group showed the meaningful decrease of tumor size than control group (P