Needle-free injection of 5-aminolevulinic acid in photodynamic therapy for the treatment of non-melanoma skin cancer

Background. Photodynamic therapy (PDT) has been widely used in treatment for skin cancer. However, topical 5-aminolevulinic acid (ALA) in PDT demonstrates poor therapeutic effect due to its shallow penetration. And intralesional ALA-PDT can bring great pain. The purpose of this study was to evaluate the efficacy of PDT with needle-free injection of ALA in the treatment of nonmalignant skin tumors. Methods. 54 non-melanocytic malignant lesions of 54 subjects were treated with needle-free injection of 20% 5-ALA under occlusion for 1.5 hours, and irradiated with light dose of 100 J/cm(2) at 100 mW for 20 minutes. Evaluation of treatment efficacy was conducted at 2 week after treatment. Results. 44 cases showed complete response with six cycles of PDT, three cases with seven cycles, and three cases with nine cycles. The remaining four cases failed to show complete response even with nine cycle of PDT. No case was reported to have recurrence in 6 months posttreatment. Only four cases experienced disease recurrence in 1 year posttreatment. Conclusions. The treatment with PDT using needle-free injection of 5-ALA appears to be effective and well tolerated with milder therapeutic pain and low recurrence rate. It can be proposed as an effective treatment alternative for non-melanoma skin cancer.