PDT with ALA and MAL is established as a relatively effective treatment for non-melanoma skin cancer and premalignancies. PDT is often repeated, because a single treatment gives poor long term results. Preclinical studies showed that ALA-PDT applying a fractionated illumination scheme with a small first light fraction and a second larger light fraction separated by a dark interval of two hours resulted in a significant increase in efficacy. Whereas the efficacy was not enhanced by fractionating MAL-PDT, indicating that ALA-PDT mechanism is not the same as MAL-PDT mechanism. The increase in efficacy using fractionated PDT was confirmed clinically. A randomized comparative clinical study comparing fractionated ALA-PDT versus non-fractionated ALA-PDT in the treatment of superficial basal cell carcinoma showed a significant higher response rate in the lesions treated with fractionated ALA-PDT after a follow-up of one year (p<0.002, log-rank test). The five year follow-up is studied at moment. So far the complete response in the group treated with fractionated ALA-PDT seems to be only a few percentages lower compared to the one year follow-up. Besides the gain in response rate, fractionated ALA PDT is cost effective. ALA gel is less expensive than the commercially available MAL (Metvix®) and moreover fractionated ALA-PDT takes one treatment day, instead of two treatment days using the Metvix® treatment protocol (two MAL-PDT treatments separated by one week), both reducing direct and indirect costs and the burden to the patient.

5-aminolevulinic acid, ALA, fractionated illumination, MAL nonmelanoma skin cancer, methylaminolevulinic acid, PDT, Photodynamic therapy, protoporhyrin IX, superficial basal cell carcinoma
dx.doi.org/10.1117/12.828542, hdl.handle.net/1765/58420
12th World Congress of the International Photodynamic Association - Photodynamic Therapy: Back to the Future
Department of Dermatology

de Vijlder, H.C, Middelburg, T.A, de Bruijn, H.S, Robinson, D.J, Neumann, H.A.M, & de Haas, E.R.M. (2009). Fractionated PDT with 5-aminolevulinic acid: Effective, cost effective and patient friendly. Presented at the 12th World Congress of the International Photodynamic Association - Photodynamic Therapy: Back to the Future. doi:10.1117/12.828542