Topical photodynamic therapy (PDT) for selected nonmelanoma skin cancer using 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) has yielded high long-term complete response rates with very good cosmesis. Pain during light activation of the photosensitizer can be a serious adverse event. A 2-step irradiance protocol has previously been shown to minimize ALA-PDT pain.
To determine the irradiance-dependent pain threshold for MAL-PDT, to adapt the 2-step protocol to a light-emitting diode (LED) light source, and assess clinical response.
In this prospective study, 25 superficial basal cell carcinoma (sBCC) received an initial irradiance by laser at 40 or 50 mW/cm2, or LED at 35 mW/cm2 followed by an irradiance at 70 mW/cm2 for a total of 75 J/cm2. Pain levels were recorded for both irradiance steps. Efficacy was assessed at 6, 12, or 24 months.
Pain was mild in the 40/70 mW/cm2 laser cohort. Three instances of irradiance-limiting pain occurred at 50/70 mW/cm2. Pain was minimal in the 35/70 mW/cm2 LED cohort. Clinical response rates were 80% in the 50/70 mW/cm2 laser cohort and 90% in the 35/70 mW/cm2 LED cohort.
Topical PDT can be effectively delivered to sBCC with minimal treatment-related pain by a 2-step irradiance protocol.
*Department of Dermatology, University of Arizona Cancer Center, Tucson, Arizona;
Departments of †Cell Stress Biology/PDT Center,
§Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, New York;
‖Department of Imaging Sciences, University of Rochester, Rochester, New York
Supported by NCI grants P01CA55791 and P30CA16056 and a grant from the Roswell Park Alliance.
The authors have indicated no significant interest with commercial supporters.